Subjects -> CHEMISTRY (Total: 1001 journals)
    - ANALYTICAL CHEMISTRY (59 journals)
    - CHEMISTRY (726 journals)
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CHEMISTRY (726 journals)                  1 2 3 4 | Last

Showing 1 - 200 of 735 Journals sorted alphabetically
Accounts of Materials Research     Hybrid Journal  
Accreditation and Quality Assurance: Journal for Quality, Comparability and Reliability in Chemical Measurement     Hybrid Journal   (Followers: 36)
ACS Applied Polymer Materials     Hybrid Journal   (Followers: 15)
ACS Catalysis     Hybrid Journal   (Followers: 78)
ACS Chemical Neuroscience     Hybrid Journal   (Followers: 25)
ACS Combinatorial Science     Hybrid Journal   (Followers: 25)
ACS Macro Letters     Hybrid Journal   (Followers: 34)
ACS Materials Letters     Open Access   (Followers: 4)
ACS Medicinal Chemistry Letters     Hybrid Journal   (Followers: 49)
ACS Nano     Hybrid Journal   (Followers: 452)
ACS Photonics     Hybrid Journal   (Followers: 19)
ACS Symposium Series     Full-text available via subscription   (Followers: 3)
ACS Synthetic Biology     Hybrid Journal   (Followers: 40)
Acta Chemica Iasi     Open Access   (Followers: 8)
Acta Chemica Malaysia     Open Access  
Acta Chimica Slovaca     Open Access   (Followers: 4)
Acta Chimica Slovenica     Open Access   (Followers: 2)
Acta Chromatographica     Full-text available via subscription   (Followers: 9)
Acta Facultatis Medicae Naissensis     Open Access   (Followers: 1)
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 10)
Acta Scientifica Naturalis     Open Access   (Followers: 3)
adhäsion KLEBEN & DICHTEN     Hybrid Journal   (Followers: 9)
Adhesion Adhesives & Sealants     Hybrid Journal   (Followers: 10)
Adsorption Science & Technology     Open Access   (Followers: 9)
Advanced Electronic Materials     Hybrid Journal   (Followers: 7)
Advanced Functional Materials     Hybrid Journal   (Followers: 81)
Advanced Journal of Chemistry, Section A     Open Access   (Followers: 15)
Advanced Journal of Chemistry, Section B     Open Access   (Followers: 14)
Advanced Science Focus     Free   (Followers: 7)
Advanced Theory and Simulations     Hybrid Journal   (Followers: 5)
Advanced Therapeutics     Hybrid Journal   (Followers: 1)
Advances in Chemical Engineering and Science     Open Access   (Followers: 108)
Advances in Chemical Science     Open Access   (Followers: 50)
Advances in Chemistry     Open Access   (Followers: 39)
Advances in Chemistry     Full-text available via subscription   (Followers: 6)
Advances in Colloid and Interface Science     Full-text available via subscription   (Followers: 21)
Advances in Drug Research     Full-text available via subscription   (Followers: 27)
Advances in Environmental Chemistry     Open Access   (Followers: 11)
Advances in Enzyme Research     Open Access   (Followers: 13)
Advances in Fluorine Science     Full-text available via subscription   (Followers: 8)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 20)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 11)
Advances in Materials Physics and Chemistry     Open Access   (Followers: 35)
Advances in Nanoparticles     Open Access   (Followers: 20)
Advances in Organometallic Chemistry     Full-text available via subscription   (Followers: 20)
Advances in Polymer Science     Hybrid Journal   (Followers: 54)
Advances in Protein Chemistry     Full-text available via subscription   (Followers: 19)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 22)
Advances in Quantum Chemistry     Full-text available via subscription   (Followers: 7)
Advances in Science and Technology     Full-text available via subscription   (Followers: 17)
Aerosol Science and Engineering     Hybrid Journal  
African Journal of Bacteriology Research     Open Access  
African Journal of Chemical Education     Open Access   (Followers: 6)
African Journal of Pure and Applied Chemistry     Open Access   (Followers: 7)
Aggregate     Open Access   (Followers: 3)
Agrokémia és Talajtan     Full-text available via subscription   (Followers: 3)
Al-Kimia : Jurnal Penelitian Sains Kimia     Open Access  
Alchemy : Journal of Chemistry     Open Access   (Followers: 5)
Alchemy : Jurnal Penelitian Kimia     Open Access   (Followers: 2)
Alkaloids: Chemical and Biological Perspectives     Full-text available via subscription   (Followers: 2)
Alotrop     Open Access  
AMB Express     Open Access   (Followers: 1)
Ambix     Hybrid Journal   (Followers: 3)
