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Materials
Number of Followers: 4  Open Access journalISSN (Print) 1996-1944 Published by MDPI  [258 journals]
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- Materials, Vol. 17, Pages 4168: Kinetics and Mechanism of SiO2 Extraction
from Acid-Leached Coal Gangue Residue by Alkaline Hydrothermal Treatment
Authors: Deshun Kong, Yuan Gao, Shuojiang Song, Rongli Jiang
First page: 4168
Abstract: Acid-leached gangue residue is produced after the gangue extraction of metal ions; the main component is silicon, which can be used to extract silica. To ascertain the kinetics and mechanism of silica extraction from acid-leached coal gangue residue, this study explored the effects of the NaOH concentration, solid-to-liquid ratio, reaction temperature, and reaction time on the extraction process. The optimized conditions, determined through this investigation, involved a NaOH concentration of 4 mol/L, a reaction time of 4 h, a solid-to-liquid ratio of 1:4, and a reaction temperature of 180 °C, yielding a SiO2 extraction ratio of 90.16%. Additionally, the leaching kinetics of silica in a NaOH solution were examined using three kinetic equations from the “unreacted shrinking core model”. The results revealed that the control type of the leaching process was the “mixing control”, and the apparent activation energy was determined to be 52.36 kJ/mol.
Citation: Materials
PubDate: 2024-08-23
DOI: 10.3390/ma17174168
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4169: Adsorption Technology for PFAS Removal in
Water: Comparison between Novel Carbonaceous Materials
Authors: Marco Petrangeli Papini, Marta Senofonte, Riccardo Antonino Cuzzola, Rania Remmani, Ida Pettiti, Carmela Riccardi, Giulia Simonetti
First page: 4169
Abstract: PFASs are a variety of ecologically persistent compounds of anthropogenic origin loosely included in many industrial products. In these, the carbon chain can be fully (perfluoroalkyl substances) or partially (polyfluoroalkyl substances) fluorinated. Their ubiquitous presence in many environmental compartments over the years and their long-lasting nature have given rise to concerns about the possible adverse effects of PFASs on ecosystems and human health. Among a number of remediation technologies, adsorption has been demonstrated to be a manageable and cost-effective method for the removal of PFASs in aqueous media. This study tested two novel and eco-friendly adsorbents (pinewood and date seeds biochar) on six different PFASs (PFOS, GenX, PFHxA, PFOA, PFDA, and PFTeDA). Batch sorption tests (24 h) were carried out to evaluate the removal efficiency of each PFAS substance in relation to the two biochars. All samples of liquid phase were analyzed by a developed and then a well-established method: (i) pre-treatment (centrifugation and filtration) and (ii) determination by high-performance liquid chromatography coupled with mass spectrometry (HPLC-MS/MS). The results evidenced a comparable adsorption capacity in both materials but greater in the long-chain PFASs. Such findings may lead to a promising path towards the use of waste-origin materials in the PFAS remediation field.
Citation: Materials
PubDate: 2024-08-23
DOI: 10.3390/ma17174169
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4170: A Review on Concrete Superplasticizers and
Their Potential Applications for Enhancing the Performance of Thermally
Activated Recycled Cement
Authors: Rong Huang, Lei Xu, Zihang Xu, Qihang Zhang, Junjie Wang
First page: 4170
Abstract: With the rapid development of the construction industry worldwide, a large amount of waste concrete is generated each year, which has caused serious environmental problems. As a green and sustainable building material, thermally activated recycled cement (RC) has received widespread attention. However, the unique properties of RC, such as the high water demand and short setting time, necessitate the use of specialized superplasticizers that are different from those used in ordinary Portland cement. As an important component for the application of RC, superplasticizer has an important impact on the performance modification of RC. This article summarizes the recent research progress of potential superplasticizers for RC, with a view to providing a reference for the research and application of superplasticizers for RC. Based on the differences between ordinary Portland cement and RC, the paper discusses potential superplasticizers that may be suitable for RC, and points out that future development of potential modified superplasticizers can include altering the molecular structure to improve adsorption onto the surfaces of RC or to enhance the durability of concrete with RC.
Citation: Materials
PubDate: 2024-08-23
DOI: 10.3390/ma17174170
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4171: Towards Sustainable Orthodontics:
Environmental Implications and Strategies for Clear Aligner Therapy
Authors: Monica Macrì, Vincenzo D’Albis, Raffaele Marciani, Matteo Nardella, Felice Festa
First page: 4171
Abstract: The increasing concern over environmental sustainability has prompted various industries to reassess their practices and explore greener alternatives. Dentistry, as a significant contributor to waste generation, is actively seeking methods to minimize its environmental footprint. This paper examines the environmental implications of clear aligner therapy (CAT) in orthodontics and explores strategies to prioritize sustainability in aligner manufacturing and usage. CAT has gained popularity as a viable alternative to traditional fixed appliances due to advancements in biomaterials and computer-aided design (CAD) and manufacturing (CAM) technologies. The global market for clear aligners is expanding rapidly, with significant growth projected in the coming years. To address these challenges, this paper proposes adopting the principles of reduce, reuse, recycle, and rethink (4Rs) in orthodontic practices. Strategies such as minimizing resource consumption, incorporating recycled materials, and promoting proper aligner disposal and recycling can significantly reduce environmental harm. This paper explores emerging technologies and materials to mitigate the environmental impacts of CAT. Additionally, initiatives promoting aligner recycling and repurposing offer promising avenues for reducing plastic waste and fostering a circular economy. In conclusion, while CAT offers numerous benefits in orthodontic treatment, its environmental impact cannot be overlooked. By implementing sustainable practices and embracing innovative solutions, the orthodontic community can contribute to a more environmentally conscious future while continuing to provide quality care to patients.
Citation: Materials
PubDate: 2024-08-23
DOI: 10.3390/ma17174171
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4172: Antimony(V) Adsorption and Partitioning by
Humic Acid-Modified Ferrihydrite: Insights into Environmental Remediation
and Transformation Processes
Authors: Wei Ding, Shenxu Bao, Yimin Zhang, Bo Chen, Zhanhao Wang
First page: 4172
Abstract: Antimony (Sb) migration in soil and water systems is predominantly governed by its adsorption onto ferrihydrite (FH), a process strongly influenced by natural organic matter. This study investigates the adsorption behavior, stability, and mechanism of FH and FH–humic acid (FH-HA) complexes on Sb(V), along with the fate of adsorbed Sb(V) during FH aging. Batch adsorption experiments reveal that initial pH and concentration significantly influence Sb(V) sorption. Lower pH levels decrease adsorption, while higher concentrations enhance it. Sb(V) adsorption increases with prolonged contact time, with FH exhibiting a higher adsorption capacity than FH-HA complexes. Incorporating HA onto FH surfaces reduces reactive adsorption sites, decreasing Sb(V) adsorption. Adsorbed FH-HA complexes exhibit a higher specific surface area than co-precipitated FH-HA, demonstrating stronger Sb(V) adsorption capacity under various conditions. X-ray photoelectron spectroscopy (XPS) confirms that Sb(V) adsorption primarily occurs through ligand exchange, forming Fe-O-Sb complexes. HA inhibits the migration of Sb(V), thereby enhancing its retention within the FH and FH-HA complexes. During FH transformation, a portion of Sb(V) may replace Fe(III) within converted iron minerals. However, the combination of relatively high adsorption capacity and significantly lower desorption rates makes adsorbed FH-HA complexes promising candidates for sustained Sb adsorption over extended periods. These findings enhance our understanding of Sb(V) behavior and offer insights for effective remediation strategies in complex environmental systems.
Citation: Materials
PubDate: 2024-08-23
DOI: 10.3390/ma17174172
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4173: Influence of Noble Metals on Morphology
and Topology of Structural Elements in Magnesium Alloy
Authors: Viktor L. Greshta, Vadim A. Shalomeev, Oleksandr S. Lukianenko, Rafał Bogucki, Kinga Korniejenko, Serhii S. Tabunshchyk
First page: 4173
Abstract: The main motivation for this study was to improve implant materials. The influence of silver and gold on the structure and mechanical properties of Mg–Nd–Zr alloy was studied. In the work, quantitative and qualitative evaluation of the structural components of magnesium alloy with noble metal additives was performed. The research methods used were investigation of the mechanical properties and observation of micro– and macrostructures. The results showed that modification of magnesium alloy with Ag and Au contributes to the formation of spherical intermetallics of smaller size groups, which become additional centers of crystallization and grind the cast structure. The best composition from additional alloying with silver and gold was determined. Their positive effect on the strength and ductility properties of the metal was established. Preclinical and clinical testing was performed and the prospects for noble metal modification of bioabsorbable magnesium alloy for implant production usage were shown.
Citation: Materials
PubDate: 2024-08-23
DOI: 10.3390/ma17174173
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4174: A Comprehensive Review on Finite Element
Analysis of Laser Shock Peening
Authors: Mayur B. Wakchaure, Manoranjan Misra, Pradeep L. Menezes
First page: 4174
Abstract: Laser shock peening (LSP) is a formidable cold working surface treatment that provides high-energy precision to enhance the mechanical properties of materials. This paper delves into the intricacies of the LSP process, offering insights into its methodology and the simulation thereof through the finite element method. This review critically examines various points, such as laser energy, overlapping of shots, effect of LSP on residual stress, effect of LSP on grain refinement, and algorithms for simulation extrapolated from finite element analyses conducted by researchers, shedding light on the nuanced considerations integral to this technique. As the significance of LSP continues to grow, the collective findings underscore its potential as a transformative technology for fortifying materials against mechanical stress and improving their overall performance and longevity. The discourse encapsulates the evolving landscape of the LSP, emphasizing the pivotal role played by finite element analysis in advancing our understanding and application of this innovative surface treatment.
Citation: Materials
PubDate: 2024-08-23
DOI: 10.3390/ma17174174
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4175: The Effect of Long-Term Aging on the
Microstructure and Properties of a Novel Nickel-Based Powder Superalloy
FGH4113A
Authors: Jiangying Xiong, Chao Yin, Chong Wang, Ganjiang Feng, Jianzheng Guo
First page: 4175
Abstract: This study investigates the microstructural evolution and its effect on the fatigue performance of a novel nickel-based powder superalloy FGH4113A (WZ-A3) after long-term aging at 760 °C and 815 °C. The results show that long-term aging both at 760 °C and 815 °C has no significant effect on the grain size and morphology of the alloy. After aging at 760 °C for up to 2020 h, the size of the γ′ phase remains unchanged, and its morphology transitions from nearly square to nearly spherical. During long-term aging at 815 °C for 440 h, γ′ phase coarsening and spheroidizing occur simultaneously. With prolonged aging time, the size and spheroidization degree of the γ′ phase further increase. During long-term aging up to 440 h at 760 °C, the dispersed granular MC and M6C carbides dissolve and re-precipitate. By 2020 h of aging, flocculent carbides precipitate and non-continuous M6C and M23C6 accumulate at grain boundaries. After long-term aging at 815 °C for 440 h, flocculent carbides begin to precipitate within the grains. By 2020 h of aging, a large amount of flocculent carbides precipitate with significant coarsening and enrichment of the grain boundary carbides. Due to the insignificant coarsening of the γ′ phase as well as the enrichment and precipitation of the grain boundary carbides, the fatigue performance of the alloy decreases slightly after long-term aging.
Citation: Materials
PubDate: 2024-08-23
DOI: 10.3390/ma17174175
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4176: Materials Properties Prediction (MAPP):
Empowering the Prediction of Material Properties Solely Based on Chemical
Formulas
Authors: Si-Da Xue, Qi-Jun Hong
First page: 4176
Abstract: Predicting material properties has always been a challenging task in materials science. With the emergence of machine learning methodologies, new avenues have opened up. In this study, we build upon our recently developed graph neural network (GNN) approach to construct models that predict four distinct material properties. Our graph model represents materials as element graphs, with chemical formulas serving as the only input. This approach ensures permutation invariance, offering a robust solution to prior limitations. By employing bootstrap methods to train this individual GNN, we further enhance the reliability and accuracy of our predictions. With multi-task learning, we harness the power of extensive datasets to boost the performance of smaller ones. We introduce the inaugural version of the Materials Properties Prediction (MAPP) framework, empowering the prediction of material properties solely based on chemical formulas.
Citation: Materials
PubDate: 2024-08-23
DOI: 10.3390/ma17174176
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4177: Characterization and Modeling of
Out-of-Plane Behavior of Fiber-Based Materials: Numerical Illustration of
Wrinkle in Deep Drawing
Authors: Cedric W. Sanjon, Yuchen Leng, Yi Yan, Peter Groche, Marek Hauptmann, Nicole Ludat, Jens-Peter Majschak
First page: 4177
Abstract: The characterization and modeling of the out-of-plane behavior of fiber-based materials is essential for understanding their mechanical properties and improving their performance in various applications, especially in the forming process. Despite this, research on paper and paperboard has mainly focused on its in-plane behavior rather than its out-of-plane behavior. However, for accurate material characterization and modeling, it is critical to consider the out-of-plane behavior. In particular, delamination occurs during forming processes such as creasing, folding, and deep drawing. In this study, three material models for paperboard are presented: a single all-material continuum model and two composite models using different cohesion methods. The two composite models decouple in-plane and out-of-plane behavior and consist of continuum models describing the behavior of individual layers and cohesive interface models connecting the layers. Material characterization experiments are performed to derive the model parameters and verify the models. The models are validated using three-point bending and bulge tests and show good agreement. A case study is also conducted on the application of the three models in the simulation of a deep drawing process with respect to wrinkle formation. By comparing the simulation results of wrinkle formation in the deep drawing process, the composite models, especially the cohesive interface composite model, show greater accuracy in replicating the experimental results, indicating that a single continuum model can also be used to represent wrinkles.
Citation: Materials
PubDate: 2024-08-23
DOI: 10.3390/ma17174177
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4178: Evaluating Optical Properties of
Mixed-Phase 2D MoSe2/Poly(vinyl alcohol) Nanocomposite Film
Authors: Suman Chhetri, Anh Tuan Nguyen, Nicolas Gaillard, Woochul Lee
First page: 4178
Abstract: Highly solar light-absorbing poly(vinyl alcohol) (PVA) nanocomposite films have garnered wide attention in fields such as flexible optoelectronics, solar energy harvesting, and photothermal therapy. However, fabricating PVA nanocomposite films with a broad spectrum of solar absorption using cost-effective and non-toxic nanofillers remains challenging. Herein, nanocomposite films of PVA incorporating various concentrations of mixed-phase 2D MoSe2 nanosheets (i.e., a combination of the 2H and 1T phase) were prepared using a solution casting technique. Scanning electron microscopy (SEM) shows homogenous dispersion of MoSe2 nanosheets in the PVA matrix even at higher concentrations, while atomic force microscopy (AFM) reveals increasing surface roughness with increasing MoSe2 content, reaching a plateau after 20 wt%. With the increase in the concentration of MoSe2, the nanocomposite films exhibit interesting light absorption characteristics reaching their highest absorption (average 94.9%) at 40 wt% MoSe2. The incorporated mixed-phase MoSe2 nanosheets induce a significant change in the energy levels of the PVA matrix, which is reflected in the reduced optical band gap energy (2.63 eV) at 40 wt% MoSe2 against pure PVA (5.28 eV). The excellent light absorption of PVA nanocomposite films across the entire range from 250 nm to 2500 nm is attributed to the thin 2D structure of MoSe2 and the presence of its mixed phase.
Citation: Materials
PubDate: 2024-08-23
DOI: 10.3390/ma17174178
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4179: Discharge Properties and Electrochemical
Behaviors of Mg-Zn-xSr Magnesium Anodes for Mg–Air Batteries
Authors: Hongxuan Liu, Tingan Zhang, Jingzhong Xu
First page: 4179
Abstract: In this work, the electrochemical and discharge properties of Mg-Zn-xSr (x = 0, 0.2, 0.5, 1, 2, and 4 wt.%) alloys used as anodes for Mg–air batteries were systematically studied via microstructure characterization, electrochemical techniques, and Mg–air battery test methods. The addition of Sr refines the grain size, changes the composition and morphology of the passivation film and discharge products, and enhances the electrochemical properties of the alloy. Excessive Sr addition breaks the grain boundaries and precipitates a large number of Sr-rich phases, resulting in microgalvanic corrosion and the ‘chunk effect’. The anode efficiency of Mg-Zn-1Sr is the highest at a current density of 10 mA cm−2, reaching 61.86%, and the energy density is 2019 mW h g−1. Therefore, Sr is a microalloying element that can optimize the electrochemical performance of Mg–air battery alloy anodes.
Citation: Materials
PubDate: 2024-08-23
DOI: 10.3390/ma17174179
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4180: Ultrasonic Cavitation Erosion Behavior of
GX40CrNiSi25-20 Cast Stainless Steel through Yb-YAG Surface Remelting
Authors: Daniela Cosma, Ion Mitelea, Ilare Bordeașu, Ion Dragoș Uțu, Corneliu Marius Crăciunescu
First page: 4180
Abstract: Laser beam remelting is a relatively simple and highly effective technique for the physical modification of surfaces to improve resistance to cavitation erosion. In this study, we investigated the effect of laser remelting on the surface of cast stainless steel with 0.40% C, 25% Cr, 20% Ni, and 1.5% Si on cavitation erosion behavior in tap water. The investigation was conducted using a piezoceramic crystal vibrator apparatus. Base laser beam parameters were carefully selected to result in a defect-free surface (no porosity, material burn, cracks) with hardness capable of generating better resistance to cavitation erosion. The experimental results were compared with those of the reference material. Surface morphology and microstructure evolution after cavitation tests were analyzed using an optical metallographic microscope (OM), scanning electron microscope (SEM), and hardness tests to explore the mechanism of improving surface degradation resistance. The conducted research demonstrated that surfaces modified by laser remelting exhibit a 4.8–5.1 times greater increase in cavitation erosion resistance due to the homogenization of chemical composition and refinement of the microstructure, while maintaining the properties of the base material.
Citation: Materials
PubDate: 2024-08-23
DOI: 10.3390/ma17174180
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4181: Fabrication of Helical Carbon Fiber
Skeleton Using Arc Glow Discharge Method
Authors: Xiye Chen, Haiyong Chen, Yongjun Bao, Yuhan Meng, Zhigang Jiang
First page: 4181
Abstract: An arc glow discharge device was used to prepare a helical carbon fiber skeleton with helical carbon fibers hooked to each other by spraying a hydrogen and ethanol mixture onto the iron wire substrate through the discharge area, using anhydrous ethanol as the carbon source. The samples were characterized by SEM, EDS, Raman and XPS. A growth mechanism of helical carbon fiber driven by C sp3 was proposed. The various growth modes of carbon fiber during the formation of carbon fiber skeleton were investigated. A ring appearance that indicated a change in the direction of carbon fiber growth was observed. And double helical carbon fiber was constructed from single helical carbon fiber in two ways. Super-large carbon fiber with a diameter of about 13 μm was observed, and it was speculated that this super-large carbon fiber is the backbone of the carbon fiber skeleton. The mechanical properties of the carbon fiber skeleton are isotropic.
Citation: Materials
PubDate: 2024-08-23
DOI: 10.3390/ma17174181
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4182: Structure and Corrosion Behavior of
Multiphase Intermetallic ZrCu-Based Alloys
Authors: Rafał Babilas, Katarzyna Młynarek-Żak, Aneta Kania, Akash A. Deshmukh, Tymon Warski, Łukasz Hawełek
First page: 4182
Abstract: Zirconium-based alloys are highly regarded by the research community for their exceptional corrosion resistance, thermal stability, and mechanical properties. In our work, we investigated two newly developed alloys, Zr42.42Cu41.18Al9.35Ag7.05 and Zr46.81Cu35.44Al10.09Ag7.66, in the form of ingots and ribbons. In the course of our investigation, we conducted a comprehensive structural and thermal analysis. In addition, an examination of the corrosion activity encompassing electrochemical studies and an analysis of the corrosion mechanisms was carried out. To further evaluate the performance of the materials, tests of their mechanical properties were performed, including microhardness and resistance to abrasive wear. Structural analysis showed that both alloys studied had a multiphase, crystalline structure with intermetallic phases. The samples in the form of ribbons showed improved corrosion resistance compared to that of the ingots. The ingot containing a higher content of copper Zr42.42Cu41.18Al9.35Ag7.05 was characterized by better corrosion resistance, while showing lower average hardness and a higher degree of abrasive wear based on SEM observations after pin-on-disc tests.
Citation: Materials
PubDate: 2024-08-23
DOI: 10.3390/ma17174182
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4183: Effect of Industrial Byproduct Gypsum on
the Mechanical Properties and Stabilization of Hazardous Elements of
Cementitious Materials: A Review
Authors: Pengfei Wu, Xinyue Liu, Xiaoming Liu, Zengqi Zhang, Chao Wei
First page: 4183
Abstract: Industrial byproduct gypsum (BPG) is a secondary product that is mainly composed of calcium sulfate discharged during industrial production. BPG primarily consists of desulfurized gypsum, phosphogypsum, and titanium gypsum, which account for 88% of the total BPG in China. The large-scale utilization of these three types of solid waste is crucial for the safe disposal of BPG. BPG contains various impurities and harmful elements, limiting its applications. The continuous accumulation of BPG poses a serious threat to the safety of the environment. Based on a literature review (2021–2023), it was found that 52% of BPG is used in the preparation of cementitious materials, and the addition of BPG results in an average improvement of 7–30% in the mechanical properties of cementitious materials. Moreover, BPG has a positive impact on the immobilization of hazardous elements in raw materials. Therefore, the utilization of BPG in cementitious materials is beneficial for its large-scale disposal. This study primarily reviews the effects and mechanisms of BPG on the mechanical properties of cementitious materials and the solidification of hazardous elements. Most importantly, the review reveals that BPG positively influences the hydration activity of silica–alumina-based solid waste (such as steel slag and blast furnace slag) and alkaline solid waste (such as carbide slag and red mud). This improves the proportion of solid waste in cement and reduces production costs and carbon emissions. Finally, this article summarizes and proposes the application of BPG in cementitious materials. The application of BPG + silica–alumina solid waste + alkaline solid-waste-based cementitious materials is expected to realize a new type of green ecological chain for the joint utilization of multiple industrial solid wastes and to promote the low-carbon sustainable development of industrial clusters.
Citation: Materials
PubDate: 2024-08-23
DOI: 10.3390/ma17174183
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4184: Modulating Electrical Properties of
Ti64/B4C Composite Materials via Laser Direct Manufacturing with Varying
B4C Contents
Authors: Wenshu Zhang, Hui Chang, Ning Dang, Lian Zhou
First page: 4184
Abstract: The modulation of electrical properties in composite materials is critical for applications requiring tailored electrical functionality, such as electromagnetic shielding and absorption. This study focuses on Ti64/B4C composites, a material combination promising enhanced electromagnetic properties. Laser direct manufacturing (LDM) was utilized to fabricate coaxial samples of Ti64 blended with TiB and TiC in various mass ratios, with sample thicknesses ranging from 0.5 mm to 3.5 mm. The electrical characterization involved assessing the dielectric and magnetic permeability, as well as impedance and reflectance, across a frequency spectrum of 2 to 18 GHz. The result reveals that TiC, when incorporated into Ti64, exhibits strong dielectric polarization and achieves a reflectivity as low as −40 dB between 7 and 14 GHz. Conversely, TiB demonstrates effective electromagnetic absorption, with reflectivity values below −10 dB in the frequency band of 8.5 to 11.5 GHz. The study also notes that a lower B4C content enhances electronic polarization and increases the dielectric coefficient, while higher contents favor ionic polarization. This shift can lead to a timing mismatch in the establishment of electron and ion polarization, resulting in a decreased dielectric coefficient. In addition, adjusting the B4C content in Ti64/B4C composites effectively modulates their electrical properties, suggesting a strategic approach to designing materials for specific electromagnetic functions.
Citation: Materials
PubDate: 2024-08-23
DOI: 10.3390/ma17174184
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4185: Application of Numerical Modeling and
Finite Element Analysis in Fused Filament Fabrication: A Review
Authors: Behseresht, Park, Love, Valdez Pastrana
First page: 4185
Abstract: Additive manufacturing (AM) is not necessarily a new process but an advanced method for manufacturing complex three-dimensional (3D) parts. Among the several advantages of AM are the affordable cost, capability of building objects with complex structures for small-batch production, and raw material versatility. There are several sub-categories of AM, among which is fused filament fabrication (FFF), also commonly known as fused deposition modeling (FDM). FFF has been one of the most widely used additive manufacturing techniques due to its cost-efficiency, simplicity, and widespread availability. The FFF process is mainly used to create 3D parts made of thermoplastic polymers, and complex physical phenomena such as melt flow, heat transfer, solidification, crystallization, etc. are involved in the FFF process. Different techniques have been developed and employed to analyze these phenomena, including experimental, analytical, numerical, and finite element analysis (FEA). This study specifically aims to provide a comprehensive review of the developed numerical models and simulation tools used to analyze melt flow behavior, heat transfer, crystallization and solidification kinetics, structural analysis, and the material characterization of polymeric components in the FFF process. The strengths and weaknesses of these numerical models are discussed, simplifications and assumptions are highlighted, and an outlook on future work in the numerical modeling and FE simulation of FFF is provided.
Citation: Materials
PubDate: 2024-08-23
DOI: 10.3390/ma17174185
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4186: Selective Extraction of Valuable and
Critical Metals in Cassiterite Concentrate by Dry Chlorination, Part I:
Thermodynamic and Modelling Perspective
Authors: Allen Yushark Fosu, Bastien Demeusy, Frédéric Diot, Tiina Lavonen, Veronika Meriläinen, Danièle Bartier, Yann Foucaud, Ndue Kanari
First page: 4186
Abstract: The chlorination of oxides of major concern in cassiterite concentrate with various chlorinating agents is investigated in light of their thermodynamic feasibilities to extract and recover their valuable metal components. Mechanisms responsible for the processes and their Gibbs free energy changes as a function of temperature to selectively separate and/or recover the metal(s) of interest and unwanted ones as their metallic chlorides are identified. Attention is given to gaseous (Cl2 and Cl2 + CO mixture) and solid (CaCl2 and MgCl2) chlorine sources, from which Cl2 + CO shows no reaction selectivity for any of the oxides but a feasible metal chloride formation for all. Chlorine gas (Cl2), on the other hand, could selectively form chlorides with metals of +2 oxidation state in their oxides, leaving those of high oxidation state unreacted. MgCl2, unlike CaCl2, is found capable of producing calcium, ferrous, and stannic chloride from their metallic oxides with enhanced reaction tendencies in the presence of silicon dioxide (SiO2). An overall study of the thermodynamic feasibility of all chlorine sources looked at alongside operational and environmental viabilities suitably suggests MgCl2 for a selective extraction of the valuable metal components in a cassiterite concentrate, in which case, moderate temperatures seem promising.
Citation: Materials
PubDate: 2024-08-23
DOI: 10.3390/ma17174186
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4187: Fabrication and Characterization of
Polycaprolactone–Baghdadite Nanofibers by Electrospinning Method for
Tissue Engineering Applications
Authors: Mir Reza Forogh, Rahmatollah Emadi, Mehdi Ahmadian, Abdollah Saboori
First page: 4187
Abstract: This work investigates the essential constituents, production methods, and properties of polycaprolactone (PCL) and Baghdadite fibrous scaffolds. In this research, electrospinning was used to produce fiber ropes. In this study, the Baghdadite powder was synthesized using the sol–gel method and incorporated into PCL’s polymeric matrix in formic acid and acetic acid solvents. The present work examined PCL–Baghdadite fibrous scaffolds at 1%, 3%, and 5 wt% for morphology, fiber diameter size, hydrophilicity, porosity, mechanical properties, degradability, and bioactivity. The introduction of Baghdadite nanopowder into pure PCL scaffolds reduced fiber diameter. The wetting angle decreased when Baghdadite nanopowder was added to fibrous scaffolds. Pure PCL reduced the wetting angle from 93.20° to 70.53°. Fibrous PCL scaffolds with Baghdadite nanopowder have better mechanical characteristics. The tensile strength of pure PCL fibers was determined at 2.08 ± 0.2 MPa, which was enhanced by up to 3 wt% by adding Baghdadite nanopowder. Fiber elasticity increased with tensile strength. Baghdadite at a 5% weight percentage reduced failure strain percentage. Fibers with more Baghdadite nanopowder biodegrade faster. Adding Baghdadite ceramic nanoparticles resulted in increased bioactivity and caused scaffolds to generate hydroxyapatite. The results show that Baghdadite PCL-3 wt% fibers have promising shape, diameter, and mechanical qualities. After 24 h, L-929 fibroblast cell viability was greater in the scaffold with 3% Baghdadite weight compared to the pure PCL. PCL-3 wt% Baghdadite fibers generated hydroxyapatite on the surface and degraded well. Based on the above findings, PCL fibers having 3 wt% of Baghdadite are the best sample for tissue engineering applications that heal flaws.
Citation: Materials
PubDate: 2024-08-23
DOI: 10.3390/ma17174187
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4188: An Investigation of the Photonic
Application of TeO2-K2TeO3-Nb2O5-BaF2 Glass Co-Doped with Er2O3/Ho2O3 and
Er2O3/Yb2O3 at 1.54 μm Based on Its Thermal and Luminescence Properties
Authors: Ahlem Boussetta, Aref M. Al-Syadi, Hasan B. Albargi, Kamel Damak, Ali Erçin Ersundu, Miray Çelikbilek Ersundu, Essam Ramadan, Ali M. Alshehri, Khalid I. Hussein, Ramzi Maalej, El Sayed Yousef
First page: 4188
Abstract: A glass composition using TeO2-K2TeO3-Nb2O5-BaF2 co-doped with Er2O3/Ho2O3 and Er2O3/Yb2O3 was successfully fabricated. Its thermal stability and physical parameters were studied, and luminescence spectroscopy of the fabricated glasses was conducted. The optical band gap, Eopt, decreased from 2.689 to 2.663 eV following the substitution of Ho2O3 with Yb2O3. The values of the refractive index, third-order nonlinear optical susceptibility (χ(3)), and nonlinear refractive index (n2) of the fabricated glasses were estimated. Furthermore, the Judd–Ofelt intensity parameters Ωt (t=2,4,6), radiative properties such as transition probabilities (Aed), magnetic dipole-type transition probabilities (Amd), branching ratios (β), and radiative lifetime (τ) of the fabricated glasses were evaluated. The emission cross-section and FWHM of the 4I13/2→4I15/2 transition around 1.54 μm of the glass were reported, and the emission intensity of the visible signal was studied under 980 nm laser excitation. The material might be a useful candidate for solid lasers and nonlinear amplifier devices, especially in the communications bands.
Citation: Materials
PubDate: 2024-08-23
DOI: 10.3390/ma17174188
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4189: Electrochemical Behavior of
Plasma-Nitrided Austenitic Stainless Steel in Chloride Solutions
Authors: Viera Zatkalíková, Petra Drímalová, Katarzyna Balin, Martin Slezák, Lenka Markovičová
First page: 4189
Abstract: The application possibilities of austenitic stainless steels in high friction, abrasion, and sliding wear conditions are limited by their inadequate hardness and tribological characteristics. In order to improve these properties, the thermochemical treatment of their surface by plasma nitriding is suitable. This article is focused on the corrosion resistance of conventionally plasma-nitrided AISI 304 stainless steel (530 °C, 24 h) in 0.05 M and 0.5 M sodium chloride solutions at room temperature (20 ± 3 °C), tested by potentiodynamic polarization and electrochemical impedance spectroscopy. Optical microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy are used for nitrided layer characterization. The experiment results confirmed the plasma-nitrided layer formation of increased micro-hardness related to the presence of Cr2N chromium nitrides and higher surface roughness compared to the as-received state. Both of the performed independent electrochemical corrosion tests point to a significant reduction in corrosion resistance after the performed plasma nitriding, even in a solution with a very low chloride concentration (0.05 mol/L).
Citation: Materials
PubDate: 2024-08-24
DOI: 10.3390/ma17174189
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4190: Microstructure and Properties of
Mg-Gd-Y-Zn-Mn High-Strength Alloy Welded by Friction Stir Welding
Authors: Jinxing Wang, Zhicheng Wan, Xiyu Wang, Jiaxu Wang, Yi Zou, Jingfeng Wang, Fusheng Pan
First page: 4190
Abstract: Mg-Gd-Y-Zn-Mn (MVWZ842) is a kind of high rare earth magnesium alloy with high strength, high toughness and multi-scale strengthening mechanisms. After heat treatment, the maximum tensile strength of MVWZ842 alloy is more than 550 MPa, and the elongation is more than 5%. Because of its great mechanical properties, MVWZ842 has broad application potential in aerospace and rail transit. However, the addition of high rare earth elements makes the deformation resistance of MVWZ842 alloy increase to some extent. This leads to the difficulty of direct plastic processing forming and large structural part shaping. Friction stir welding (FSW) is a convenient fast solid-state joining technology. When FSW is used to weld MVWZ842 alloy, small workpieces can be joined into a large one to avoid the problem that large workpieces are difficult to form. In this work, a high-quality joint of MVWZ842 alloy was achieved by FSW. The microstructure and properties of this high-strength magnesium alloy after friction stir welding were studied. There was a prominent onion ring characteristic in the nugget zone. After the base was welded, the stacking fault structure precipitated in the grain. There were a lot of broken long period stacking order (LPSO) phases on the retreating side of the nugget zone, which brought the effect of precipitation strengthening. Nano-α-Mn and the broken second phase dispersed in the matrix in the nugget zone, which made the grains refine. A relatively complete dynamic recrystallization occurred in the nugget zone, and the grains were refined. The welding coefficient of the welded joint exceeded 95%, and the hardness of the weld nugget zone was higher than that of the base. There were a series of strengthening mechanisms in the joint, mainly fine grain strengthening, second phase strengthening and solid solution strengthening.
Citation: Materials
PubDate: 2024-08-24
DOI: 10.3390/ma17174190
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4191: Bio-Inspired Curved-Elliptical Lattice
Structures for Enhanced Mechanical Performance and Deformation Stability
Authors: Zhengmiao Guo, Fan Yang, Lingbo Li, Jiacheng Wu
First page: 4191
Abstract: Lattice structures, characterized by their lightweight nature, high specific mechanical properties, and high design flexibility, have found widespread applications in fields such as aerospace and automotive engineering. However, the lightweight design of lattice structures often presents a trade-off between strength and stiffness. To tackle this issue, a bio-inspired curved-elliptical (BCE) lattice is proposed to enhance the mechanical performance and deformation stability of three-dimensional lattice structures. BCE lattice specimens with different parameters were fabricated using selective laser melting (SLM) technology, followed by quasi-static compression tests. Finite element (FE) numerical simulations were also carried out for validation. The results demonstrate that the proposed BCE lattice structures exhibit stronger mechanical performance and more stable deformation modes that can be adjusted through parameter tuning. Specifically, by adjusting the design parameters, the BCE lattice structure can exhibit a bending-dominated delocalized deformation mode, avoiding catastrophic collapse during deformation. The specific energy absorption (SEA) can reach 24.6 J/g at a relative density of only 8%, with enhancements of 48.5% and 297.6% compared with the traditional energy-absorbing lattices Octet and body-center cubic (BCC), respectively. Moreover, the crushing force efficiency (CFE) of the BCE lattice structure surpasses those of Octet and BCC by 34.9% and 15.8%, respectively. Through a parametric study of the influence of the number of peaks N and the curve amplitude A on the compression performance of the BCE lattice structure, the compression deformation mechanism is further analyzed. The results indicate that the curve amplitude A and the number of peaks N have significant impacts on the deformation mode of the BCE lattice. By adjusting the parameters N and A, a structure with a combination of high energy absorption, high stiffness, and strong fracture resistance can be obtained, integrating the advantages of tensile-dominated and bending-dominated lattice structures.
Citation: Materials
PubDate: 2024-08-24
DOI: 10.3390/ma17174191
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4192: Molecular Dynamics Simulations Guide the
Gasification Process of Carbon-Supported Nickel Catalysts in Biomass
Supercritical Water
Authors: Yuhui Wu, Liang Wu, Fan Liu, Yue Qiu, Runqiu Dong, Jingwei Chen, Daoxiu Liu, Le Wang, Lei Yi
First page: 4192
Abstract: In this study, the Density Functional Theory (DFT) Calculations for Molecules and Clusters—ADF module is employed to model carbon-supported nickel catalysts and lignin monomers, integrating the ReaxFF module to simulate molecular dynamics under supercritical water conditions, with a focus on lignin decomposition reactions. Molecular dynamics models for supercritical water gasification are established under various conditions such as catalyst presence, water molecule quantities, and reaction temperature. By comparing simulation systems under different conditions, the yields of and variations in combustible gases (hydrogen and carbon monoxide) are summarized. Introducing heteroatoms into the lattice of the carbon support can alter the electronic structure within graphene, thereby influencing its electrical and electrochemical properties, increasing the number of active sites, and significantly enhancing electrocatalytic activity. Simulation results indicate that carbon-supported nickel metal catalysts can promote the cleavage of C–C bonds in lignin monomers, thereby increasing the rate of water–gas shift reactions and boosting hydrogen production in the system by 105%. Increasing water molecule quantities favored water–gas shift reactions and hydrogen generation while lowering carbon monoxide formation. Moreover, elevating reaction temperatures led to increased hydrogen and carbon monoxide production rates, which were particularly pronounced between 2500 K and 3500 K. These findings offer crucial theoretical insights for advancing efficient hydrogen production through biomass supercritical water gasification.