American Journal of Biochemistry and Biotechnology     Open Access   (Followers: 71)
American Journal of Biochemistry and Molecular Biology     Open Access   (Followers: 24)
American Journal of Chemistry     Open Access   (Followers: 41)
American Journal of Plant Physiology     Open Access   (Followers: 13)
Analyst     Full-text available via subscription   (Followers: 40)
Analytical Science Advances     Open Access   (Followers: 2)
Angewandte Chemie     Hybrid Journal   (Followers: 237)
Angewandte Chemie International Edition     Hybrid Journal   (Followers: 354)
Annales Universitatis Mariae Curie-Sklodowska, sectio AA – Chemia     Open Access   (Followers: 1)
Annals of Clinical Chemistry and Laboratory Medicine     Open Access   (Followers: 8)
Annual Reports in Computational Chemistry     Full-text available via subscription   (Followers: 4)
Annual Reports Section A (Inorganic Chemistry)     Full-text available via subscription   (Followers: 6)
Annual Reports Section B (Organic Chemistry)     Full-text available via subscription   (Followers: 9)
Annual Review of Chemical and Biomolecular Engineering     Full-text available via subscription   (Followers: 13)
Annual Review of Food Science and Technology     Full-text available via subscription   (Followers: 16)
Antiviral Chemistry and Chemotherapy     Open Access   (Followers: 2)
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 12)
Applied Spectroscopy     Full-text available via subscription   (Followers: 27)
Applied Surface Science     Hybrid Journal   (Followers: 33)
Arabian Journal of Chemistry     Open Access   (Followers: 6)
ARKIVOC     Open Access   (Followers: 1)
Asian Journal of Applied Chemistry Research     Open Access   (Followers: 2)
Asian Journal of Biochemistry     Open Access   (Followers: 3)
Asian Journal of Chemical Sciences     Open Access   (Followers: 1)
Asian Journal of Chemistry and Pharmaceutical Sciences     Open Access   (Followers: 2)
Asian Journal of Physical and Chemical Sciences     Open Access   (Followers: 3)
Atomization and Sprays     Full-text available via subscription   (Followers: 8)
Australian Journal of Chemistry     Hybrid Journal   (Followers: 7)
Autophagy     Hybrid Journal   (Followers: 7)
Avances en Quimica     Open Access  
Biochemical Pharmacology     Hybrid Journal   (Followers: 11)
Biochemistry     Hybrid Journal   (Followers: 486)
Biochemistry Insights     Open Access   (Followers: 7)
Biochemistry Research International     Open Access   (Followers: 6)
BioChip Journal     Hybrid Journal  
Bioinorganic Chemistry and Applications     Open Access   (Followers: 11)
Biointerface Research in Applied Chemistry     Open Access   (Followers: 3)
Biointerphases     Open Access   (Followers: 1)
Biology, Medicine, & Natural Product Chemistry     Open Access   (Followers: 4)
Biomacromolecules     Hybrid Journal   (Followers: 27)
Biomass Conversion and Biorefinery     Partially Free   (Followers: 11)
Biomedical Chromatography     Hybrid Journal   (Followers: 6)
Biomolecular NMR Assignments     Hybrid Journal   (Followers: 4)
BioNanoScience     Partially Free   (Followers: 6)
Bioorganic & Medicinal Chemistry     Hybrid Journal   (Followers: 217)
Bioorganic & Medicinal Chemistry Letters     Hybrid Journal   (Followers: 88)
Bioorganic Chemistry     Hybrid Journal   (Followers: 10)
Biopolymers     Hybrid Journal   (Followers: 18)
Biosensors     Open Access   (Followers: 4)
Biotechnic and Histochemistry     Hybrid Journal   (Followers: 1)
Bitácora Digital     Open Access  
Boletin de la Sociedad Chilena de Quimica     Open Access  
Bulletin of Institute of Chemistry and Chemical Technology, Mongolian Academy of Sciences     Open Access  
Bulletin of the Chemical Society of Ethiopia     Open Access   (Followers: 1)
Bulletin of the Chemical Society of Japan     Full-text available via subscription   (Followers: 26)
Bulletin of the Korean Chemical Society     Hybrid Journal   (Followers: 1)
C - Journal of Carbon Research     Open Access   (Followers: 5)
Cakra Kimia (Indonesian E-Journal of Applied Chemistry)     Open Access  
Canadian Association of Radiologists Journal     Full-text available via subscription   (Followers: 2)
Canadian Journal of Chemistry     Hybrid Journal   (Followers: 13)
Canadian Mineralogist     Full-text available via subscription   (Followers: 7)
Carbohydrate Polymer Technologies and Applications     Open Access   (Followers: 3)
Carbohydrate Polymers     Hybrid Journal   (Followers: 13)
Carbohydrate Research     Hybrid Journal   (Followers: 26)