Citation: Materials
PubDate: 2024-08-24
DOI: 10.3390/ma17174192
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4193: Predicting Sodium-Ion Battery Performance
through Surface Chemistry Analysis and Textural Properties of
Functionalized Hard Carbons Using AI
Authors: Walter M. Warren-Vega, Ana I. Zárate-Guzmán, Francisco Carrasco-Marín, Guadalupe Ramos-Sánchez, Luis A. Romero-Cano
First page: 4193
Abstract: Traditionally, the performance of sodium-ion batteries has been predicted based on a single characteristic of the electrodes and its relationship to specific capacity increase. However, recent studies have shown that this hypothesis is incorrect because their performance depends on multiple physical and chemical variables. Due to the above, the present communication shows machine learning as an innovative strategy to predict the performance of functionalized hard carbon anodes prepared from grapefruit peels. In this sense, a three-layer feed-forward Artificial Neural Network (ANN) was designed. The inputs used to feed the ANN were the physicochemical characteristics of the materials, which consisted of mercury intrusion porosimetry data (SHg and average pore), elemental analysis (C, H, N, S), ID/IG ratio obtained from RAMAN studies, and X-ray photoemission spectroscopy data of the C1s, N1s, and O1s regions. In addition, two more inputs were added: the cycle number and the applied C-rate. The ANN architecture consisted of a first hidden layer with a sigmoid transfer function and a second layer with a log-sigmoid transfer function. Finally, a sigmoid transfer function was used in the output layer. Each layer had 10 neurons. The training algorithm used was Bayesian regularization. The results show that the proposed ANN correctly predicts (R2 > 0.99) the performance of all materials. The proposed strategy provides critical insights into the variables that must be controlled during material synthesis to optimize the process and accelerate progress in developing tailored materials.
Citation: Materials
PubDate: 2024-08-24
DOI: 10.3390/ma17174193
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4194: Property Enhancement of Recycled Coarse
Aggregate and Its Concrete under CO2-Accelerated Curing Treatment
Authors: Yingying Li, Jia Long, Xiang Chen
First page: 4194
Abstract: The poor properties of recycled coarse aggregate (RCA) and recycled coarse aggregate concrete (RCAC) are considered key constraints hindering the reuse of this waste resource in marine engineering. The CO2-based accelerated carbonation method, which utilizes the alkali aggregate properties of RCA to achieve CO2 uptake and sequestration while significantly enhancing its properties, has attracted widespread attention. However, the degree of improvement in the properties of RCA under different initial moisture conditions (IMCs) and aggregate particle sizes (APSs) after CO2-accelerated carbonation remains unclear. Moreover, the quantitative effect of carbonated recycled coarse aggregate (CRCA), which is obtained from RCA samples with the optimal initial moisture conditions, on the improvement of RCAC under optimal accelerated carbonation modification conditions still needs to be studied in depth. For this investigation, a CO2-accelerated carbonation experiment was carried out on RCA samples with different IMCs and APSs, and the variations in the properties of RCA with respect to its IMC and APS were assessed. The degree of accelerated carbonation modification of RCA under different IMCs and APSs was quantified, and the optimal initial moisture conditions for enhancing the properties of the RCA were confirmed. By preparing concrete specimens based on the natural coarse aggregate, RCA, and CRCA with the best initial moisture conditions (considering the same concrete–water proportion), the effect of CRCA on the workability, mechanical properties, and durability of the corresponding concrete specimen was determined. The findings of this study can be used to effectively promote the sustainable development of marine science and engineering in the future and contribute to global dual-carbon goals, which are of great practical significance and scientific value.
Citation: Materials
PubDate: 2024-08-24
DOI: 10.3390/ma17174194
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4195: Growth of Single Crystals of
(K1−xNax)NbO3 by the Self-Flux Method and Characterization of Their
Phase Transitions
Authors: Doan Thanh Trung, Eugenie Uwiragiye, Tran Thi Lan, John G. Fisher, Jong-Sook Lee, Jungwi Mok, Junseong Lee, Furqan Ul Hassan Naqvi, Jae-Hyeon Ko
First page: 4195
Abstract: In this study, single crystals of (K1−xNax)NbO3 are grown by the self-flux crystal growth method and their phase transitions are studied using a combination of Raman scattering and impedance spectroscopy. X-ray diffraction shows that single crystals have a perovskite structure with monoclinic symmetry. Single crystal X-ray diffraction shows that single crystals have monoclinic symmetry at room temperature with space group P1211. Electron probe microanalysis shows that single crystals are Na-rich and A-site deficient. Temperature-controlled Raman scattering shows that low temperature monoclinic-monoclinic, monoclinic-tetragonal and tetragonal-cubic phase transitions take place at −20 °C, 220 °C and 440 °C. Dielectric property measurements show that single crystals behave as a normal ferroelectric material. Relative or inverse relative permittivity peaks at ~−10 °C, ~230 °C and ~450 °C with hysteresis correspond to the low temperature monoclinic-monoclinic, monoclinic-tetragonal and tetragonal-cubic phase transitions, respectively, consistent with the Raman scattering results. A conduction mechanism with activation energies of about 0.5–0.7 eV was found in the paraelectric phase. Single crystals show polarization-electric field hysteresis loops of a lossy normal ferroelectric. The combination of Raman scattering and impedance spectroscopy is effective in determining the phase transition temperatures of (K1−xNax)NbO3.
Citation: Materials
PubDate: 2024-08-24
DOI: 10.3390/ma17174195
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4196: Cutting-Edge Perovskite-Based Flexible
Pressure Sensors Made Possible by Piezoelectric Innovation
Authors: Adeela Naz, Yuan Meng, Jingjing Luo, Imtiaz Ahmad Khan, Rimsha Abbas, Suzhu Yu, Jun Wei
First page: 4196
Abstract: In the area of flexible electronics, pressure sensors are a widely utilized variety of flexible electronics that are both indispensable and prevalent. The importance of pressure sensors in various fields is currently increasing, leading to the exploration of materials with unique structural and piezoelectric properties. Perovskite-based materials are ideal for use as flexible pressure sensors (FPSs) due to their flexibility, chemical composition, strain tolerance, high piezoelectric and piezoresistive properties, and potential integration with other technologies. This article presents a comprehensive study of perovskite-based materials used in FPSs and discusses their components, performance, and applications in detecting human movement, electronic skin, and wireless monitoring. This work also discusses challenges like material instability, durability, and toxicity, the limited widespread application due to environmental factors and toxicity concerns, and complex fabrication and future directions for perovskite-based FPSs, providing valuable insights for researchers in structural health monitoring, physical health monitoring, and industrial applications.
Citation: Materials
PubDate: 2024-08-24
DOI: 10.3390/ma17174196
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4197: Effect of Coherent Nanoprecipitate on
Strain Hardening of Al Alloys: Breaking through the Strength-Ductility
Trade-Off
Authors: Pan Wu, Kexing Song, Feng Liu
First page: 4197
Abstract: So-called strength-ductility trade-off is usually an inevitable scenario in precipitation-strengthened alloys. To address this challenge, high-density coherent nanoprecipitates (CNPs) as a microstructure effectively promote ductility though multiple interactions between CNPs and dislocations (i.e., coherency, order, or Orowan mechanism). Although some strain hardening theories have been reported for individual strengthening, how to increase, artificially and quantitatively, the ductility arising from cooperative strengthening due to the multiple interactions has not been realized. Accordingly, a dislocation-based theoretical framework for strain hardening is constructed in terms of irreversible thermodynamics, where nucleation, gliding, and annihilation arising from dislocations have been integrated, so that the cooperative strengthening can be treated through thermodynamic driving force ∆G and the kinetic energy barrier. Further combined with synchrotron high-energy X-ray diffraction, the current model is verified. Following the modeling, the yield stress σy is proved to be correlated with the modified strengthening mechanism, whereas the necking strain εn is shown to depend on the evolving dislocation density and, essentially, the enhanced activation volume. A criterion of high ∆G-high generalized stability is proposed to guarantee the volume fraction of CNPs improving σy and the radius of CNPs accelerating εn. This strategy of breaking the strength-ductility trade-off phenomena by controlling the cooperative strengthening can be generalized to designing metallic structured materials.
Citation: Materials
PubDate: 2024-08-24
DOI: 10.3390/ma17174197
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4198: Assessing the Impact of Drought Stress on
Hemp (Cannabis sativa L.) Fibers
Authors: Edyta Kwiatkowska, Małgorzata Zimniewska, Wanda Różańska, Michał Puchalski, Patrycja Przybylska
First page: 4198
Abstract: Drought can significantly impact fiber crop cultivation due to the plants’ specific water requirements and their extended vegetative period. The purpose of the research was to examine how drought stress affects the quality and chemical composition of hemp (Cannabis sativa L.) fibers. A three-year pot experiment was conducted in a plant growth facility, using controlled drought stress for hemp plants. Soil moisture levels were maintained at three levels, where 45% field water capacity was the control and 35% and 25% FWC were drought. A comprehensive suite of fiber quality characterization techniques, including linear density measurement, tenacity assessment, Fourier Transform Infrared Spectroscopy (FTIR), and Wide-Angle X-ray Diffraction (WAXD), was employed to evaluate the impact of drought stress on fiber properties. The chemical composition of hemp fibers was thoroughly analyzed, quantifying the content of cellulose, hemicellulose, pectin, and lignin. The findings indicate that drought conditions significantly influence linear density, wax and fat content, as well as the crystallinity of the fibers.
Citation: Materials
PubDate: 2024-08-24
DOI: 10.3390/ma17174198
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4199: Enhancing Wound Healing: A Comprehensive
Review of Sericin and Chelidonium majus L. as Potential Dressings
Authors: Ana Borges, María Luisa Martín Calvo, Josiana A. Vaz, Ricardo C. Calhelha
First page: 4199
Abstract: Wound healing, a complex physiological process orchestrating intricate cellular and molecular events, seeks to restore tissue integrity. The burgeoning interest in leveraging the therapeutic potential of natural substances for advanced wound dressings is a recent phenomenon. Notably, Sericin, a silk-derived protein, and Chelidonium majus L. (C. majus), a botanical agent, have emerged as compelling candidates, providing a unique combination of natural elements that may revolutionize conventional wound care approaches. Sericin, renowned for its diverse properties, displays unique properties that accelerate the wound healing process. Simultaneously, C. majus, with its diverse pharmacological compounds, shows promise in reducing inflammation and promoting tissue regeneration. As the demand for innovative wound care solutions increases, understanding the therapeutic potential of natural products becomes imperative. This review synthesizes current knowledge on Sericin and C. majus, envisioning their future roles in advancing wound management strategies. The exploration of these natural substances as constituents of wound dressings provides a promising avenue for developing sustainable, effective, and biocompatible materials that could significantly impact the field of wound healing.
Citation: Materials
PubDate: 2024-08-24
DOI: 10.3390/ma17174199
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4200: Thermal Relaxation in Janus Transition
Metal Dichalcogenide Bilayers
Authors: Aristotelis P. Sgouros, Fotios I. Michos, Michail M. Sigalas, George Kalosakas
First page: 4200
Abstract: In this work, we employ molecular dynamics simulations with semi-empirical interatomic potentials to explore heat dissipation in Janus transition metal dichalcogenides (JTMDs). The middle atomic layer is composed of either molybdenum (Mo) or tungsten (W) atoms, and the top and bottom atomic layers consist of sulfur (S) and selenium (Se) atoms, respectively. Various nanomaterials have been investigated, including both pristine JTMDs and nanostructures incorporating inner triangular regions with a composition distinct from the outer bulk material. At the beginning of our simulations, a temperature gradient across the system is imposed by heating the central region to a high temperature while the surrounding area remains at room temperature. Once a steady state is reached, characterized by a constant energy flux, the temperature control in the central region is switched off. The heat attenuation is investigated by monitoring the characteristic relaxation time (τav) of the local temperature at the central region toward thermal equilibrium. We find that SMoSe JTMDs exhibit thermal attenuation similar to conventional TMDs (τav~10–15 ps). On the contrary, SWSe JTMDs feature relaxation times up to two times as high (τav~14–28 ps). Forming triangular lateral heterostructures in their surfaces leads to a significant slowdown in heat attenuation by up to about an order of magnitude (τav~100 ps).
Citation: Materials
PubDate: 2024-08-25
DOI: 10.3390/ma17174200
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4201: Mechanical and Drying Shrinkage
Performance Study of Ultra-High-Performance Concrete Prepared from
Titanium Slag under Different Curing Conditions
Authors: Jinxin Wang, Jun Li, Yan Gao, Zhongyuan Lu, Li Hou
First page: 4201
Abstract: This research investigates the effects of various curing regimes, the incorporation of titanium slag, and the utilization of quartz sand on the strength properties and shrinkage behavior of ultra-high-performance concrete (UHPC). By using low-heat silicate cement to prepare UHPC, this study conducted standard curing and steam curing, and comprehensively analyzed the macro and micro performance of UHPC under different curing conditions. The findings indicate that the application of steam curing markedly enhances the mechanical attributes of UHPC while efficiently decreasing its drying shrinkage. In the comparative tests, we found that the compressive strength of concrete that had undergone 2 days of steam curing was 9.15% higher than that of concrete cured for 28 days under standard conditions. In addition, under the same curing conditions, titanium slag sand had higher mechanical properties than quartz sand. Under standard curing conditions, the 28-day compressive strength of UHPC using titaniferous slag aggregate was 12.64% higher than that of UHPC using standard sand. Through the data analysis of XRD, TG, and MIP, we found that the content of Ca(OH)2 in the hydration products after steam curing was reduced compared to the standard curing conditions, and the pore structure had been optimized. The UHPC prepared with titanium slag sand has greater advantages in mechanical properties and drying shrinkage, and has a smaller pore structure than the UHPC prepared with quartz sand. Moreover, the use of titanium slag sand offers ecological and economic benefits, making it a more sustainable and cost-effective option for high-performance construction applications.
Citation: Materials
PubDate: 2024-08-25
DOI: 10.3390/ma17174201
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4202: Zirconia Dental Implant Designs and
Surface Modifications: A Narrative Review
Authors: Michał Ciszyński, Bartosz Chwaliszewski, Wojciech Simka, Marzena Dominiak, Tomasz Gedrange, Jakub Hadzik
First page: 4202
Abstract: Titanium currently has a well-established position as the gold standard for manufacturing dental implants; however, it is not free of flaws. Mentions of possible soft-tissue discoloration, corrosion, and possible allergic reactions have led to the development of zirconia dental implants. Various techniques for the surface modification of titanium have been applied to increase titanium implants’ ability to osseointegrate. Similarly, to achieve the best possible results, zirconia dental implants have also had their surface modified to promote proper healing and satisfactory long-term results. Despite zirconium oxide being a ceramic material, not simply a metal, there have been mentions of it being susceptible to corrosion too. In this article, we aim to review the literature available on zirconia implants, the available techniques for the surface modification of zirconia, and the effects of these techniques on zirconia’s biological properties. Zirconia’s biocompatibility and ability to osseointegrate appears unquestionably good. Despite some of its mechanical properties being, factually, inferior to those of titanium, the benefits seem to outweigh the drawbacks. Zirconia implants show very good success rates in clinical research. This is partially due to available methods of surface treatment, including nanotopography alterations, which allow for improved wettability, bone-to-implant contact, and osteointegration in general.
Citation: Materials
PubDate: 2024-08-25
DOI: 10.3390/ma17174202
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4203: Small Punch Testing of a Ti6Al4V Titanium
Alloy and Simulations under Different Stress Triaxialities
Authors: Kun Wang, Xilong Zhao, Zeyu Cao
First page: 4203
Abstract: The mechanical properties of local materials subjected to various stress triaxialities were investigated via self-designed small punch tests and corresponding simulations, which were tailored to the geometry and notch forms of the samples. The finite element model was developed on the basis of the actual test method. After verifying the accuracy of the simulation, the stress, strain, and void volume fraction distributions of the Ti6Al4V titanium alloy under different stress states were compared and analyzed. The results indicate that the mechanical properties of the local material significantly differ during downward pressing depending on the geometric shape. A three-dimensional tensile stress state was observed in the center area, where the void volume fraction was greater than the fracture void volume fraction. The fracture morphology of the samples further confirmed the presence of different stress states. Specifically, the fracture morphology of the globular head samples (with or without U-shaped notches) predominantly featured dimples. Modifying the specimen’s geometry effectively increased stress triaxiality, facilitating the determination of the material’s constitutive relationship under varying stress states.
Citation: Materials
PubDate: 2024-08-25
DOI: 10.3390/ma17174203
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4204: Research Progress and Emerging Directions
in Stimulus Electro-Responsive Polymer Materials
Authors: Zifeng Jin, Xiaoyan Wei, Xiaojun He, Zhenglin Wang, Zhibo Zhao, Huan He, Ya’nan Yang, Nan Chen
First page: 4204
Abstract: Stimulus electro-responsive polymer materials can reversibly change their physical or chemical properties under various external stimuli such as temperature, light, force, humidity, pH, and magnetic fields. This review introduces typical conventional stimulus electro-responsive polymer materials and extensively explores novel directions in the field, including multi-stimuli electro-responsive polymer materials and humidity electro-responsive polymer materials pioneered by our research group. Despite significant advancements in stimulus electro-responsive polymer materials, ongoing research focuses on enhancing their efficiency, lifespan, and production costs. Interdisciplinary collaboration and advanced technologies promise to broaden the application scope of these materials, particularly in medical and environmental protection fields, ultimately benefiting society.
Citation: Materials
PubDate: 2024-08-25
DOI: 10.3390/ma17174204
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4205: Investigating the Effect of Perforations
on the Load-Bearing Capacity of Cardboard Packaging
Authors: Kacper Andrzejak, Damian Mrówczyński, Tomasz Gajewski, Tomasz Garbowski
First page: 4205
Abstract: The impact of perforation patterns on the compressive strength of cardboard packaging is a critical concern in the packaging industry, where optimizing material usage without compromising structural integrity is essential. This study aims to investigate how different perforation designs affect the load-bearing capacity of cardboard boxes. Utilizing finite element method (FEM) simulations, we assessed the compressive strength of packaging made of various types of corrugated cardboards, including E, B, C, EB, and BC flutes with different heights. Mechanical testing was conducted to obtain accurate material properties for the simulations. Packaging dimensions were varied to generalize the findings across different sizes. Results showed that perforation patterns significantly influenced the compressive strength, with reductions ranging from 14% to 43%, compared to non-perforated packaging. Notably, perforations on multiple walls resulted in the highest strength reductions. The study concludes that while perforations are necessary for functionality and aesthetics, their design must be carefully considered to minimize negative impacts on structural integrity. These findings provide valuable insights for designing more efficient and sustainable packaging solutions in the industry.
Citation: Materials
PubDate: 2024-08-25
DOI: 10.3390/ma17174205
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4206: Microstructure-Based Flow Stress Model to
Predict Machinability of Inconel 718
Authors: Qingan Yin, Hui Chen, Jianxiong Chen, Yu Xie, Ming Shen, Yuhua Huang
First page: 4206
Abstract: Due to its exceptional mechanical and chemical properties at high temperatures, Inconel 718 is extensively utilized in industries such as aerospace, aviation, and marine. Investigating the flow behavior of Inconel 718 under high strain rates and high temperatures is vital for comprehending the dynamic characteristics of the material in manufacturing processes. This paper introduces a physics-based constitutive model that accounts for dislocation motion and its density evolution, capable of simulating the plastic behavior of Inconel 718 during large strain deformations caused by machining processes. Utilizing a microstructure-based flow stress model, the machinability of Inconel 718 in terms of cutting forces and temperatures is quantitatively predicted and compared with results from orthogonal cutting experiments. The model’s predictive precision, with a margin of error between 5 and 8%, ensures reliable consistency and enhances our comprehension of the high-speed machining dynamics of Inconel 718 components.
Citation: Materials
PubDate: 2024-08-25
DOI: 10.3390/ma17174206
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4207: Neomycin Intercalation in Montmorillonite:
The Role of Ion Exchange Capacity and Process Conditions
Authors: Alicja Rapacz-Kmita, Marcin Gajek, Magdalena Dudek, Roksana Kurpanik, Stanisława Kluska, Ewa Stodolak-Zych
First page: 4207
Abstract: The study examined the possibility of intercalation of montmorillonite with neomycin in an aqueous drug solution and the factors influencing the effectiveness of this process, such as the ion exchange capacity and process conditions, including the time and temperature of incubation with the drug. X-ray diffractometry (XRD), infrared spectroscopy (FTIR), thermal analysis (DSC/TG), and Zeta potential measurement were used to confirm drug intercalation as well as to investigate the nature of clay–drug interactions. The obtained conjugates with the most favorable physicochemical properties were also tested for antibacterial response against Gram-negative bacteria (Escherichia coli) to confirm that the bactericidal properties of neomycin were retained after intercalation and UV–VIS spectrophotometry was used to examine the kinetics of drug release from the carrier. The results of the conducted research clearly indicate the successful intercalation of neomycin in montmorillonite and indicate the influence of process parameters on the properties of not only the conjugates themselves but also the properties of the intercalated drug, particularly its bactericidal activity. Ultimately, a temperature of 50 °C was found to be optimal for effective drug intercalation and the conjugates obtained within 2 h showed the highest antibacterial activity, indicating the highest potential of the thus-obtained montmorillonite conjugates as neomycin carriers.
Citation: Materials
PubDate: 2024-08-25
DOI: 10.3390/ma17174207
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4208: On the Aptness of Material Constitutive
Models for Simulating Nano-Scratching Processes
Authors: Hao Shen, Sivakumar Kulasegaram, Emmanuel Brousseau
First page: 4208
Abstract: The simulation of nano-scratching on metallic substrates using smooth particle hydrodynamics (SPH) has been attempted by researchers in recent years. From a review of the existing SPH simulations of nano-scratching processes, it was found that mainly two different material constitutive models (i.e., the Johnson–Cook model and the elasto-plastic model) were employed to describe the material flow. In the majority of these investigations, the Johnson–Cook model was employed to characterise the stress flow of the material subjected to scratching. A natural question remains as to which material constitutive model is preferable for the SPH modelling of nano-scratching when quantitatively predicting the process outcomes. In this paper, a quantitative comparison of material responses during the nano-scratching of copper is reported when the process is simulated using SPH with two different constitutive material models, namely the Johnson–Cook and the elasto-plastic models. In particular, the simulated cutting and normal forces as well as the machined topography using both approaches are compared with the experimental work reported in the literature. The SPH-based simulation results in this paper are investigated based on the following three aspects: (a) cutting and normal forces with different material models and depths of the cut, (b) the effect of the cutting speed on forces and its dependence on adopted material models, and (c) the effect of adopted material models on the surface topography of machined nano-grooves. The SPH simulation results showed that using the Johnson–Cook material model, cutting and normal forces were closer to the experimental data compared to the results obtained with the elasto-plastic model. The results also showed that the cross-sectional profile of simulated nano-grooves using the Johnson–Cook model was closer to the experimental results. Overall, this paper shows that the selection of the Johnson–Cook model is preferable for the SPH modelling of the nano-scratching process.
Citation: Materials
PubDate: 2024-08-25
DOI: 10.3390/ma17174208
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4209: Effect of Carboxymethyl Cellulose and
Polyvinyl Alcohol on the Dispersibility and Chemical Functional Group of
Nonwoven Fabrics Composed of Recycled Carbon Fibers
Authors: Kyungeun Kim, Gyungha Kim, Daeup Kim
First page: 4209
Abstract: In this study, recycled carbon fibers (rCFs) recovered from waste carbon composites were used to manufacture wet-laid nonwoven fabrics. The aim was to improve dispersibility by investigating the changes in the dispersibility of carbon fibers (CFs) based on the content of the dispersant carboxymethyl cellulose (CMC) and the binder polyvinyl alcohol (PVA), and the length and basis weight of the CFs. In addition, the chemical property changes and oxygen functional group mechanisms based on the content of the CMC dispersant and PVA binder were investigated. The nonwoven fabrics made with desized CFs exhibited significantly improved dispersibility. For nonwoven fabrics produced with a fixed binder PVA content of 10%, optimal dispersibility was achieved at a dispersant CMC concentration of 0.4%. When the dispersant CMC concentration was fixed at 0.4% and the binder PVA content at 10%, the best dispersibility was observed at a CF length of 3 mm, while the maximum tensile strength was achieved at a fiber length of 6 mm. Dispersibility remained almost consistent across different basis weights. As the dispersant CMC concentration increased from 0.2% to 0.6%, the oxygen functional groups, such as carbonyl group (C=O), lactone group (O=C-O), and natrium hydroxide (NaOH), also increased. However, hydroxyl group (C-O) decreased. Moreover, the contact angle decreased, while the surface free energy increased. On the other hand, when the dispersant CMC concentration was fixed at 0.4%, the optimal binder PVA content was found to be 3%. As the binder PVA content increased from 0% to 10%, the formation of hydrogen bonds between the CMC dispersant and the PVA binder led to an increase in C=O and O=C-O bonds, while C-O and NaOH decreased. As the amount of oxygen increased, the contact angle decreased and the surface free energy increased.
Citation: Materials
PubDate: 2024-08-26
DOI: 10.3390/ma17174209
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4210: Finite Element Analysis of the Structure
and Working Principle of Solid-State Shear Milling (S3M) Equipment
Authors: Lingfei Wei, Chao Wang, Ruoxuan Duan, Zehang Zhou, Canhui Lu
First page: 4210
Abstract: Solid-state shear milling (S3M) equipment is an evolution from traditional stone mills, enabling the processing of polymer materials and fillers through crushing, mixing, and mechanochemical reactions at ambient temperature. Due to the complex structure of the mill-pan, empirical data alone are insufficient to give a comprehensive understanding of the physicochemical interactions during the milling process. To provide an in-depth insight of the working effect and mechanism of S3M equipment, finite element method (FEM) analysis is employed to simulate the milling dynamics, which substantiates the correlation between numerical outcomes and experimental observations. A model simplification strategy is proposed to optimize calculation time without compromising accuracy. The findings in this work demonstrate the S-S bond breakage mechanism behind stress-induced devulcanization and suggest the structural optimizations for enhancing the devulcanization and pulverization efficiency of S3M equipment, thereby providing a theoretical foundation for its application in material processing.
Citation: Materials
PubDate: 2024-08-26
DOI: 10.3390/ma17174210
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4211: Experimental Study on Heat Conduction and
Water Migration of Composite Bentonite Samples
Authors: Gaosheng Yang, Bing Bai, Wenxuan Chen, Haitao Mao, Zhonghua Liu, Xiaoling Lan
First page: 4211
Abstract: The joints of buffer material composite blocks as potential weak parts in the engineering barrier system of a high-level radioactive waste (HLW) repository must be studied in depth. Therefore, a laboratory experiment device suitable for unsaturated composite bentonite samples was developed. The evolution of temperature and volumetric water content at different locations of Gaomiaozi (GMZ) composite bentonite samples with time before and after simulated water inflow was measured by the experiment device. According to the experimental results, the thermal conductivity and hydraulic conductivity of the joint location after healing of the composite bentonite samples were obtained. The experimental results show that the change in the internal temperature of the composite bentonite samples is mainly affected by the temperature boundary and that the change in the internal water has little effect on it. In a short period of time, the loading of hydraulic boundary conditions only makes the volumetric water content of the soil near the hydraulic boundary increase significantly but has little effect on other locations. And, affected by the temperature boundary, the volumetric water content of the soil near the temperature boundary gradually decreases with time. The process of hydration swelling of the composite bentonite sample is accompanied by the adjustment of stress. The composite bentonite samples are continuously squeezed to the joint area after hydration swelling, the whole composite samples are generally homogenized, and the joints between the composite bentonite samples tend to heal. The thermal conductivity and permeability of the joint location after healing can meet the requirements of the engineering barrier of the HLW repository.
Citation: Materials
PubDate: 2024-08-26
DOI: 10.3390/ma17174211
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4212: Study of Ultra-High Performance Concrete
Mechanical Behavior under High Temperatures
Authors: Guilherme S. Sumitomo, Lia L. Pimentel, Ana Elisabete P. G. A. Jacintho, Nadia C. S. Forti
First page: 4212
Abstract: The main concern with concrete at high temperatures is loss of strength and explosive spalling, which are more pronounced in high-strength concretes, such as Ultra-High Performance Concrete (UHPC). The use of polymeric fibers in the mixture helps control chipping, increasing porosity and reducing internal water vapor pressure, but their addition can impact its mechanical properties and workability. This study evaluated the physical and mechanical properties of UHPC with metallic and PVA fibers under high temperatures using a 23 central composite factorial design. The consistency of fresh UHPC and the compressive strength and elasticity modulus of hardened UHPC were measured. Above 300 °C, both compressive strength and elasticity modulus decreased drastically. Although the addition of PVA fibers reduced fluidity, it decreased the loss of compressive strength after exposure to high temperatures. The response surface indicates that the ideal mixture—1.65% steel fiber and 0.50% PVA fiber—achieved the highest compressive strength, both at room temperature and at high temperatures. However, PVA fibers did not protect UHPC against explosive spalling at the levels used in this research.
Citation: Materials
PubDate: 2024-08-26
DOI: 10.3390/ma17174212
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4213: Synthesis and Characterization of Highly
Fluorinated Hydrophobic Rare–Earth Metal–Organic Frameworks
(MOFs)
Authors: Muhammad Abbas, Bhargavasairam Murari, Simin Sheybani, Monu Joy, Kenneth J. Balkus
First page: 4213
Abstract: Tuning a material’s hydrophobicity is desirable in several industrial applications, such as hydrocarbon storage, separation, selective CO2 capture, oil spill cleanup, and water purification. The introduction of fluorine into rare-earth (RE) metal–organic frameworks (MOFs) can make them hydrophobic. In this work, the linker bis(trifluoromethyl)terephthalic acid (TTA) was used to make highly fluorinated MOFs. The reaction of the TTA and RE3+ (RE: Y, Gd, or Eu) ions resulted in the primitive cubic structure (pcu) exhibiting RE dimer nodes (RE-TTA-pcu). The crystal structure of the RE-TTA-pcu was obtained. The use of the 2-fluorobenzoic acid in the synthesis resulted in fluorinated hexaclusters in the face-centered cubic (fcu) framework (RE-TTA-fcu), analogous to the UiO-66 MOF. The RE-TTA-fcu has fluorine on the linker as well as in the cluster. The MOFs were characterized by powder X-ray diffraction, X-ray photoelectron spectroscopy, thermogravimetric analysis, and contact angle measurements.
Citation: Materials
PubDate: 2024-08-26
DOI: 10.3390/ma17174213
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4214: Prediction of Rock Unloading Strength
Based on PSO-XGBoost Hybrid Models
Authors: Baohua Liu, Hang Lin, Yifan Chen, Chaoyi Yang
First page: 4214
Abstract: Rock excavation is essentially an unloading behavior, and its mechanical properties are significantly different from those under loading conditions. In response to the current deficiencies in the peak strength prediction of rocks under unloading conditions, this study proposes a hybrid learning model for the intelligent prediction of the unloading strength of rocks using simple parameters in rock unloading tests. The XGBoost technique was used to construct a model, and the PSO-XGBoost hybrid model was developed by employing particle swarm optimization (PSO) to refine the XGBoost parameters for better prediction. In order to verify the validity and accuracy of the proposed hybrid model, 134 rock sample sets containing various common rock types in rock excavation were collected from international and Chinese publications for the purpose of modeling, and the rock unloading strength prediction results were compared with those obtained by the Random Forest (RF) model, the Support Vector Machine (SVM) model, the XGBoost (XGBoost) model, and the Grid Search Method-based XGBoost (GS-XGBoost) model. Meanwhile, five statistical indicators, including the coefficient of determination (R2), mean absolute error (MAE), mean absolute percentage error (MAPE), mean square error (MSE), and root mean square error (RMSE), were calculated to check the acceptability of these models from a quantitative perspective. A review of the comparison results revealed that the proposed PSO-XGBoost hybrid model provides a better performance than the others in predicting rock unloading strength. Finally, the importance of the effect of each input feature on the generalization performance of the hybrid model was assessed. The insights garnered from this research offer a substantial reference for tunnel excavation design and other representative projects.
Citation: Materials
PubDate: 2024-08-26
DOI: 10.3390/ma17174214
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4215: Effect of Laser Power on Microstructure
and Properties of WC-12Co Composite Coatings Deposited by Laser-Based
Directed Energy Deposition
Authors: Wen Li, Husen Yang, Yichun Liu, Fengxian Li, Jianhong Yi, Jürgen Eckert
First page: 4215
Abstract: During the laser-based directed energy deposition (DED-LB) processing, a WC-12Co composite coating with high hardness and strong wear resistance was successfully prepared on a 316L stainless steel substrate by adopting a high-precision coaxial powder feeding system using a spherical WC-12Co composite powder, which showed a large number of dendritic carbides and herringbone planar crystals on the substrate-binding interface. The influences of laser power on microstructural and mechanical properties (e.g., hardness, friction resistance) of WC-12Co composite surfaces were investigated. The results show that laser power has a significant effect on determining the degree of Co phase melting around the WC particles and the adhesion strength between the matrix and the coating. Lower laser power does not meet the melting requirements of WC particles, thus weakening the molding quality of the composite coating. At high laser power, it is possible to dissolve the WC particles and melt the metal powder between the particles, thus improving the material properties. The laser power increased from 700 W to 1000 W and the average hardness of the coating surface gradually increased from 1166.33 HV to 1395.70 HV, which is about 4–5 times higher than the average hardness of the substrate (about 281.76 HV). In addition, the coatings deposited at 1000 W showed better wear resistance. This work shows that the processing parameters during laser-directed energy deposition can be optimized to prepare WC-12Co composite coatings with excellent mechanical properties.
Citation: Materials
PubDate: 2024-08-26
DOI: 10.3390/ma17174215
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4216: Analysis of the Suitability of Ultrasonic
Testing for Verification of Nonuniform Welded Joints of
Austenitic–Ferritic Sheets
Authors: Łukasz Rawicki, Ryszard Krawczyk, Jacek Słania, Grzegorz Peruń, Grzegorz Golański, Katarzyna Łuczak
First page: 4216
Abstract: The purpose of the presented research was to determine the suitability of using ultrasonic testing (UT) to inspect heterogeneous, from a material point of view, welded joints on the example of the joints of a ferritic steel element with elements made of an austenitic steel. The echo technique with transverse (SEK) and longitudinal wave heads (SEL) addressed this issue. Due to the widespread use of 13CrMo4-5 and X2CrNiMo17-12-2 steel grades in the energy industry, they were selected as the test materials for the study. The objects of the presented research were welded joint specimens with thicknesses of 8, 12, and 16 mm and dimensions of 300 × 300 mm, made using the 135 metal active gas (MAG) process with the use of the Lincoln 309LSi wire—a ferritic–austenitic filler material. The stages of the research task were (1) making distance–amplitude curve (DAC) patterns from the test materials; (2) preparation of specimens of welded joints with artificial discontinuities in the form of through-holes; (3) performing UT tests on welded joints with artificial discontinuities using heads with 60° and 70° angles for the transverse wave and angle heads for longitudinal waves with similar beam insertion angles; (4) selection, by radiographic testing (RT), of welded joint specimens with natural discontinuities in the form of a lack of sidewall fusion; (5) performing UT tests on welded joints with natural discontinuities, using heads as welded joints with artificial discontinuities. It was found that (1) the highest sensitivity of discontinuity detection was obtained by performing tests on the ferritic steel side, which is due to the lower attenuation of the ultrasonic wave propagating in ferritic steel compared to austenitic steel; (2) the best detection of discontinuities could be obtained using a longitudinal ultrasonic wave; (3) there is a relationship between the thickness of the welded elements, the angle of the ultrasonic beam introduction, and the effectiveness of discontinuity detection.
Citation: Materials
PubDate: 2024-08-26
DOI: 10.3390/ma17174216
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4217: Strongly Fluorescent Blue-Emitting La2O3:
Bi3+ Phosphor for Latent Fingerprint Detection
Authors: Hanen Douiri, Marwa Abid, Lamia Rzouga Haddada, Layla Brini, Alessandra Toncelli, Najoua Essoukri Ben Amara, Ramzi Maalej
First page: 4217
Abstract: Blue-emitting bismuth-doped lanthanum oxide (La2O3: Bi3+) with various concentrations of Bi was synthesized using the sol–gel combustion method and used for visualization of latent fingerprints (LFPs). An X-ray diffraction (XRD) study revealed the hexagonal structure of the phosphors and total incorporation of the bismuth in the La2O3 matrix. Field Emission Scanning Electron Microscopy (FE-SEM) and Fourier Transform Infrared Spectroscopy (FTIR) were used to study the morphology and the relative vibrations of the synthesized samples. Photoluminescence (PL) studies showed strong blue emission around 460 nm due to the 3P1 → 1S0 transition. Clear bright-blue fingerprint images were obtained with the powder dusting method on various surfaces like aluminum, compact discs, glass, wood and marble. A first evaluation of these images indicated a clear visualization of all three levels of details and a very high contrast ranging from 0.41 on marble to 0.90 on aluminum. As a further step, we used an algorithm for extracting fingerprint minutiae with which we succeeded in detecting all three levels of fingerprint details and even the most difficult ones, like open and closed pores. According to these analyses, La2O3: Bi phosphor is demonstrated to be an effective blue fluorescent powder for excellent visualization of latent fingerprints.
Citation: Materials
PubDate: 2024-08-26
DOI: 10.3390/ma17174217
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4218: Effect of Stöber Nano-SiO2 Particles
on the Hydration Properties of Calcined Coal Gangue-Blended Cement
Authors: Nan Zhang, Hao Zhou, Yueyang Hu, Jiaqing Wang, Guihua Hou, Jian Ma, Ruiyu Jiang
First page: 4218
Abstract: This study focuses on the calcined coal gangue (CCG)-blended cements containing Stöber nano-SiO2 (SNS) particles. The effects of SNS particles on the workability, hydration behaviour, mechanical properties and microstructure evolution of the blended cements were comprehensively investigated at curing ages ranging from 1 to 28 d. The hydration behaviour was studied via isothermal calorimetry test, X-ray diffraction (XRD) and thermogravimetric (TG) tests. The microstructural evolution was studied using mercury intrusion porosimetry (MIP) and scanning electron microscopy (SEM). The results show that the incorporation of SNS led to a significant reduction in fluidity, particularly at an SNS content of 3%. The SNS significantly increased the compressive strength of the CCG-blended cement at all curing ages, and the optimum SNS content was found to be 2%. SNS significantly accelerated not only the early cement hydration but also the pozzolanic reaction of CCG at later curing ages, resulting in a decrease in portlandite, as evidenced by the isothermal calorimetry, XRD and TG analysis. Microstructural analysis shows that the incorporation of SNS effectively refined the pore structure of the CCG-blended cement, resulting in the formation of a dense microstructure. All these beneficial effects of SNS provides advantages in the development of the compressive strength of the CCG-blended cement at all curing ages.