Carbon     Hybrid Journal   (Followers: 76)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 9)
Catalysis Science and Technology     Hybrid Journal   (Followers: 13)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 4)
Catalysts     Open Access   (Followers: 14)
Cell Reports Physical Science     Open Access  
Cellulose     Hybrid Journal   (Followers: 17)
Cereal Chemistry     Full-text available via subscription   (Followers: 6)
ChemBioEng Reviews     Full-text available via subscription   (Followers: 3)
ChemCatChem     Hybrid Journal   (Followers: 11)
Chemical and Engineering News     Free   (Followers: 24)
Chemical Bulletin of Kazakh National University     Open Access  
Chemical Communications     Full-text available via subscription   (Followers: 88)
Chemical Engineering Research and Design     Hybrid Journal   (Followers: 28)
Chemical Physics Letters : X     Open Access   (Followers: 4)
Chemical Research in Chinese Universities     Hybrid Journal   (Followers: 4)
Chemical Research in Toxicology     Hybrid Journal   (Followers: 25)
Chemical Reviews     Hybrid Journal   (Followers: 267)
Chemical Science     Open Access   (Followers: 44)
Chemical Science International Journal     Open Access   (Followers: 1)
Chemical Technology     Open Access   (Followers: 71)
Chemical Vapor Deposition     Hybrid Journal   (Followers: 5)
Chemie in Unserer Zeit     Hybrid Journal   (Followers: 56)
Chemie-Ingenieur-Technik (Cit)     Hybrid Journal   (Followers: 23)
ChemInform     Hybrid Journal   (Followers: 9)
Chemistry     Open Access  
Chemistry & Biodiversity     Hybrid Journal   (Followers: 7)
Chemistry & Biology     Full-text available via subscription   (Followers: 31)
Chemistry & Industry     Full-text available via subscription   (Followers: 8)
Chemistry - A European Journal     Hybrid Journal   (Followers: 225)
Chemistry - An Asian Journal     Hybrid Journal   (Followers: 20)
Chemistry Africa : A Journal of the Tunisian Chemical Society     Hybrid Journal  
Chemistry and Materials Research     Open Access   (Followers: 24)
Chemistry Central Journal     Open Access   (Followers: 5)
Chemistry Education Research and Practice     Free   (Followers: 8)
Chemistry Education Review     Open Access   (Followers: 5)
Chemistry in Education     Open Access   (Followers: 9)
Chemistry Letters     Full-text available via subscription   (Followers: 49)
Chemistry of Heterocyclic Compounds     Hybrid Journal   (Followers: 4)
Chemistry of Materials     Hybrid Journal   (Followers: 338)
Chemistry of Natural Compounds     Hybrid Journal   (Followers: 10)
Chemistry World     Full-text available via subscription   (Followers: 20)
Chemistry-Didactics-Ecology-Metrology     Open Access   (Followers: 1)
ChemistryOpen     Open Access   (Followers: 1)
ChemistrySelect     Hybrid Journal  
Chemistry–Methods     Open Access   (Followers: 2)
Chemkon - Chemie Konkret, Forum Fuer Unterricht Und Didaktik     Hybrid Journal  
ChemNanoMat     Hybrid Journal   (Followers: 1)
Chemoecology     Hybrid Journal   (Followers: 3)
Chemometrics and Intelligent Laboratory Systems     Hybrid Journal   (Followers: 14)
Chemosensors     Open Access   (Followers: 1)
ChemPhotoChem     Hybrid Journal  
ChemPhysChem     Hybrid Journal   (Followers: 14)
ChemPlusChem     Hybrid Journal   (Followers: 2)
Chempublish Journal     Open Access   (Followers: 1)
ChemSystemsChem     Hybrid Journal   (Followers: 2)
ChemTexts     Hybrid Journal   (Followers: 1)
CHIMIA International Journal for Chemistry     Open Access   (Followers: 2)
Chinese Journal of Chemistry     Hybrid Journal   (Followers: 6)
Chinese Journal of Polymer Science     Hybrid Journal   (Followers: 13)
Chromatographia     Hybrid Journal   (Followers: 22)
Chromatography     Open Access   (Followers: 3)
Chromatography Research International     Open Access   (Followers: 5)
Ciencia     Open Access   (Followers: 1)
Clay Minerals     Hybrid Journal   (Followers: 9)
Cogent Chemistry     Open Access   (Followers: 3)
Colloid and Interface Science Communications     Open Access  
Colloid and Polymer Science     Hybrid Journal   (Followers: 12)
Colloids and Interfaces     Open Access  
Colloids and Surfaces B: Biointerfaces     Hybrid Journal   (Followers: 8)
Combinatorial Chemistry & High Throughput Screening     Hybrid Journal   (Followers: 4)
Combustion Science and Technology     Hybrid Journal   (Followers: 25)
Comments on Inorganic Chemistry: A Journal of Critical Discussion of the Current Literature     Hybrid Journal   (Followers: 2)