Citation: Materials
PubDate: 2024-08-26
DOI: 10.3390/ma17174218
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4219: Effect of Extrusion Ratio on Mechanical
Behavior and Microstructure Evolution of 7003 Aluminum Alloy at High-Speed
Impact
Authors: Rui Xing, Pengcheng Guo
First page: 4219
Abstract: The extrusion ratio (ER) is one of the most important factors affecting the service performance of aluminum profiles. In this study, the influence of ER on the mechanical behavior and microstructure evolution of 7003 aluminum alloy at high-speed impact with strain rates ranging from 700 s−1 to 1100 s−1 was investigated. The studied alloy with an ER of 56 formed coarse grain rings during the heat treatment. The microstructure of the alloys with ERs of 20 and 9 is relatively uniform. The results indicate that under high-speed impact, the mechanical response behavior of the 7003-T6 alloy with different ERs is different. For the alloy with an ER of 56, strain hardening is the main mechanism of plastic deformation. In contrast, a flow stress reduction occurs at middle deformation stage for the ones with ERs of 20 and 9 due to concentrated deformation, which is more significant in the alloy with an ER of 20. Under high-speed impact, the alloy with an ER of 56 undergoes uneven plastic deformation due to the presence of coarse grain rings. The deformation is mainly borne by the region of coarse grains near the edge, and the closer to the center, the smaller the deformation. The deformation of the alloys with ERs of 20 and 9 is relatively uniform, but exhibits localized concentrated deformation in the area near the edge. The significant plastic deformation within deformation band causes a local temperature rise, resulting in a slight decrease in flow stress after the peak. These results can provide reliable data support for the application of 7003 aluminum alloy in the vehicle body crash energy absorption structure.
Citation: Materials
PubDate: 2024-08-26
DOI: 10.3390/ma17174219
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4220: Polysaccharide-Based Composite Systems in
Bone Tissue Engineering: A Review
Authors: Karina Niziołek, Dagmara Słota, Agnieszka Sobczak-Kupiec
First page: 4220
Abstract: In recent years, a growing demand for biomaterials has been observed, particularly for applications in bone regenerative medicine. Bone tissue engineering (BTE) aims to develop innovative materials and strategies for repairing and regenerating bone defects and injuries. Polysaccharides, due to their biocompatibility, biodegradability as well as bioactivity, have emerged as promising candidates for scaffolds or composite systems in BTE. Polymers combined with bioactive ceramics can support osteointegration. Calcium phosphate (CaP) ceramics can be a broad choice as an inorganic phase that stimulates the formation of new apatite layers. This review provides a comprehensive analysis of composite systems based on selected polysaccharides used in bone tissue engineering, highlighting their synthesis, properties and applications. Moreover, the applicability of the produced biocomposites has been analyzed, as well as new trends in modifying biomaterials and endowing them with new functionalizations. The effects of these composites on the mechanical properties, biocompatibility and osteoconductivity were critically analyzed. This article summarizes the latest manufacturing methods as well as new developments in polysaccharide-based biomaterials for bone and cartilage regeneration applications.
Citation: Materials
PubDate: 2024-08-27
DOI: 10.3390/ma17174220
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4221: Dimensional Accuracy of Novel Vinyl
Polysiloxane Compared with Polyether Impression Materials: An In Vitro
Study
Authors: Moritz Waldecker, Stefan Rues, Peter Rammelsberg, Wolfgang Bömicke
First page: 4221
Abstract: Transferring the intraoral situation accurately to the dental laboratory is crucial for fabricating precise restorations. This study aimed to compare the dimensional accuracy of a new hydrophilic quadrofunctional vinyl polysiloxane (VPS) and polyether (PE), in combination with different impression techniques (mono-phase single step or dual-phase single step). The reference model simulated a partially edentulous mandible. Stainless-steel precision balls were welded to specific teeth and were used to detect dimensional deviations. Fifteen impressions were made for each of the following four test groups: (1) VPS mono-phase, (2) PE mono-phase, (3) VPS dual-phase, and (4) PE dual-phase. Global accuracy was measured by deviations from the reference model, while local accuracy focused on the trueness and precision of abutment tooth surfaces. Statistical analysis was conducted using ANOVA (α = 0.05). All distances were underestimated, with the highest global inaccuracies for the cross-arch distance, ranging from −82 µm to −109 µm. The abutment tooth surfaces showed excellent local accuracy for all the materials and techniques, with crown surface trueness < 10 µm and precision < 12 µm. Inlay surfaces had higher inaccuracies (trueness < 15 µm, precision < 26 µm). Within the limitations of this study, all impression materials and techniques can be used to produce models with clinically acceptable accuracy.
Citation: Materials
PubDate: 2024-08-27
DOI: 10.3390/ma17174221
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4222: Prediction of Mechanical Properties of
Lattice Structures: An Application of Artificial Neural Networks
Algorithms
Authors: Jiaxuan Bai, Menglong Li, Jianghua Shen
First page: 4222
Abstract: The yield strength and Young’s modulus of lattice structures are essential mechanical parameters that influence the utilization of materials in the aerospace and medical fields. Currently, accurately determining the Young’s modulus and yield strength of lattice structures often requires conduction of a large number of experiments for prediction and validation purposes. To save time and effort to accurately predict the material yield strength and Young’s modulus, based on the existing experimental data, finite element analysis is employed to expand the dataset. An artificial neural network algorithm is then used to establish a relationship model between the topology of the lattice structure and Young’s modulus (the yield strength), which is analyzed and verified. The Gibson–Ashby model analysis indicates that different lattice structures can be classified into two main deformation forms. To obtain an artificial neural network model that can accurately predict different lattice structures and be deployed in the prediction of BCC-FCC lattice structures, the artificial network model is further optimized and validated. Concurrently, the topology of disparate lattice structures gives rise to a certain discrete form of their dominant deformation, which consequently affects the neural network prediction. In conclusion, the prediction of Young’s modulus and yield strength of lattice structures using artificial neural networks is a feasible approach that can contribute to the development of lattice structures in the aerospace and medical fields.
Citation: Materials
PubDate: 2024-08-27
DOI: 10.3390/ma17174222
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4223: Insight into Grain Refinement Mechanisms
of WC Cemented Carbide with Al0.5CoCrFeNiTi0.5 Binder
Authors: Fengming Qiang, Pengfei Zheng, Pan He, Wen Wang, Ying Zhang, Peng Han, Kuaishe Wang
First page: 4223
Abstract: High-entropy alloys (HEA) as a kind of new binder for cemented carbide have garnered significant attention. In this work, WC/(17~25 wt.%)Al0.5CoCrFeNiTi0.5 cemented carbides were prepared by hot pressing sintering (HPS), and the reactions between WC powder and Al0.5CoCrFeNiTi0.5 powder during hot pressing sintering were elucidated. It found that different from traditional Co binder, the Al0.5CoCrFeNiTi0.5 binder effectively inhibited WC grain growth. During HPS, the decomposed W and C atoms from WC diffused into the Al0.5CoCrFeNiTi0.5 binder, reacted with the elements in the binder, and then formed the M(Co, Fe, Ni)3W3C phase. The back-diffusion of W and C atoms to WC grains was restricted by the Al0.5CoCrFeNiTi0.5 alloy and inhibited them from re-precipitating onto the large undissolved WC grains. As a result, the average size of WC grains in the cemented carbides was less than 200 nm. This work bright new insight into the grain refinement mechanisms of WC cemented carbide with HEA binder and provide a guidance for designing performance-stable WC/HEA cemented carbide and promoting their application.
Citation: Materials
PubDate: 2024-08-27
DOI: 10.3390/ma17174223
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4224: Development of Thyme-Infused
Polydimethylsiloxane Composites for Enhanced Antibacterial Wound Dressings
Authors: Sara Sarraj, Małgorzata Szymiczek, Anna Mertas, Agata Soluch, Dariusz Jędrejek, Sebastian Jurczyk
First page: 4224
Abstract: Polydimethylsiloxane (PDMS) is widely used in biomedical applications due to its biocompatibility and flexibility but faces challenges due to its hydrophobicity and limited mechanical strength. This study explores the incorporation of thyme (Thymus vulgaris L.) into PDMS to enhance its properties for wound dressing applications. PDMS composites containing 2.5 wt.% and 5 wt.% of thyme were prepared and evaluated for physical, chemical, mechanical, and biological properties. Scanning electron microscopy, contact angle measurements, absorption tests, Fourier-transform infrared spectroscopy, differential scanning calorimetry, hardness, tensile testing, antibacterial activity, and cell viability assays were conducted. Thyme integration improved mechanical properties with increased absorption and preserved hydrophobicity. FTIR and DSC analyses indicated minimally altered crystallinity and chemical interactions. Hardness decreased with higher thyme content due to terpene-induced polymerization inhibition. Tensile testing showed reduced stress at break but increased elongation, suitable for wound dressings. Enhanced antibacterial activity was observed, with composites meeting bacteriostatic standards. Cell viability exceeded 70%, with optimal results at 2.5 wt.% thyme, attributed to cytokine-inducing compounds. Thyme-incorporated PDMS composites exhibit improved antibacterial and mechanical properties, demonstrating the potential for advanced wound dressings.
Citation: Materials
PubDate: 2024-08-27
DOI: 10.3390/ma17174224
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4225: Study on Crack Behavior of GH3230
Superalloy Fabricated via High-Throughput Additive Manufacturing
Authors: Xiaoqun Li, Yaqing Hou, Weidong Cai, Hongyao Yu, Xuandong Wang, Fafa Li, Yazhou He, Dupeng He, Hao Zhang
First page: 4225
Abstract: This study utilized Fe, Co, Ni elemental powders alongside GH3230 pre-alloyed powder as raw materials, employing high-throughput additive manufacturing based on laser powder bed fusion in situ to alloying technology to fabricate the bulk samples library for GH3230 superalloy efficiently. A quantitative identification algorithm for detecting crack and hole defects in additive manufacturing samples was developed. The primary focus was to analyze the composition variations in specimens at varying Fe, Co, and Ni elemental compositions and their impact on crack formation. Experimental results demonstrated that increased laser power improved element distribution uniformity but it proved to be not significantly effective in reducing crack defects. Moreover, augmented Fe and Co alloying content could not eliminate these defects. However, elevated Ni content led to a decrease in the alloy’s solidification cracking index and carbide reduction in solidification products. Notably, a significant reduction in cracks was observed when the Ni content of the alloy reached 63 wt.%, and these defects were nearly eliminated at 67 wt.% Ni content.
Citation: Materials
PubDate: 2024-08-27
DOI: 10.3390/ma17174225
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4226: Optimization Method of Floating Fixture
Layout for Distortion Control of Low-Stiffness Thin-Walled Beams
Authors: Junping Feng, Jiawei Wang, Zhuang Mu, Yifei Gu, Zongyang Du, Wenbo He, Kean Aw, Yinfei Yang
First page: 4226
Abstract: The aim is to reduce the elastic deformation of the web and side walls of low-stiffness thin-walled beams when the floating fixture method is used. This paper takes the number and position of fixture points as the optimization variables, establishes a calculation model of elastic deformation, and constructs the objective function of maximum total elastic deformation. An optimized solution utilizing the augmented multiplier method is employed, which forms the basis for the fixture layout optimization method to reduce the elastic deformation of low-stiffness thin-walled beams. A theoretical calculation, simulation analysis, and the fixture layout optimization of total maximum elastic deformation were completed using an aluminum alloy low-stiffness thin-walled beam as an example. The results show that based on the optimized layout, the average relative error between the calculated value and the simulated value of total maximum elastic deformation is 17.43%, and the simulated value of maximum elastic deformation is reduced by 48.49% after optimizing the fixture layout. The measured value is reduced by 0.02 mm on average, and deformation is reduced by 74.07%, which verifies the effectiveness of the floating fixture layout optimization control of machining elastic deformation proposed in this paper.
Citation: Materials
PubDate: 2024-08-27
DOI: 10.3390/ma17174226
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4227: Production of Biopolymeric Microparticles
to Improve Cannabigerol Bioavailability
Authors: Lucia Baldino, Sonia Sarnelli, Mariarosa Scognamiglio, Ernesto Reverchon
First page: 4227
Abstract: Cannabigerol’s (CBG) therapeutic effects are limited by its poor water solubility and low dissolution rate. To improve these properties, supercritical CO2-assisted atomization (SAA) was applied to produce coprecipitates, i.e., CBG nanoparticles coprecipitated in polyvinylpyrrolidone (PVP) microparticles. The experiments were performed by varying the CBG/PVP mass ratio (R) and the overall concentration of solutes CBG+PVP to study the influence of these parameters on particle morphology, particle size, and size distribution. Periodic dynamic light scattering (DLS) analysis was performed at regular time intervals to measure the size of CBG nanoparticles in PVP microparticles. It showed that CBG nanoparticles down to 105 nm were successfully produced through SAA. Dissolution tests were used to verify that a reduction of CBG particle size significantly increased its dissolution rate. In the liquid medium adopted, untreated CBG powder was released in 210 min, whereas CBG nanoparticles of 105 nm were completely dissolved in only 15 min.
Citation: Materials
PubDate: 2024-08-27
DOI: 10.3390/ma17174227
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4228: The Specificity of Determining the Latent
Heat of Solidification of Cast Hypoeutectic AlSiCu Alloys Using the DSC
Method
Authors: Mile B. Đjurdjević, Vladimir Jovanović, Mirko Komatina, Srecko Stopic
First page: 4228
Abstract: Latent heat is commonly measured using Differential Thermal Analysis (DTA) or Differential Scanning Calorimetry (DSC) or calculated using software packages (Thermo-Calc). In this study, the DSC method was used to comprehensively evaluate the accuracy of calculated latent heat for a specific range of cast AlSiCu alloys, considering their solidification under different cooling conditions. The tests involved varying concentrations of two crucial alloying elements: wSi (5, 7, and 9%) and wCu (1, 2, and 4%). All selected alloys were analyzed under three distinct cooling/heating rates: 6, 10, and 50 °C/min. The Thermo-Calc method was used in this work to calculate the latent heats of the investigated alloys. The results obtained show good agreement between the measured and calculated values. The increase in silicon content in the investigated alloys from 4.85% to 9.85% resulted in the increase in latent heat from 407.6 kJ/kg to 467.5 kJ/kg. Higher cooling rates, such as 50 °C/min, resulted in a reduced latent heat release compared to slower rates such as 10 °C/min and 6 °C/min.
Citation: Materials
PubDate: 2024-08-27
DOI: 10.3390/ma17174228
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4229: The Effect of Calcium and Iron (III)
Oxides on Lead Spent Plates: Spectroscopic, Voltametric, and EIS
Investigations
Authors: Delia N. Piscoiu, Simona Rada, Sergiu Macavei, Adriana Popa, Claudia A. Crisan, Horatiu Vermesan, Eugen Culea
First page: 4229
Abstract: In this study, xCaO‧5Fe2O3‧(95−x)Pb glasses and vitroceramics containing various concentrations of calcium ions (from 0 to 50 mol% CaO) were prepared using the spent anodic plate of a car battery. X-ray diffraction analysis revealed changes in the network structure as a function of CaO content. The intensities of the IR bands due to the sulfate and sulfite units were lowered, indicating a decrease in the sulfurization degree within the lead network. In the UV–vis spectra, the presence of electronic transitions of the Fe3+, Pb2+, and Fe2+ ions were identified. The EPR spectra were characterized by resonance signals centered at about g ~ 2 and 4.3, corresponding to the trivalent iron ions. For the samples with 5 ≤ x ≤ 12, the signals decreased abruptly, suggesting a Fe3+→Fe2+ interconversion and the formation of the Fe3O4 crystalline phase. A considerable increase in the intensity of the signal centered around g ~ 2 was observed as the CaO concentration increased to 30% in the host matrix. Our results confirm that the higher CaO levels of 3 mol% are responsible for the increase in the radius of curvature of the semicircle arcs in the EIS plots and the decrease in their conductivity.
Citation: Materials
PubDate: 2024-08-27
DOI: 10.3390/ma17174229
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4230: Determination of Fracture Mechanic
Parameters of Concretes Based on Cement Matrix Enhanced by Fly Ash and
Nano-Silica
Authors: Grzegorz Ludwik Golewski
First page: 4230
Abstract: This study presents test results and deep discussion regarding measurements of the fracture toughness of new concrete composites based on ternary blended cements (TCs). A composition of the most commonly used mineral additive (i.e., fly ash (FA)) in combination with nano-silica (NS) has been proposed as a partial replacement of the ordinary Portland cement (OPC) binder. The novelty of this article is related to the fact that ordinary concretes with FA + NS additives are most often used in construction practice, and there is a decided lack of fracture toughness test results concerning these materials. Therefore, in order to fill this gap in the literature, an extensive evaluation of the fracture mechanic parameters of TC was carried out. Four series of concretes were created, one of which was the reference concrete (REF), and the remaining three were TCs. The effect of a constant content of 5% NS and various FA contents, such as 0, 15%, and 25% wt., as a partial replacement of cement was studied. The parameters of the linear and nonlinear fracture mechanics were analyzed in this study (i.e., the critical stress intensity factor (KIcS), critical crack tip opening displacement (CTODc), and critical unit work of failure (JIc)). In addition, the main mechanical parameters (i.e., the compressive strength (fcm) and splitting tensile strength (fctm)) were evaluated. Based on the studies, it was found that the addition of 5% NS without FA increased the strength and fracture parameters of the concrete by approximately 20%. On the other hand, supplementing the composition of the binder with 5% NS in combination with the 15% FA additive caused an increase in all mechanical parameters by approximately another 20%. However, an increase in the FA content in the concrete mix of another 10% caused a smaller increase in all analyzed factors (i.e., by approximately 10%) compared with a composite with the addition of the NS modifier only. In addition, from an ecological point of view, by utilizing fine waste FA particles combined with extremely fine particles of NS to produce ordinary concretes, the demand for OPC can be reduced, thereby lowering CO2 emissions. Hence, the findings of this research hold practical importance for the future application of such materials in the development of green concretes.
Citation: Materials
PubDate: 2024-08-27
DOI: 10.3390/ma17174230
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4231: Controllable Preparation of Fused Silica
Micro Lens Array through Femtosecond Laser Penetration-Induced
Modification Assisted Wet Etching
Authors: Kaijie Cheng, Ji Wang, Guolong Wang, Kun Yang, Wenwu Zhang
First page: 4231
Abstract: As an integrable micro-optical device, micro lens arrays (MLAs) have significant applications in modern optical imaging, new energy technology, and advanced displays. In order to reduce the impact of laser modification on wet etching, we propose a technique of femtosecond laser penetration-induced modification-assisted wet etching (FLIPM-WE), which avoids the influence of previous modification layers on subsequent laser pulses and effectively improves the controllability of lens array preparation. We conducted a detailed study on the effects of the laser single pulse energy, pulse number, and hydrofluoric acid etching duration on the morphology of micro lenses and obtained the optimal process parameters. Ultimately, two types of fused silica micro lens arrays with different focal lengths but the same numerical aperture (NA = 0.458) were fabricated using the FLPIM-WE technology. Both arrays exhibited excellent geometric consistency and surface quality (Ra~30 nm). Moreover, they achieved clear imaging at various magnifications with an adjustment range of 1.3×~3.0×. This provides potential technical support for special micro-optical systems.
Citation: Materials
PubDate: 2024-08-27
DOI: 10.3390/ma17174231
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4232: Adsorption of Selected Herbicides on
Activated Carbon from Single- and Multi-Component Systems—Error
Analysis in Isotherm Measurements
Authors: Magdalena Blachnio, Malgorzata Zienkiewicz-Strzalka, Anna Derylo-Marczewska
First page: 4232
Abstract: The aim of this study is to examine the influence of various factors on the precision and repeatability of the experimental determination of herbicide adsorption isotherms. Studies were conducted for the activated carbon RIB as an adsorbent and three herbicides as adsorbates: 2,4-dichlorophenoxyacetic acid (2,4-D), 4-chlorophenoxyacetic acid (4-CPA), and 3-chlorophenoxypropionic acid (3-CPP). The herbicide adsorption process was carried out in single-component and multi-component modes (the herbicide was adsorbed in the presence of an accompanying substance, i.e., 4-nitroaniline (4-NA)). Due to the significant contribution of the competition phenomenon in the adsorption process, which is important, e.g., in multi-component environmental systems, a qualitative and quantitative analysis of herbicide adsorption in the presence of a competing substance was presented. This work presents, among other things, the influence of adsorbent heterogeneity (grain size) on measurement uncertainties. The spread of standard deviations for solutions requiring dilution during spectrophotometric measurements was discussed, indicating that dilutions contribute to increasing measurement uncertainties. The heterogeneity parameters of the Freundlich equation for the studied adsorption systems were analyzed; the 2,4-D/RIB system was indicated as the most energetically heterogeneous. Differentiation of the experimental conditions (pH, temperature) allowed us to assess their impact on the efficiency and mechanism of adsorption. A high repeatability of experimental isotherms was obtained for the multi-component system. The accuracy of quantitative determination of equilibrium concentrations for the tested two-component systems was assessed based on the measured UV-Vis spectra, and the adsorption of herbicides from single- and multi-component systems was compared.
Citation: Materials
PubDate: 2024-08-27
DOI: 10.3390/ma17174232
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4233: Deep Indentation Tests of Soft Materials
Using Mobile and Stationary Devices
Authors: Joanna Nowak, Mariusz K. Kaczmarek
First page: 4233
Abstract: Measurements of the properties of soft materials are important from the point of view of medical diagnostics of soft tissues as well as testing the quality of food products and many technical materials. One of the frequently used techniques for testing such materials, attractive due to its non-invasive nature, is the indentation technique, which does not puncture the material. The difficulty of testing soft materials, which affects the objectivity of the results, is related to the problems of stable positioning of the studied material in relation to the indentation apparatus, especially with a device held by the operator. This work concerns the comparison of test results using an indentation apparatus mounted on mobile and stationary handles. The tested materials are cylindrical samples of polyurethane foams with three different stiffnesses and the same samples with a 0.5 or 1 mm thick silicone layer. The study presented uses an apparatus with a flat cylindrical indenter, with a surface area of 1 cm2, pressed to a depth of 10 mm (so-called deep tests). Based on the recorded force changes over time, five descriptors of the indentation test were determined and compared for both types of handles. The tests performed showed that the elastic properties of foam materials alone and with a silicone layer can be effectively characterized by the maximum forces during recessing and retraction and the slopes of the recessing and retraction curves. In the case of two-layer materials, these descriptors reflect both the characteristics of the foams and the silicone layer. The results show that the above property of the deep indentation method distinguishes it from the shallow indentation method. The repeatability of the tests performed in the mobile and stationary holders were determined to be comparable.
Citation: Materials
PubDate: 2024-08-27
DOI: 10.3390/ma17174233
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4234: Effect of Bias Arc on Microstructure and
Corrosion Resistance of Q235/304 Dissimilar-Steel-Welded Joints
Authors: Lin Li, Rongcai Ma, Cheng Yang, Tie Liu, Guorui Sun, Wenlong Li, Chuanchuan Jia, Chao Chen, Fengya Hu
First page: 4234
Abstract: To fully exploit the advantages of steel, the welding connection of dissimilar steels has been developed. In this work, the metallographic microstructures, elemental distributions, and electrochemical corrosion properties of the Q235 and 304 welds under different bias arcs were investigated. The arc bias caused the Q235-side heat-affected zone to widen, the microstructure consisted of ferrite and pearlite, and the ratio varied with decreasing distance from the fusion line. Elemental scans show that Cr and Ni concentration gradients exist near the fusion line. The 304-stainless-steel-side heat-affected zone was mainly composed of austenite grains, and the fusion zone was narrower but prone to cracking. Electrochemical tests revealed that 304 stainless steel had the best corrosion resistance, while Q235 had the worst corrosion resistance, and that the welded joints with an arc bias toward the 304 side had the best corrosion resistance. The samples’ the passivation film which formed via electrochemical polarization had limited stability, but the over-passivation potential could be used as a reference for corrosion resistance. Overall, the arc bias and weld material properties significantly affected the microstructure and corrosion resistance of the joints.
Citation: Materials
PubDate: 2024-08-27
DOI: 10.3390/ma17174234
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4235: Research Progress on the Microstructure
Evolution Mechanisms of Al-Mg Alloys by Severe Plastic Deformation
Authors: Chang-Rong Song, Si-Yu Zhang, Lin Liu, Hong-Yu Yang, Jie Kang, Jia Meng, Chang-Jie Luo, Cheng-Gang Wang, Kuang Cao, Jian Qiao, Shi-Li Shu, Ming Zhu, Feng Qiu, Qi-Chuan Jiang
First page: 4235
Abstract: Al-Mg alloys are widely used as important engineering structural materials in aerospace engineering, transportation systems, and structural constructions due to their low density, high specific strength, corrosion resistance, welding capability, fatigue strength, and cost-effectiveness. However, the conventional Al-Mg alloys can no longer fully satisfy the demands of practical production due to difficulties caused by many defects. The high strength of Al-Mg alloys as non-heat treatment precipitation-strengthened alloys is achieved primarily by solid solution strengthening along with work hardening rather than precipitation strengthening. Therefore, severe plastic deformation (SPD) techniques can be often used to produce ultrafine-grained structures to fabricate ultra-high strength aluminum alloys. However, this approach often achieves the strengthening of material at the cost of reduced ductility. This paper comprehensively summarizes the various approaches of ultrafine/nanocrystalline materials for enhancing their plasticity, elaborates on the creation of a bimodal microstructure within the alloy, and discusses the formation of a nanotwin microstructure within the alloy and the incorporation of dispersed nanoparticles. The mechanisms underlying both the strengthening and toughening during large plastic deformation in aluminum alloys are summarized, and the future research direction of high-performance ultrafine crystalline and nanocrystalline Al-Mg aluminum alloys is prospected.
Citation: Materials
PubDate: 2024-08-27
DOI: 10.3390/ma17174235
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4236: Hot Workability and Microstructure
Evolution of Homogenized 2050 Al-Cu-Li Alloy during Hot Deformation
Authors: Zhiyong Sheng, Yuanchun Huang, Yongxing Zhao, Rong Fu, Xucheng Wang, Xi Fan, Fan Wu
First page: 4236
Abstract: For this article, hot compression tests were carried out on homogenized 2050 Al-Cu-Li alloys under different deformation temperatures and strain rates, and an Arrhenius-type constitutive model with strain compensation was established to accurately describe the alloy flow behavior. Furthermore, thermal processing maps were created and the deformation mechanisms in different working regions were revealed by microstructural characterization. The results showed that most of the deformed grains orientated toward <101>//CD (CD: compression direction) during the hot compression process, and, together with some dynamic recovery (DRV), dynamic recrystallization (DRX) occurred. The appearance of large-scale DRX grains at low temperatures rather than in high-temperature conditions is related to the particle-stimulated nucleation mechanism, due to the dynamic precipitation that occurs during the deformation process. The hot-working diagrams with a true strain of 0.8 indicated that the high strain-rate regions C (300 °C–400 °C, 0.1–1 s−1) and D (440 °C–500 °C, 0.1–1 s−1) are unfavorable for the processing of 2050 Al-Li alloys, owing to the flow instability caused by local deformation banding, microcracks, and micro-voids. The optimum processing region was considered to be 430 °C–500 °C and 0.1 s−1–0.001 s−1, with a dissipation efficiency of more than 30%, dominated by DRV and DRX; the DRX mechanisms are DDRX and CDRX.
Citation: Materials
PubDate: 2024-08-27
DOI: 10.3390/ma17174236
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4237: Hydrogen Embrittlement Detection
Technology Using Nondestructive Testing for Realizing a Hydrogen Society
Authors: Yamato Abiru, Hiroshi Nishiguchi, Masato Maekawa, Takara Nagata, Toshiya Itaya, Michie Koga, Toshiomi Nishi
First page: 4237
Abstract: Crack detection in high-pressure hydrogen gas components, such as pipes, is crucial for ensuring the safety and reliability of hydrogen infrastructure. This study conducts the nondestructive testing of crack propagation in steel piping under cyclic compressive loads in the presence of hydrogen in the material. The specimens were hydrogen-precharged through immersion in a 20 mass% ammonium thiocyanate solution at 40 °C for 72 h. The crack growth rate in hydrogen-precharged specimens was approximately 10 times faster than that in uncharged specimens, with cracks propagating from the inner to outer surfaces of the pipe. The fracture surface morphology differed significantly, with flat surfaces in hydrogen-precharged materials and convex or concave surfaces in uncharged materials. Eddy current and hammering tests revealed differences in the presence of large cracks between the two materials. By contrast, hammering tests revealed differences in the presence of a half size crack between the two materials. These findings highlight the effect of hydrogen precharging on crack propagation in steel piping and underscore the importance of early detection methods.
Citation: Materials
PubDate: 2024-08-27
DOI: 10.3390/ma17174237
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4238: Material Removal Mechanisms of
Polycrystalline Silicon Carbide Ceramic Cut by a Diamond Wire Saw
Authors: Huyi Yang, Ming Fu, Xin Zhang, Kailin Zhu, Lei Cao, Chunfeng Hu
First page: 4238
Abstract: Polycrystalline silicon carbide (SiC) is a highly valuable material with crucial applications across various industries. Despite its benefits, processing this brittle material efficiently and with high quality presents significant challenges. A thorough understanding of the mechanisms involved in processing and removing SiC is essential for optimizing its production. In this study, we investigated the sawing characteristics and material removal mechanisms of polycrystalline silicon carbide (SiC) ceramic using a diamond wire saw. Experiments were conducted with high wire speeds of 30 m/s and a maximum feed rate of 2.0 mm/min. The coarseness value (Ra) increased slightly with the feed rate. Changes in the diamond wire during the grinding process and their effects on the grinding surface were analyzed using scanning electron microscopy (SEM), laser confocal microscopy, and focused ion beam (FIB)-transmission electron microscopy (TEM). The findings provide insights into the grinding mechanisms. The presence of ductile grinding zones and brittle fracture areas on the ground surface reveals that external forces induce dislocation and amorphization within the grain structure, which are key factors in material removal during grinding.
Citation: Materials
PubDate: 2024-08-27
DOI: 10.3390/ma17174238
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4239: Influence of the Composition of
Provisional Luting Materials on the Bond Strength of Temporary
Single-Tooth Crowns on Titanium Abutments
Authors: Christina Maubach, Heike Rudolph, Arndt Happe, Ralph G. Luthardt, Katharina Kuhn, Sarah M. Blender
First page: 4239
Abstract: In addition to zinc oxide-based cements, resin-based materials are also available for temporary cementation. The aim of this in vitro study was to determine the influence of the different material compositions on temporary bonds. In nine test series (n = 30), temporary bis-acrylate single-tooth crowns were bonded onto prefabricated titanium abutments with nine different temporary luting materials. After simulating an initial (24 h, distilled water, 37 °C), a short-term (7 days, distilled water, 37 °C) and a long-term provisional restoration period (12h, distilled water, 37 °C; thermocycling: 5000 cycles) in subgroups (n = 10), the bond strength was examined using a combined tensile–shear test. Statistical analysis was performed by univariate analysis of variance or a non-parametric Kruskal–Wallis test, followed by post hoc tests. Of the three resin-based materials, two showed significantly higher bond strength values compared to all other materials (p < 0.001), regardless of the storage procedure. The resin-based materials were followed by eugenol-free and eugenol-containing zinc oxide materials. Significant intragroup differences were observed between the composite-based materials after all storage periods. This was only observed for some of the zinc oxide-based materials. The results show that under in vitro conditions, not only the composition of the temporary luting materials but also the different storage conditions have a significant influence on temporary bonds.
Citation: Materials
PubDate: 2024-08-27
DOI: 10.3390/ma17174239
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4240: The Abrasive Effect of Moon and Mars
Regolith Simulants on Stainless Steel Rotating Shaft and
Polytetrafluoroethylene Sealing Material Pairs
Authors: Gábor Kalácska, György Barkó, Hailemariam Shegawu, Ádám Kalácska, László Zsidai, Róbert Keresztes, Zoltán Károly
First page: 4240
Abstract: For space missions to either the Moon or Mars, protecting mechanical moving parts from the abrasive effects of prevailing surface dust is crucial. This paper compares the abrasive effects of two lunar and two Martian simulant regoliths using special pin-on-disc tests on a stainless steel/polytetrafluoroethylene (PTFE) sealing material pair. Due to the regolith particles entering the contact zone, a three-body abrasion mechanism took place. We found that friction coefficients stabilised between 0.2 and 0.4 for all simulants. Wear curves, surface roughness measurements, and microscopic images all suggest a significantly lower abrasion effect of the Martian regoliths than that of the lunar ones. It applies not only to steel surfaces but also to the PTFE pins. The dominant abrasive micro-mechanism of the disc surface is micro-ploughing in the case of all tests, while the transformation of the counterface is mixed. The surface of pin material is plastically transformed through micro-ploughing, while the material is removed through micro-cutting due to the slide over hard soil particles.
Citation: Materials
PubDate: 2024-08-27
DOI: 10.3390/ma17174240
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4241: Generation of Customized Bone Implants
from CT Scans Using FEA and AM
Authors: Claude Wolf, Deborah Juchem, Anna Koster, Wilfrid Pilloy
First page: 4241
Abstract: Additive manufacturing (AM) allows the creation of customized designs for various medical devices, such as implants, casts, and splints. Amongst other AM technologies, fused filament fabrication (FFF) facilitates the production of intricate geometries that are often unattainable through conventional methods like subtractive manufacturing. This study aimed to develop a methodology for substituting a pathological talus bone with a personalized one created using additive manufacturing. The process involved generating a numerical parametric solid model of the specific anatomical region using computed tomography (CT) scans of the corresponding healthy organ from the patient. The healthy talus served as a mirrored template to replace the defective one. Structural simulation of the model through finite element analysis (FEA) helped compare and select different materials to identify the most suitable one for the replacement bone. The implant was then produced using FFF technology. The developed procedure yielded commendable results. The models maintained high geometric accuracy, while significantly reducing the computational time. PEEK emerged as the optimal material for bone replacement among the considered options and several specimens of talus were successfully printed.
Citation: Materials
PubDate: 2024-08-27
DOI: 10.3390/ma17174241
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4242: Influence of Solder Mask on
Electrochemical Migration on Printed Circuit Boards
Authors: Markéta Klimtová, Petr Veselý, Iva Králová, Karel Dušek
First page: 4242
Abstract: Electrochemical migration (ECM) on the surface of printed circuit boards (PCBs) continues to pose a significant reliability risk in electronics. Nevertheless, the existing literature lacks studies that address the solder mask and solder pad design aspects in the context of ECM. Therefore, the objective of this study was to assess the impact of solder mask type with varying roughness and solder pad design on the susceptibility to ECM using a water drop test and thermal humidity bias test. Hot air solder leveling-coated PCBs were tested. Furthermore, the ECM tests were conducted on PCBs with applied no-clean solder paste to evaluate the influence of flux residues on the resulting ECM behavior. The results indicated that the higher roughness of the solder mask significantly contributes to ECM inhibition through the creation of a mechanical barrier for the dendrites. Furthermore, lower ECM susceptibility was also observed for copper-defined pads, where a similar effect is presumed. However, the influence of the no-clean flux residues can prevail over the effects of the solder mask. Therefore, the use of a rough solder mask and a copper-defined pad design is recommended if the PCB is to be washed from flux residues after the soldering process.
Citation: Materials
PubDate: 2024-08-27
DOI: 10.3390/ma17174242
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4243: Process Parameters Optimization and
Numerical Simulation of AlCoCrFeNi High-Entropy Alloy Coating via Laser
Cladding
Authors: Bin Chen, Yang Zhao, Hui Yang, Jingjing Zhao
First page: 4243
Abstract: The use of laser cladding technology to prepare coatings of AlCoCrFeNi high-entropy alloy holds enormous potential for application. However, the cladding quality will have a considerable effect on the properties of the coatings. In this study, considering the complex coupling relationship between cladding quality and the process parameters, an orthogonal experimental design was employed, with laser power, scanning speed, and powder feed rate as correlation factor variables, and microhardness, dilution rate, and aspect ratio as characteristic variables. The experimental data underwent gray correlation analysis to determine the effect of various process parameters on the quality of cladding. Then, the NSGA-II algorithm was used to establish a multi-objective optimization model of process parameters. Finally, the ANSYS Workbench simulation model was employed to conduct numerical simulations on a group of optimized process parameters and analyze the change rule of the temperature field. The results demonstrate that the laser cladding coating of AlCoCrFeNi high-entropy alloy with the single pass is of high quality within the determined orthogonal experimental parameters. The powder feed rate exerts the most significant influence on microhardness, while laser power has the greatest impact on dilution rate, and scanning speed predominantly affects aspect ratio. The designed third-order polynomial nonlinear regression model exhibits a high fitting accuracy, and the NSGA-II algorithm can be used for multi-objective optimization to obtain the Pareto front solution set. The numerical simulation results demonstrate that the temperature field of AlCoCrFeNi high-entropy alloy laser cladding exhibits a “comet tail” phenomenon, where the highest temperature of the molten pool is close to 3000 °C. The temperature variations in the molten pool align with the features of laser cladding technology. This study lays the groundwork for the widespread application of laser cladding AlCoCrFeNi high-entropy alloy in surface engineering, additive manufacturing, and remanufacturing. Researchers and engineering practitioners can utilize the findings from this research to judiciously manage processing parameters based on the results of gray correlation analysis. Furthermore, the outcomes of multi-objective optimization can assist in the selection of appropriate process parameters aligned with specific application requirements. Additionally, the methodological approach adopted in this study offers valuable insights applicable to the exploration of various materials and diverse additive manufacturing techniques.