        1 2 3 4 | Last

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Acta Metallurgica Sinica (English Letters)
Journal Prestige (SJR): 0.576
Citation Impact (citeScore): 2
Number of Followers: 10  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1006-7191 - ISSN (Online) 2194-1289
Published by Springer-Verlag Homepage  [2658 journals]
  • Effects of Chromium on the Microstructures and Mechanical Properties of
           AlCoCrxFeNi2.1 Eutectic High Entropy Alloys

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      Abstract: In the present study, a series of AlCoCrxFeNi2.1 (x = 0, 0.25, 0.5, 0.75, 1.0) eutectic high entropy alloys (EHEAs) have been designed and prepared. And the effect of Cr content on the microstructures and mechanical properties of the AlCoCrxFeNi2.1 alloys was systematically investigated. The results indicate that the AlCoCrxFeNi2.1 (x > 0) alloys exhibit almost complete lamellar eutectic microstructures with a mixture structure of FCC and B2 phases. And the AlCoFeNi2.1 alloy without Cr element exhibited a hypoeutectic microstructure with a primary B2 phase. In addition, the eutectic microstructures for AlCoCrxFeNi2.1 eutectic alloys do not change significantly. The room temperature compressive tests results show that with an increase in Cr content (from x = 0 to x = 1.0), the yield strength will first decrease, and thereafter increase. The trend is the opposite with the fracture strength and plastic strain. They show an increase trend at first, and then decrease. The AlCoCr0.5FeNi2.1 (Cr0.5) alloy shows the best comprehensive mechanical properties. The tensile yield strength, fracture strength, and elongation are 536.5 MPa, 1062 MPa, and 13.8%, respectively. Furthermore, the Cr0.5 alloy also displays a high strength with a yield strength of 362 MPa at 700 ºC. In summary, by changing the Cr content, AlCoCrxFeNi2.1 eutectic high entropy alloys with excellent comprehensive mechanical properties were obtained and prepared.
      PubDate: 2021-11-01
       
  • Hot Deformation and Subsequent Annealing on the Microstructure and
           Hardness of an Al0.3CoCrFeNi High-entropy Alloy

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      Abstract: The influence of simple thermomechanical processing such as hot deformation and heat treatment on the microstructure and hardness of an Al0.3CoCrFeNi high-entropy alloy has been investigated. Results show that the relatively high deformation temperature can induce discontinuous dynamic recrystallization with fine grains initially nucleating at the elongated grain boundaries. The transition from partial recrystallization to fully recrystallization, as well as the precipitation behavior after annealing, has been described in detail. Both bcc precipitation and completely recrystallized grains can be observed after annealing at 1000 °C. Based on detailed microstructure analysis, the decrease in hardness value is shown to be related to both dynamic recrystallization and dynamic recovery which lead to softening.
      PubDate: 2021-11-01
       
  • A Novel CoFe2NiMn0.3AlCux High-Entropy Alloy with Excellent Magnetic
           Properties and Good Mechanical Properties

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      Abstract: In the present study, we investigate the crystal structure of high-entropy alloys (HEAs) in the form of CoFe2NiMn0.3AlCux (x = 0.25, 0.50, 0.75, and 1.00) and their mechanical and magnetic properties. The CoFe2NiMn0.3AlCux alloys are composed of a mixture of a body-centered cubic (BCC) and a face-centered cubic (FCC) solid solution. The increased amounts of copper (Cu) boost both alloy strength and plastic ductility. The CoFe2NiMn0.3AlCu1.0 HEAs demonstrate excellent mechanical properties, such as a high strength of 1832 MPa and a large plastic ductility of 22.38%. Magnetic property measurements on this alloy system indicated high saturated magnetization and high coercivity. The coercivity of the tested alloys lies in the range between 40 and 182 Oe, suggesting that the alloys have semi-hard magnetic properties. This study suggests that the present CoFe2NiMn0.3AlCux HEAs could serve as potential candidates for soft magnets in electromagnetic applications.
      PubDate: 2021-11-01
       
  • Revealing the Local Microstates of Fe–Mn–Al Medium Entropy Alloy: A
           Comprehensive First-principles Study

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      Abstract: Entropy-stabilized multi-component alloys have been considered to be prospective structural materials attributing to their impressive mechanical and functional properties. The local chemical complexions, microstates and configurational transformations are essential to reveal the structure–property relationship, thus, to promote the development of advanced multi-component alloys. In the present work, effects of local lattice distortion (LLD) and microstates of various configurations on the equilibrium volume (V0), total energy, Fermi energy, magnetic moment (μMag) and electron work function (Φ) and bonding structures of the Fe–Mn–Al medium entropy alloy (MEA) have been investigated comprehensively by first-principles calculations. It is found that the Φ and μMag of those MEA are proportional to the V0, which is dominated by lattice distortion. In terms of bonding charge density, both the strengthened clusters or the so-called short-range order structures and the weakly bonded spots or weak spots are characterized. While the presence of weakly bonded Al atoms implies a large LLD/mismatch, the Fe–Mn bonding pairs result in the formation of strengthened clusters, which dominate the local microstates and the configurational transitions. The variations of μMag are associated with the enhancement of the nearest neighbor magnetic Fe and Mn atoms, attributing to the LLD caused by Al atoms, the local changes in the electronic structures. This work provides an atomic and electronic insight into the microstate-dominated solid-solution strengthening mechanism of Fe–Mn–Al MEA.
      PubDate: 2021-11-01
       
  • Mechanical Properties and Phase Stability of WTaMoNbTi Refractory
           High-Entropy Alloy at Elevated Temperatures

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      Abstract: High-temperature structural metals remain in high demand for aerospace aircraft, gas turbine engines, and nuclear power plants. Refractory high-entropy alloys (RHEAs) with superior mechanical properties at elevated temperatures are promising candidates for high-temperature structural materials. In this work, a WTaMoNbTi RHEA with adequate room temperature plasticity and considerable strength at 1600 °C was fabricated by vacuum arc-melting. The room temperature fracture strain of the as-cast WTaMoNbTi RHEA was 7.8%, which was about 5.2 times that of the NbMoTaW alloy. The alloy exhibited a strong resistance to high-temperature softening, with a high yield strength of 173 MPa and compressive strength of 218 MPa at 1600 °C. The WTaMoNbTi RHEA possessed excellent phase stability in the range of room temperature to 2000 °C. The dendritic grains grew into equiaxed grains after compression test at 1600 °C due to the dynamic recrystallization process at high temperature. This work presents a promising high-temperature structural material that can be applied at 1600 °C.
      PubDate: 2021-11-01
       
  • Characterization of Nucleation Behavior in Temperature-Induced BCC-to-HCP
           Phase Transformation for High Entropy Alloy