Citation: Materials
PubDate: 2024-08-27
DOI: 10.3390/ma17174243
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4244: Natural Fiber-Reinforced Composite
Incorporated with Anhydride-Cured Epoxidized Linseed-Oil Resin and
Atmospheric Pressure Plasma-Treated Flax Fibers
Authors: Sofya Savicheva, Bastian E. Rapp, Nico Teuscher
First page: 4244
Abstract: Fiber-reinforced composites (FRCs) represent a promising class of engineering materials due to their mechanical performance. However, the vast majority of FRCs are currently manufactured using carbon and glass fibers, which raises concerns because of the difficulties in recycling and the reliance on finite fossil resources. On the other hand, the use of natural fibers is still hampered due to the problems such as, e.g., differences in polarity between the reinforcement and the polymer matrix components, leading to a significant decrease in composite durability. In this work, we present a natural fiber-reinforced composite (NFRC), incorporating plasma pre-treated flax fibers as the reinforcing element, thermoplastic polylactic acid (PLA) as a matrix, and a key point of the current study—a thermoset coating based on epoxidized linseed oil for adhesion improvement. Using atmospheric plasma-jet treatment allows for increasing the fiber’s surface energy from 20 to 40 mN/m. Furthermore, a thermoset coating layer based on epoxidized linseed oil, in conjunction with dodecyl succinic anhydride (DDSA) as a curing agent and 2,4,6-tris(dimethyl amino methyl) phenol (DMP-30) as a catalyst, has been developed. This coated layer exhibits a decomposition temperature of 350 °C, and there is a substantial increase in the dispersive surface-energy part of the coated flax fibers from 8 to 30 mN/m. The obtained natural fiber-reinforced composite (NFRC) was prepared by belt-pressing with a PLA film, and its mechanical properties were evaluated by tensile testing. The results showed an elastic modulus up to 18.3 GPa, which is relevant in terms of mechanical properties and opens up a new pathway to use natural-based fiber-reinforced bio-based materials as a convenient approach to greener FRCs.
Citation: Materials
PubDate: 2024-08-28
DOI: 10.3390/ma17174244
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4245: Study on Grouting Performance Optimization
of Polymer Composite Materials Applied to Water Plugging and Reinforcement
in Mines
Authors: Xuanning Zhang, Ende Wang, Sishun Ma, Deqing Zhang
First page: 4245
Abstract: With the increasing drilling depth of mines, the cross-complexity of fissures in the rock body, and the frequent occurrence of sudden water surges, polymer slurry, with its advantages of good permeability and strong water plugging, is increasingly used in mine grouting projects. Additional research is needed in order to further improve the grouting performance of polymer slurry, ensure the safety of mining operations, and reduce the grouting cost. In this paper, a polymer composite grouting material was prepared with diphenyl methyl diisocyanate, polyether polyol, and fly ash, as the main raw materials, with coupling agent and catalyst as auxiliary reagents. The performance of the composite grouting material in terms of mechanical properties, thermal stability, hydrophobicity, and bonding was explored. This study’s findings indicated that incorporating fly ash led to notable enhancements in the thermal stability and water resistance of the polymer slurry. Furthermore, the introduction of fly ash notably raised the starting degradation temperature of the polymer, boosted the water contact angle of the composite material, and reduced the density and reaction temperature of the composite material. In addition, the catalyst and coupling agent as auxiliary reagents affected the polymers in terms of mechanical properties; in this paper, dibutyltin dilaurate was used as the catalyst, and organosilanes were used as the coupling agent. The catalyst successfully sped up the polymer’s gel time, however, an excessive quantity of catalyst compromised the polymer’s mechanical characteristics. The addition of organosilanes has a positive effect on the dynamic mechanical properties of the composites, fracture toughness, compression, bending, and bond strength. The research can offer a theoretical direction for creating polymer mixtures in mine grouting projects.
Citation: Materials
PubDate: 2024-08-28
DOI: 10.3390/ma17174245
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4246: Research on the Mechanical Response and
Constitutive Model of 18Ni300 Manufactured by SLM with Different Build
Directions
Authors: Zhenchao Liang, Qing Zhang, Wenbin Li, Weihang Li
First page: 4246
Abstract: Metals manufactured by selective laser melting (SLM) with different directions exhibit different mechanical properties. This study conducted dynamic and static mechanical tests using a universal testing machine and split-Hopkinson bar (SHPB). The mechanical properties of 18Ni300 with 0° and 90° build directions manufactured by SLM were compared, and the micro-structure properties of the two build directions were analysed by metallographic tests. The Johnson–Cook (J-C) constitutive model was fitted according to the experimental results, and the obtained constitutive parameters were verified by numerical simulations. The results revealed that the constitutive model could predict the mechanical properties of 18Ni300 in a dynamic state. The build direction had little influence on the mechanical properties in a static state, but there was a significant difference in the dynamic state. The difference in the dynamic compressive yield strength of the 18Ni300 material manufactured by SLM with two build directions was 9.8%. The SLM process can be improved to produce 18Ni300 with uniform mechanical properties by studying the reasons for this difference.
Citation: Materials
PubDate: 2024-08-28
DOI: 10.3390/ma17174246
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4247: Nanocrystalline Cellulose to Reduce
Superplasticizer Demand in 3D Printing of Cementitious Materials
Authors: Rocío Jarabo, Elena Fuente, José Luis García Calvo, Pedro Carballosa, Carlos Negro
First page: 4247
Abstract: One challenge for 3D printing is that the mortar must flow easily through the printer nozzle, and after printing, it must develop compressive strength fast and high enough to support the layers on it. This requires an exact and difficult control of the superplasticizer (SP) dosing. Nanocrystalline cellulose (CNC) has gained significant interest as a rheological modifier of mortar by interacting with the various cement components. This research studied the potential of nanocrystalline cellulose (CNC) as a mortar aid for 3D printing and its interactions with SPs. Interactions of a CNC and SP with cement suspensions were investigated by means of monitoring the effect on cement dispersion (by monitoring the particle chord length distributions in real time) and their impact on mortar mechanical properties. Although cement dispersion was increased by both CNC and SP, only CNC prevented cement agglomeration when shearing was reduced. Furthermore, combining SP and CNC led to faster development of compressive strength and increased compressive strength up to 30% compared to mortar that had undergone a one-day curing process.
Citation: Materials
PubDate: 2024-08-28
DOI: 10.3390/ma17174247
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4248: Development of Robust PEBAX-Based
Angiographic Catheter: Design and In Vitro Study
Authors: Hafsa Inam, Murtaza Najabat Ali, Ibraheem Raza Jameel, Dil Awaiz, Zunaira Qureshi
First page: 4248
Abstract: Background: Keeping in mind the unceasingly escalating prevalence of coronary disease worldwide, the mortality rate is also expected to rise with a staggering increase in healthcare costs. Angiography is the gold standard for diagnosing these blockages that trigger these diseases. Amides and urethanes are the common catheter construction material used for angiography. However, the experimental evidence verifying the use of PEBAX® and comparing its performance with that of commercially available catheters for angiography is not published despite it being well recognized for its excellent flexural modulus, mechanical properties, and biocompatibility and its potential to reduce the incidence of vascular spasm during intravascular diagnostic and interventional procedures. Therefore, the aim of this study was to develop a PEBAX®-based angiographic catheter and evaluate its performance in comparison with three commercially available nylon- and polyurethane-based angiographic catheters. Methodology: A PEBAX®-based angiographic catheter was developed for this purpose. This study analyzes and reports the performance and behavior of PEBAX®-, nylon-, and polyurethane-based catheters. The catheter’s performance and arterial forces’ endurance nature were mapped out by evaluating pushability (advancement force) and selective bench tests outlined in the applicable regulatory standard. Conclusions: The PEBAX®-based catheter exhibited the least bond-flexural rigidity (180.4 g), which was approximately one-third of that shown by all six French catheters and which exhibited the least advancement force (510.4 g), which was approximately 50% less than that of the nylon- and polyurethane-based catheters when traversing through the mock arterial system. Bench testing was carried out as per the applicable regulatory standard; the differences obtained between individual catheters were discussed in detail. Based on this extensive in vitro assessment, it was concluded that the PEBAX®-based catheters outperformed the nylon- and polyurethane-based catheters, exhibiting an exceptionally minimal advancement force of 510.4 g. This leads to the inference that this catheter can inject more radiopaque material (because of the enhanced flow rate) to the coronary arteries and can play a significant role in minimizing vascular spasms during a diagnostic procedure.
Citation: Materials
PubDate: 2024-08-28
DOI: 10.3390/ma17174248
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4249: Fabrication of Co-Based Cladding Layer by
Microbeam Plasma and Its Corrosion Mechanism to Molten Salt
Authors: Kaiqi Sun, Yufeng Zhang, Yingfan Wang, Fuxing Ye
First page: 4249
Abstract: Corrosion of the molten salts Na2SO4 and NaCl has become one of the major factors in the failure of steel components in boilers and engines. In this study, CoNiCrAlY cobalt-based cladding layers with different NiCr-Cr3C2 ratios were prepared by microbeam plasma cladding technology. The influence of the NiCr-Cr3C2 content on the microstructure, mechanical properties, and molten salt corrosion resistance of CoNiCrAlY was investigated. The CoNiCrAlY with a 25 wt.% NiCr-Cr3C2 (NC25) cladding layer possessed the highest microhardness (348.2 HV0.3) and the smallest coefficient of friction (0.4751), exhibiting great overall mechanical properties. The generation of protective oxides Cr2O3, Al2O3, and spinel phase (Ni,Co)Cr2O4 is promoted by the addition of 25 wt.% NiCr-Cr3C2, which significantly reduces the corrosion of the cladding layer, and this effect is much more obvious at 950 °C than that at 750 °C. Furthermore, its corrosion mechanism was clarified. From the findings emerge a viable solution for the design and development of new high-temperature corrosion-resistant coatings.
Citation: Materials
PubDate: 2024-08-28
DOI: 10.3390/ma17174249
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4250: Enhancing of Surface Quality of FDM
Moulded Materials through Hybrid Techniques
Authors: Monika Jabłońska, Olga Łastowska
First page: 4250
Abstract: With the rapid advancement of 3D-printing technology, additive manufacturing using FDM extrusion has emerged as a prominent method in manufacturing. However, it encounters certain limitations, notably in surface quality and dimensional accuracy. Addressing issues related to stability and surface roughness necessitates the integration of 3D-printing technology with traditional machining, a strategy known as the hybrid technique. This paper presents a study of the surface geometric parameters and microstructure of plastic parts produced by FDM. Sleeve-shaped samples were 3D-printed from polyethylene terephthalate glycol material using variable layer heights of 0.1 mm and 0.2 mm and then subjected to the turning process with PVD-coated DCMT11T304 turning inserts using variable cutting parameters. The cutting depth was constant at 0.82 mm. Surface roughness values were correlated with the cutting tool feed rate and the printing layer height applied. The selected specimen’s microstructure was studied with a Zeiss EVO MA 15 scanning electron microscope. The roundness was measured with a Keyence VR-6200 3D optical profilometer. The research results confirmed that the additional application of turning, combined with a reduction in the feed rate (0.0506 mm/rev) and the height of the printed layer (0.1 mm), reduced the surface roughness of the sleeve (Ra = 1.94 μm) and increased its geometric accuracy.
Citation: Materials
PubDate: 2024-08-28
DOI: 10.3390/ma17174250
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4251: Effect of Ce Addition on Microstructure,
Thermal Conductivity, and Mechanical Properties of As-Cast and As-Extruded
Mg–3Sn Alloys
Authors: Fei-yu He, Wen-xin Hu, Li-juan Liu, Wei He, Shao-bo Ma, Xu-dong Zhang, Zheng-hua Yang, Wei Wang
First page: 4251
Abstract: In the present research, the impacts of Ce additions at various concentrations (0, 1.0, 3.4, and 4.0 wt.%) on the evolution of the microstructure, mechanical properties, and thermal conductivity of as-cast and as-extruded Mg-3Sn alloys were investigated. The findings demonstrate that adding Ce caused the creation of a new ternary MgSnCe phase in the magnesium matrix. Some new Mg17Ce2 phases are generated in the microstructure when Ce levels reach 4%. The thermal conductivity of the Mg-3Sn alloy is significantly improved due to Ce addition, and the Mg-3Sn-3.4Ce alloy exhibits the highest thermal conductivity, up to 133.8 W/(m·K) at 298 K. After extrusion, both the thermal conductivity and mechanical properties are further improved. The thermal conductivity perpendicular to the extrusion direction of Mg-3Sn-3.4Ce alloy could achieve 136.28 W/(m·K), and the tensile and yield strengths reach 264.3 MPa and 227.2 MPa, with an elongation of 7.9%. Adding Ce decreases the dissolved Sn atoms and breaks the eutectic α-Mg and Mg2Sn network organization, leading to a considerable increase in the thermal conductivity of as-cast Mg-3Sn alloys. Weakening the deformed grain texture contributed to the further enhancement of the thermal conductivity after extrusion.
Citation: Materials
PubDate: 2024-08-28
DOI: 10.3390/ma17174251
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4252: Durability of Magnesium Potassium
Phosphate Cements (MKPCs) under Chemical Attack
Authors: Salma Chhaiba, Sergio Martinez-Sanchez, Nuria Husillos-Rodriguez, Ángel Palomo, Hajime Kinoshita, Inés Garcia-Lodeiro
First page: 4252
Abstract: Magnesium phosphate cements (MPCs), also known as chemically bonded ceramics, represent a class of inorganic cements that have garnered considerable interest in recent years for their exceptional properties and diverse applications in the construction and engineering sectors. However, the development of these cements is relatively recent (they emerged at the beginning of the 20th century), so there are still certain aspects relating to their durability that need to be evaluated. The present work analyses the chemical durability of magnesium potassium phosphate cements (MKPCs) during 1 year of immersion in three leaching media: seawater, a Na2SO4 solution (4% by mass) and deionized water. For this, pastes of prismatic specimens of MKPC, prepared with different M/P ratio (2 and 3), were submitted to the different chemical attacks. At different ages, the changes on the mechanical strengths, microstructure (BSEM, MIP) and mineralogy (XRD, FTIR, TG/DTG) were evaluated. The results obtained indicate that, in general terms, MKPC systems show good behavior in the three media, with the more resistant system being the one prepared with a M/P molar ratio of 3.
Citation: Materials
PubDate: 2024-08-28
DOI: 10.3390/ma17174252
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4253: The Dispersion and Hydration Improvement
of Silica Fume in UHPC by Carboxylic Agents
Authors: Taige Wu, Honghu Wang, Zhidan Rong
First page: 4253
Abstract: Silica fume (SF) is an essential component in ultra-high-performance concrete (UHPC) to compact the matrix, but the nucleus effect also causes rapid hydration, which results in high heat release and large shrinkage. In this paper, the carboxylic agents, including polyacrylic acid and polycarboxylate superplasticizer, were used to surface modify SF to adjust the activity to mitigate hydration at an early time and to promote continuous hydration for a long period. The surface and dispersion properties of modified SF (MSF), as well as the strength and pore structure of UHPC, were studied, and the stability of the modification was also investigated. The results demonstrated that, after treatment, the carboxylic groups were grafted on the SF surface, the dispersion of SF was improved due to the increased negative pentanal of the particle surface and the steric hindrance effect, the early hydration was delayed about 3–5 h, and the hydration heat release was also mitigated. The compressive strength of UHPC with MSF reached a maximum of 138.7 MPa at 3 days, which decreased about 3.7% more than the plain group, while flexural strength varied insignificantly. More pores and cracks were observed in the matrix with MSF, and the hydration degree was promoted with MSF addition. The grafted group on SF fell off under an alkali environment after 1 h.
Citation: Materials
PubDate: 2024-08-28
DOI: 10.3390/ma17174253
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4254: Mercury Ion Selective Adsorption from
Aqueous Solution Using Amino-Functionalized Magnetic Fe2O3/SiO2
Nanocomposite
Authors: Mahmoud M. Youssif, Heba G. El-Attar, Stanisław Małecki, Grzegorz Włoch, Maciej Czapkiewicz, Kamil Kornaus, Marek Wojnicki
First page: 4254
Abstract: This study focuses on the development of new amino-functionalized magnetic Fe2O3/SiO2 nanocomposites with varying silicate shell ratios (1:0.5, 1:1, and 1:2) for the efficient elimination of Hg2+ ions found in solutions. The Fe2O3/SiO2–NH2 adsorbents were characterized for their structural, surface, and magnetic properties using various techniques, including Fourier transform infrared spectrum (FT-IR), powder X-ray diffraction (XRD), scanning electron microscopy (SEM), Braunauer–Emmett–Teller (BET), thermogravimetric analysis (TGA), zeta-potential, and particle size measurement. We investigated the adsorption circumstances, such as pH, dosage of the adsorbent, and duration of adsorption. The pH value that yielded the best results was determined to be 5.0. The Fe2O3/SiO2–NH2 adsorbent with a silicate ratio of (1:2) exhibited the largest amount of adsorption capacity of 152.03 mg g−1. This can be attributed to its significantly large specific surface area of 100.1 m2 g−1, which surpasses that of other adsorbents. The adsorbent with amino functionalization demonstrated a strong affinity for Hg2+ ions due to the chemical interactions between the metal ions and the amino groups on the surface. The analysis of adsorption kinetics demonstrated that the adsorption outcomes adhere to the pseudo-second-order kinetic model. The study of adsorption isotherms revealed that the adsorption followed the Langmuir model, indicating that the adsorption of Hg2+ ions with the adsorbent occurred as a monomolecular layer adsorption process. Furthermore, the thermodynamic analyses revealed that the adsorption of Hg2+ ions using the adsorbent was characterized by a spontaneous and endothermic process. Additionally, the adsorbent has the ability to selectively extract mercury ions from a complex mixture of ions. The Fe2O3/SiO2–NH2 nanocomposite, which is loaded with metal, can be easily recovered from a water solution due to its magnetic properties. Moreover, it can be regenerated effortlessly through acid treatment. This study highlights the potential use of amino-functionalized Fe2O3/SiO2 magnetic nanoparticles as a highly efficient, reusable adsorbent for the removal of mercury ions from contaminated wastewater.
Citation: Materials
PubDate: 2024-08-28
DOI: 10.3390/ma17174254
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4255: A Comprehensive Review of
Stimuli-Responsive Smart Polymer Materials—Recent Advances and
Future Perspectives
Authors: Alicja Balcerak-Woźniak, Monika Dzwonkowska-Zarzycka, Janina Kabatc-Borcz
First page: 4255
Abstract: Today, smart materials are commonly used in various fields of science and technology, such as medicine, electronics, soft robotics, the chemical industry, the automotive field, and many others. Smart polymeric materials hold good promise for the future due to their endless possibilities. This group of advanced materials can be sensitive to changes or the presence of various chemical, physical, and biological stimuli, e.g., light, temperature, pH, magnetic/electric field, pressure, microorganisms, bacteria, viruses, toxic substances, and many others. This review concerns the newest achievements in the area of smart polymeric materials. The recent advances in the designing of stimuli-responsive polymers are described in this paper.