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      Abstract: Phase transformation is one of the essential topics in the studies on high entropy alloys (HEAs). However, characterization of the nucleation behavior in the phase transformation for HEAs is still challenging through experimental methods. In the present work, HfNbTaTiZr HEA was chosen as the representative material, and molecular dynamics/Monte Carlo (MD/MC) simulations were performed to investigate the nucleation behavior in temperature-induced BCC-to-HCP transformation for this HEA system. The results indicate that Nb–Ta, Ti–Zr, Hf–Zr and Hf–Ti atom pairs are preferred in the BCC solid solution of HfNbTaTiZr HEA and Hf–Ti–Zr-rich atom cluster with chemical short range order acts as the nucleation site for HCP phase. The nucleation process follows the non-classical two-step nucleation model: BCC-like structure with severe lattice distortion forms first and then HCP structure nucleates from the BCC-like structure. Moreover, at low temperature, the BCC-to-HCP nucleation hardly occurs, and the BCC solid solution is stabilized. The present work provides more atomic details of the nucleation behavior in temperature-induced BCC-to-HCP phase transformation for HEA, and can help in deep understanding of the phase stability for HEAs.
      PubDate: 2021-11-01
       
  • Ageing Hardening Mechanism and Corrosion Resistance in the
           Fe65Cr13Cu3(CoMnMoNiAlTi)19 Medium-Entropy Stainless Alloy

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      Abstract: The ageing hardening mechanism of a newly designed Fe–Cr-based Fe65Cr13Cu3(CoMnMoNiAlTi)19 medium-entropy stainless alloy (ME-SA) with a simple bcc solid solution matrix was studied. This kind of ME-SA possessed a higher ageing hardness of approximately 584 HV and higher compressive stress and corrosion resistance than those of the conventional precipitation hardening stainless steel 17-4PH (Cr17Ni4Cu4Nb), which has comparable compressive strain. The well-dispersed B2-ordered phase in the cast state transformed to a D03 crystal structure with a higher ordering degree and reduced the precipitate size after ageing at 500 °C, thus promoting a great ageing hardening effect.
      PubDate: 2021-11-01
       
  • Relation Between Strength and Hardness of High-Entropy Alloys

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      Abstract: High-entropy alloys (HEAs) are composed of multiple principal elements and exhibit not only remarkable mechanical properties, but also promising potentials for developing numerous new compositions. To fully realize such potentials, high-throughput preparation and characterization technologies are especially useful; thereby, the fast evaluations of mechanical properties will be urgently required. Revealing the relation between strength and hardness is of significance for quickly predicting the strength of materials through simple hardness testing. However, up to now the strength–hardness relation for HEAs is still a puzzle. In this work, the relations between tensile or compressive strength and Vickers hardness of various HEAs with hundreds of compositions at room temperature are investigated, and finally, the solution for estimating the strengths of HEAs from their hardness values is achieved. Data for hundreds of different HEAs were extracted from studies reported in the period from 2010 to 2020. The results suggested that the well-known three-time relation (i.e., hardness equals to three times the magnitude of strength) works for nearly all HEAs, except for a few brittle HEAs which show quite high hardness but low strength due to early fracture. However, for HEAs with different phase structures, different strengths should be applied in using the 3-time relation, i.e., yield strength for low ductility body-centered cubic (BCC) HEAs and ultimate strength for highly plastic and work-hardenable face-centered cubic (FCC) HEAs. As for dual-phase or multi-phase HEAs, similar 3-time relations can be also found. The present approach sheds light on the mechanisms of hardness and also provides useful guidelines for quick estimation of strength from hardness for various HEAs.
      PubDate: 2021-11-01
       
  • Effect of Cu-Rich Phase Precipitation on the Microstructure and Mechanical
           Properties of CoCrNiCux Medium-Entropy Alloys Prepared via Laser Directed
           Energy Deposition

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      Abstract: CoCrNiCux (x = 0.16, 0.33, 0.75, and 1) without macro-segregation medium-entropy alloys (MEAs) was prepared using laser directed energy deposition (LDED). The microstructure and mechanical properties of CoCrNiCux alloys with increasing Cu content were investigated. The results indicate that a single matrix phase changes into a dual-phase structure and the tensile fracture behaviors convert from brittle to plastic pattern with increasing Cu content in CoCrNiCux alloys. In addition, the tensile strength of CoCrNiCux alloys increased from 148 to 820 MPa, and the ductility increased from 1 to 11% with increasing Cu content. The nano-precipitated particles had a mean size of approximately 20 nm in the Cu-rich phase area, and a large number of neatly arranged misfit dislocations were observed at the interface between the two phases due to Cu-rich phase precipitation in the CoCrNiCu alloy. These misfit dislocations hinder the movement of dislocations during tensile deformation, as observed through transmission electron microscopy. This allows the CoCrNiCu alloy to reach the largest tensile strength and plasticity, and a new strengthening mechanism was achieved for the CoCrNiCu alloy. Moreover, twins were observed in the matrix phase after tensile fracture. Simultaneously, the dual-phase structure with different elastic moduli coordinated with each other during the deformation process, significantly improving the plasticity and strength of the CoCrNiCu alloy.
      PubDate: 2021-11-01
       