Citation: Materials
PubDate: 2024-08-28
DOI: 10.3390/ma17174255
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4256: Miscibility Studies of Bismesogen CBnCB
Forming Nematic Twist-Bend Phase with Cyanobiphenyls nCB
Authors: Marzena Tykarska, Barbara Klucznik, Jerzy Dziaduszek, Stanisław Jóźwiak
First page: 4256
Abstract: This work aims to determine how the nematic twist-bend phase (NTB) of bismesogens containing two rigid parts of cyanobiphenyls connected with a linking chain containing n = 7, 9, and 11 methylene groups behaves in mixtures with structurally similar cyanobiphenyls nCB, n = 4–12, 14. The whole phase diagrams are presented for the CB7CB-nCB system. For the other systems, CB9CB-nCB and CB11CB-nCB, only curves corresponding to NTB-N phase transition are presented. Based on the temperature-concentration range of the existence of NTB phase, it was established that an increase in the alkyl chain length of CBnCB causes an increase in the stability of the NTB phase. But surprisingly, an increase in the alkyl chain length of nCB compounds does not change the slope of the NTB-N equilibrium line on phase diagrams. It is slightly bigger when the nCB compound has the same length of alkyl chain as the length of the linking group of a bismesogen. XRD studies were carried out for two mixtures.
Citation: Materials
PubDate: 2024-08-28
DOI: 10.3390/ma17174256
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4257: Energy Absorption Behavior of
Carbon-Fiber-Reinforced Plastic Honeycombs under Low-Velocity Impact
Considering Their Ply Characteristics
Authors: Zheng Liu, Kai Zou, Zhendong Zhang
First page: 4257
Abstract: Honeycomb structures made of carbon-fiber-reinforced plastic (CFRP) are increasingly used in the aerospace field due to their excellent energy absorption capability. Attention has been paid to CFRP structures in order to accurately simulate their progressive failure behavior and discuss their ply designability. In this study, the preparation process of a CFRP corrugated sheet (half of the honeycomb structure) and a CFRP honeycomb structure was illustrated. The developed finite element method was verified by a quasi-static test, which was then used to predict the low-velocity impact (LVI) behavior of the CFRP honeycomb, and ultimately, the influence of the ply angle and number on energy absorption was discussed. The results show that the developed finite element method (including the user-defined material subroutine VUMAT) can reproduce the progressive failure behavior of the CFRP corrugated sheet under quasi-static compression and also estimate the LVI behavior. The angle and number of plies of the honeycomb structure have an obvious influence on their energy absorption under LVI. Among them, energy absorption increases with the ply number, but the specific energy absorption is basically constant. The velocity drop ratios for the five different ply angles are 79.12%, 68.49%, 66.88%, 66.86%, and 60.02%, respectively. Therefore, the honeycomb structure with [0/90]s ply angle had the best energy absorption effect. The model proposed in this paper has the potential to significantly reduce experimental expenses, while the research findings can provide valuable technical support for design optimization in aerospace vehicle structures.
Citation: Materials
PubDate: 2024-08-28
DOI: 10.3390/ma17174257
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4258: Analysis of Rheological Properties and
Regeneration Mechanism of Recycled Styrene–Butadiene–Styrene
Block Copolymer (SBS) Modified Asphalt Binder Using Different Rejuvenators
Authors: Hongmei Ma, Fucheng Guo, Jihong Han, Pengfei Zhi
First page: 4258
Abstract: The regeneration performance of an aged styrene–butadiene–styrene block copolymer (SBS) will be significantly influenced by different rejuvenators. The objective of this study was to comparatively investigate the regeneration effect of different SBS-modified asphalt regenerators on aged SBS-modified asphalt. Four types of different regenerant formulations were selected. The optimal rejuvenator content was determined firstly using conventional performance tests. The rheological properties of the aged SBS-modified asphalt binder were evaluated by multiple stress creep recovery (MSCR) experiments. Subsequently, the regeneration mechanism of the SBS-modified asphalt binder was investigated using thin-layer chromatography–flame ionization detection (TLC-FID) and Fourier transform infrared spectroscopy (FTIR). The results showed that the rejuvenator had a certain recovery effect on the penetration, softening point, and ductility of the SBS-modified asphalt binder after aging. The SBS-modified rejuvenating agent was the most favorable among the four types of rejuvenators, where a rejuvenator dosage of 12% showed the optimal rejuvenation effect. The addition of regenerators could appropriately improve the elastic deformation capacity of the aged asphalt binder. The epoxy soybean oil in the regenerant reacted with the aging SBS-modified asphalt binder, supplementing the lost oil in the aged SBS-modified asphalt binder, dispersing the excessive accumulation of asphaltene, and making the residual SBS swell again. The viscoelastic properties of the aging asphalt binder were improved by adjusting the content of components and functional groups to achieve the purpose of regeneration.
Citation: Materials
PubDate: 2024-08-28
DOI: 10.3390/ma17174258
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4259: PCDA/ZnO Organic–Inorganic Hybrid
Photoanode for Efficient Photoelectrochemical Solar Water Splitting
Authors: Nursalim Akhmetzhanov, Mao Zhang, Dongyun Lee, Yoon-Hwae Hwang
First page: 4259
Abstract: In this study, we developed well-aligned ZnO nanoflowers coated with poly-10,12-pentacosadiyonic acid (p-PCDA@ZnO) and modified with Pt nanoparticle (Pt/p-PCDA@ZnO) hybrid photoanodes for highly efficient photoelectrochemical (PEC) water splitting. The scanning electron microscope (SEM) image shows that thin films of the p-PCDA layer were well coated on the ZnO nanoflowers and that Pt nanoparticles were on it. The photoelectrochemical characterizations were made under simulated solar irradiation AM 1.5. The current density of the p-PCDA@ZnO and the Pt/p- PCDA@ZnO was 0.227 mA/cm2 and 0.305 mA/cm2, respectively, and these values were three times and four times higher compared to the 0.071 mA/cm2 of the bare ZnO nanoflowers. The UV–visible spectrum showed that the absorbance of coated p-PCDA films was extended in visible light region, which agrees with the enhanced PEC data for p-PCDA@ZnO. Also, adding Pt nanoparticles on top of the films as co-catalysts enhanced the PEC performance of Pt/p-PCDA@ZnO further. This indicates that Pt/p- PCDA@ZnO has a great potential to be implemented in solar water splitting.
Citation: Materials
PubDate: 2024-08-28
DOI: 10.3390/ma17174259
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4260: Microstructure, Mechanical, and
Tribological Properties of Nb-Doped TiAl Alloys Fabricated via Laser Metal
Deposition
Authors: Kai Huang, Feng Xu, Xinyan Liu, Shiqiu Liu, Qingge Wang, Ian Baker, Min Song, Hong Wu
First page: 4260
Abstract: TiAl alloys possess excellent properties, such as low density, high specific strength, high elastic modulus, and high-temperature creep resistance, which allows their use to replace Ni-based superalloys in some high-temperature applications. In this work, the traditional TiAl alloy Ti-48Al-2Nb-2Cr (Ti4822) was alloyed with additional Nb and fabricated using laser metal deposition (LMD), and the impacts of this additional Nb on the microstructure and mechanical and tribological properties of the as-fabricated alloys were investigated. The resulting alloys mainly consisted of the γ phase, trace β0 and α2 phases. Nb was well distributed throughout the alloys, while Cr segregation resulted in the residual β0 phase. Increasing the amount of Nb content increased the amount of the γ phase and reduced the amount of the β0 phase. The alloy Ti4822-2Nb exhibited a room-temperature (RT) fracture strength under a tensile of 568 ± 7.8 MPa, which was nearly 100 MPa higher than that of the Ti4822-1Nb alloy. A further increase in Nb to an additional 4 at.% Nb had little effect on the fracture strength. Both the friction coefficient and the wear rate increased with the increasing Nb content. The wear mechanisms for all samples were abrasive wear with local plastic deformation and oxidative wear, resulting in the formation of metal oxide particles.
Citation: Materials
PubDate: 2024-08-28
DOI: 10.3390/ma17174260
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4261: Epitaxial Growth of Ga2O3: A Review
Authors: Imteaz Rahaman, Hunter D. Ellis, Cheng Chang, Dinusha Herath Mudiyanselage, Mingfei Xu, Bingcheng Da, Houqiang Fu, Yuji Zhao, Kai Fu
First page: 4261
Abstract: Beta-phase gallium oxide (β-Ga2O3) is a cutting-edge ultrawide bandgap (UWBG) semiconductor, featuring a bandgap energy of around 4.8 eV and a highly critical electric field strength of about 8 MV/cm. These properties make it highly suitable for next-generation power electronics and deep ultraviolet optoelectronics. Key advantages of β-Ga2O3 include the availability of large-size single-crystal bulk native substrates produced from melt and the precise control of n-type doping during both bulk growth and thin-film epitaxy. A comprehensive understanding of the fundamental growth processes, control parameters, and underlying mechanisms is essential to enable scalable manufacturing of high-performance epitaxial structures. This review highlights recent advancements in the epitaxial growth of β-Ga2O3 through various techniques, including Molecular Beam Epitaxy (MBE), Metal-Organic Chemical Vapor Deposition (MOCVD), Hydride Vapor Phase Epitaxy (HVPE), Mist Chemical Vapor Deposition (Mist CVD), Pulsed Laser Deposition (PLD), and Low-Pressure Chemical Vapor Deposition (LPCVD). This review concentrates on the progress of Ga2O3 growth in achieving high growth rates, low defect densities, excellent crystalline quality, and high carrier mobilities through different approaches. It aims to advance the development of device-grade epitaxial Ga2O3 thin films and serves as a crucial resource for researchers and engineers focused on UWBG semiconductors and the future of power electronics.
Citation: Materials
PubDate: 2024-08-28
DOI: 10.3390/ma17174261
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4262: Investigation on Cement-Stabilized Base
with Recycled Aggregate and Desert Sand
Authors: Fengchao Liu, Yongjun Qin, Yiheng Yang
First page: 4262
Abstract: This paper mainly explores the feasibility of using desert sand (DS) and recycled aggregate in cement-stabilized bases. Recycled coarse aggregate (RCA) and DS serve as the substitutes of natural coarse and fine aggregates, respectively, in cement-stabilized bases. A four-factor and four-level orthogonal test is designed to analyze the unconfined compressive strength, splitting tensile strength, and compressive resilient modulus. Furthermore, this paper investigates the effects of cement content, fly ash (FA) replacement rate, RCA replacement rate, and DS replacement rate on the road performance of cement-stabilized bases composed of RCA and DS. The test results reveal that the performance of cement-stabilized bases with partial RCA instead of natural coarse aggregate (NCA) and partial DS instead of natural fine aggregate satisfies the road use. The correlation and microscopic analyses of the test results imply the feasibility of applying DS and recycled aggregate to cement-stabilized bases. This paper calculates and evaluates the life cycle of carbon emissions of desert sand and recycled coarse aggregate cement-stabilized macadam (DRCSM) and finds that both DS and RCA can reduce the carbon emissions of CSM, which has a positive effect on improving the environment and solving the climate crisis. It is hoped that this paper can offer a solid theoretical foundation for promoting the application of DS and recycled aggregate in road engineering.
Citation: Materials
PubDate: 2024-08-28
DOI: 10.3390/ma17174262
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4263: Effect of Extrusion Process on
Microstructure, Corrosion Properties, and Mechanical Properties of
Micro-Alloyed Mg–Zn–Ca–Zr Alloy
Authors: Zemin Yu, Wenxin Hu, Zhiqiang Chen, Lei Shi, Lei Yang, Jianfeng Jin, Erlin Zhang
First page: 4263
Abstract: The effect of the extrusion process on the microstructure, corrosion, and mechanical properties of Mg–Zn–Ca–Zr alloy has been investigated. Zn and Ca were both in a solid solution and only the Zr-rich phase was observed in the homogenized and extruded alloys. The Zr-rich phase was obviously refined after extrusion. The corrosion rate of the homogenized alloy decreased by about 25% after extrusion. This is because the refined Zr-rich phase was easier to cover with the deposited corrosion products, which reduced the cathodic reaction activity of the Zr-rich phase. The corrosion rate is similar for the alloys extruded at 320 °C and 350 °C since the size and distribution of the Zr-rich phase were not different in the two conditions. The alloy extruded at 320 °C has a smaller grain size and better comprehensive mechanical properties.
Citation: Materials
PubDate: 2024-08-28
DOI: 10.3390/ma17174263
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4264: Calcium Silicate-Based Cements in
Restorative Dentistry: Vital Pulp Therapy Clinical, Radiographic, and
Histological Outcomes on Deciduous and Permanent Dentition—A
Systematic Review and Meta-Analysis
Authors: Maria Teresa Xavier, Ana Luísa Costa, João Carlos Ramos, João Caramês, Duarte Marques, Jorge N. R. Martins
First page: 4264
Abstract: Vital pulp therapy aims to preserve the vitality of dental pulp exposed due to caries, trauma, or restorative procedures. The aim of the present review was to evaluate the clinical, radiographic, and histological outcomes of different calcium silicate-based cements used in vital pulp therapy for both primary and permanent teeth. The review included 40 randomized controlled trials from a search across PubMed, LILACS, and the Cochrane Collaboration, as well as manual searches and author inquiries according to specific inclusion and exclusion criteria. A critical assessment of studies was conducted, and after data extraction the results were submitted to a quantitative statistical analysis using meta-analysis. The studies, involving 1701 patients and 3168 teeth, compared a total of 18 different calcium silicate-based cements in both dentitions. The qualitative synthesis showed no significant differences in short-term outcomes (up to 6 months) between different calcium silicate-based cements in primary teeth. ProRoot MTA and Biodentine showed similar clinical and radiographic success rates at 6 and 12 months. In permanent teeth, although the global results appeared to be well balanced, ProRoot MTA generally seemed to perform better than other calcium silicate-based cements except for Biodentine, which had comparable or superior results at 6 months. Meta-analyses for selected comparisons showed no significant differences in clinical and radiographic outcomes between ProRoot MTA and Biodentine over follow-up periods. The present review highlights the need for standardized definitions of success and follow-up periods in future studies to better guide clinical decisions. Despite the introduction of new calcium silicate-based cements aiming to address limitations of the original MTA. ProRoot MTA and Biodentine remain the most used and reliable materials for vital pulp therapy, although the results did not deviate that much from the other calcium silicate-based cements. Further long-term studies are required to establish the optimal CSC for each clinical scenario in both dentitions.
Citation: Materials
PubDate: 2024-08-28
DOI: 10.3390/ma17174264
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4265: Improvement of Hydrogen-Resistant Gas
Authors: Alexander I. Balitskii, Yulia H. Kvasnytska, Ljubomyr M. Ivaskevych, Katrine H. Kvasnytska, Olexiy A. Balitskii, Radoslaw M. Miskiewicz, Volodymyr O. Noha, Zhanna V. Parkhomchuk, Valentyn I. Veis, Jakub Maciej Dowejko
First page: 4265
Abstract: This paper presents the results of an analysis of resistance to hydrogen embrittlement and offers solutions and technologies for manufacturing castings of components for critical applications, such as blades for gas turbine engines (GTEs). The values of the technological parameters for directional crystallization (DC) are determined, allowing the production of castings with a regular dendritic structure of the crystallization front in the range of 10 to 12 mm/min and a temperature gradient at the crystallization front in the range of 165–175 °C/cm. The technological process of making GTE blades has been improved by using a scheme for obtaining disposable models of complex profile castings with the use of 3D printing for the manufacture of ceramic molds. The ceramic mold is obtained through an environmentally friendly technology using water-based binders. Short-term tensile testing of the samples in gaseous hydrogen revealed high hydrogen resistance of the CM-88 alloy produced by directed crystallization technology: the relative elongation in hydrogen at a pressure of 30 MPa increased from 2% for the commercial alloy to 8% for the experimental single-crystal alloy.
Citation: Materials
PubDate: 2024-08-28
DOI: 10.3390/ma17174265
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4266: Low-Cycle Fatigue Damage Mechanism and
Life Prediction of High-Strength Compacted Graphite Cast Iron at Different
Temperatures
Authors: Qihua Wu, Bingzhi Tan, Jianchao Pang, Feng Shi, Ailong Jiang, Chenglu Zou, Yunji Zhang, Shouxin Li, Yanyan Zhang, Xiaowu Li, Zhefeng Zhang
First page: 4266
Abstract: Tensile and low-cycle fatigue tests of high-strength compacted graphite cast iron (CGI, RuT450) were carried out at 25 °C, 400 °C, and 500 °C, respectively. The results show that with the increase in temperature, the tensile strength decreases slowly and then decreases rapidly. The fatigue life decreases, and the life reduction increases at high temperature and high strain amplitude. The oxide layer appears around the graphite and cracks at high temperature, and the dependence of crack propagation on ferrite gradually decreases. With the increase in strain amplitude, the initial cyclic stress of compacted graphite cast iron increases at three temperatures, and the cyclic hardening phenomenon is obvious. The fatigue life prediction method based on the energy method and damage mechanism for compacted graphite cast iron is summarized and proposed after comparing and analyzing a large amount of fatigue data.
Citation: Materials
PubDate: 2024-08-28
DOI: 10.3390/ma17174266
Issue No: Vol. 17, No. 17 (2024)
- Materials, Vol. 17, Pages 4267: Structure–Dopant Concentration
Relations in Europium-Doped Yttrium Molybdate and Peak-Sharpening for
Luminescence Temperature Sensing
Authors: Tamara Gavrilović, Aleksandar Ćirić, Mina Medić, Zoran Ristić, Jovana Periša, Željka Antić, Miroslav D. Dramićanin
First page: 4267
Abstract: A set of Eu3+-doped molybdates, Y2−xEuxMo3O12 (x = 0.04; 0.16; 0.2; 0.4; 0.8; 1; 1.6; 2), was synthesized using a solid-state technique and their properties studied as a function of Eu3+ concentration. X-ray diffraction showed that the replacement of Y3+ with larger Eu3+ resulted in a transformation from orthorhombic (low doping concentrations) through tetragonal (high doping concentrations), reaching monoclinic structure for full replacement in Eu2Mo3O12. The intensity of typical Eu3+ red emission slightly increases in the orthorhombic structure then rises significantly with dopant concentration and has the highest value for the tetragonal Y2Mo3O12:80mol% Eu3+. Further, the complete substitution of Y3+ with Eu3+ in the case of monoclinic Eu2Mo3O12 leads to decreased emission intensity. Lifetime follows a similar trend; it is lower in the orthorhombic structure, reaching slightly higher values for the tetragonal structure and showing a strong decrease for monoclinic Eu2Mo3O12. Temperature-sensing properties of the sample with the highest red Eu3+ emission, Y2Mo3O12:80mol% Eu3+, were analyzed by the luminescence intensity ratio method. For the first time, the peak-sharpening algorithm was employed to separate overlapping peaks in luminescence thermometry, in contrast to the peak deconvolution method. The Sr (relative sensitivity) value of 2.8 % K−1 was obtained at room temperature.
Citation: Materials
PubDate: 2024-08-28
DOI: 10.3390/ma17174267
Issue No: Vol. 17, No. 17 (2024)