  • A Novel High-Entropy Amorphous Thin Film with High Electrical Resistivity
           and Outstanding Corrosion Resistance

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      Abstract: This study explores a novel WNbMoTaV high-entropy thin film (HETF) in amorphous structure via pulsed laser deposition system. The formation of amorphous structure of this high-entropy alloy is ascribed to the high cooling rate during the deposition process. The HETF shows a smooth surface with a height fluctuation of less than 13 nm. This film has a high electrical resistivity of ~ 320.6 μΩ∙cm and a low corrosion current density of 0.088 μA/cm2. The corrosion resistance of the HETF at ambient temperature is superior to the conventional AISI 316L stainless steel. The high electrical resistivity and excellent corrosion resistance of the HETF are mainly attributed to its chemical disorder, cocktail effect and homogeneous amorphous structure. This experimental phenomenon not only provides a basis for the preparation of amorphous alloy films with low glass forming ability by pulsed laser deposition system, also promotes the potential application of WNbMoTaV HETF in the microelectronic components as resistivity sensors.
      PubDate: 2021-11-01
       
  • Relationship of Corrosion Behavior Between Single-Phase Equiatomic CoCrNi,
           CoCrNiFe, CoCrNiFeMn Alloys and Their Constituents in NaCl Solution

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      Abstract: The composition is a significant issue for corrosion resistance of metallic materials. To reveal the correlation of corrosion behavior between multiprinciple alloys and their constituents, a series of single-phase equiatomic alloys of CoCrNi, CoCrNiFe and CoCrNiFeMn was fabricated. The electrochemical and scanning electron microscope results demonstrated that corrosion resistance of the equiatomic alloys in 0.1 M NaCl solution is located in the range but not the average value of their constituents. X-ray photoelectron spectroscopy analysis indicated that the protective performance of passive film is mainly determined by the constituent with the highest corrosion resistance and the breakdown of passive film is mainly dominated by the elements with the highest corrosion rate. Our findings can guide the materials design of multiprinciple alloys with expected corrosion performance.
      PubDate: 2021-11-01
       
  • Orientation-Dependent Mechanical Responses and Plastic Deformation
           Mechanisms of FeMnCoCrNi High-entropy Alloy: A Molecular Dynamics Study

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      Abstract: Mechanical properties of high-entropy alloys (HEAs) with the face-centered cubic (fcc) structure strongly depend on their initial grain orientations. However, the orientation-dependent mechanical responses and the underlying plastic flow mechanisms of such alloys are not yet well understood. Here, deformation of the equiatomic FeMnCoCrNi HEA with various initial orientations under uniaxial tensile testing has been studied by using atomistic simulations, showing the results consistent with the recent experiments on fcc HEAs. The quantitative analysis of the activated deformation modes shows that the initiation of stacking faults is the main plastic deformation mechanism for the crystals initially oriented with [001], [111], and [112], and the total dislocation densities in these crystals are higher than that with the [110] and [123] orientations. Stacking faults, twinning, and hcp-martensitic transformation jointly promote the plastic deformation of the [110] orientation, and twinning in this crystal is more significant than that with other orientations. Deformation in the crystal oriented with [123] is dominated by the hcp-martensite transformation. Comparison of the mechanical behaviors in the FeMnCoCrNi alloy and the conventional materials, i.e. Cu and Fe50Ni50, has shown that dislocation slip tends to be activated more readily in the HEA. This is attributed to the larger lattice distortion in the HEA than the low-entropy materials, leading to the lower critical stress for dislocation nucleation and elastic–plastic transition in the former. In addition, the FeMnCoCrNi HEA with the larger lattice distortion leads to an enhanced capacity of storing dislocations. However, for the [001]-oriented HEA in which dislocation slip and stacking fault are the dominant deformation mechanisms, the limited deformation modes activated are insufficient to improve the work hardening ability of the material.
      PubDate: 2021-11-01
       
  • Heterogeneous Structure Design to Strengthen Carbon-Containing CoCrFeNi
           High Entropy Alloy

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      Abstract: A carbon-containing CoCrFeNi high entropy alloy (HEA) with heterogeneous structures was obtained through thermomechanical treatments, which induced concurrent recrystallization and carbide precipitation in the alloy. A combination of high yield strength (556 MPa) and large uniform elongation (45%) was achieved in the investigated alloy. The enhancement of the strength is attributed to the combined effects of grain refinement, precipitation strengthening and microstructural heterogeneity. Our work demonstrated that the heterogeneity design could be realized by thermomechanical processes, which provided a practical strategy for producing HEAs with high performance.
      PubDate: 2021-11-01
       
  • Investigation and Modeling of Austenite Grain Evolution for a Typical
           High-strength Low-alloy Steel during Soaking and Deformation Process

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      Abstract: The final mechanical properties of components greatly depend on their grain size. It is necessary to study the grain evolution during different thermomechanical processes. In the study, the real-time austenite grain evolution of a high-strength low-alloy (HSLA) steel during the soaking process is investigated by in situ experiments. The effects of different deformation parameters on the dynamic recrystallization (DRX) kinetic behaviors are investigated by hot compression experiments. Based on the observations and statistics of the microstructures at different thermomechanical processes, a unified grain size model is established to evaluate the effects of soaking parameters and deformation parameters on the austenite grain evolution. Also, the DRX kinetic model and critical strain model are established, which can describe the effects of the soaking process on the DRX kinetics process well. The established grain size model and DRX kinetic model are compiled into the numerical simulation software using Fortran language. The austenite grain evolution of the material under different deformation conditions is simulated, which is consistent with the experimental results. It indicates that the established model is reliable, and can be used to simulate and predict the grain size during different thermomechanical processes accurately.
      PubDate: 2021-10-23
       
  • Effect of Vacuum Pressure on the Initiation and Propagation of Pitting
           Corrosion of 2205 Duplex Stainless Steel in Concentrated Seawater

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      Abstract: Pitting initiation and stable propagation behaviors of 2205 duplex stainless steel were investigated in the hot concentrated seawater under vacuum pressures by potentiostatic polarization. Both applied potentials and vacuum pressures greatly influence the pitting corrosion. Higher potentials lead to much faster stable pitting initiation and growth rates in both static (101.3 kPa) and dynamic (28.4 kPa) solutions. The pressure reduction can also accelerate the pitting initiation rate. However, the boiling of solution can influence the pitting propagation mechanism. The dynamic actions of boiling bubbles are unfavorable to the pit propagation and result in the formation of relatively smooth pit bottom without secondary pits.
      PubDate: 2021-10-22
       
  • Influence of Sc Addition on Precipitation Behavior and Properties of
           Al-Cu-Mg Alloy

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      Abstract: In this study, the Al-5.10Cu-0.65 Mg alloys without and with 0.2 wt% Sc addition were prepared to unveil the effect of Sc on the precipitate behavior and properties by atomic-scale scanning transmission electron microscopy. The results show that addition of Sc is able to significantly suppress the formation of the peak-hardening θ' and S precipitates but in favor of stabilizing Guinier–Preston–Bagaryatsky (GPB) zones during isothermal aging at 180 °C. The generation of unique GPB precursors dictating the evolution of the subsequent peak-hardening GPB zones is highly correlated with the insufficient vacancies and dragging effect of Sc to Cu in the Al-Cu-Mg-Sc alloy, thereby restricting the nucleation of θ′ and S precipitates owing to the decreased available Cu solutes. In property, 0.2 wt% Sc addition can not only enhance the corrosion resistance but also the electrical conductivity of the peak-hardening alloy. In addition, the peak-hardening Al-Cu-Mg-Sc alloy is also featured with increased strength without losing the ductility compared to its solid solution state. Further analyses indicate that the improved properties are essentially attributed to the formation of densely distributed strain-free GPB zones and smaller precipitate-free zones. The obtained results could provide a potential design strategy of high-performance alloys by Sc addition.
      PubDate: 2021-10-20
       
  • Phase Evolution and Thermal Expansion Behavior of a γ′ Precipitated
           Ni-Based Superalloy by Synchrotron X-Ray Diffraction

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      Abstract: The phase evolution and thermal expansion behavior in superalloy during heating play an essential role in controlling the size and distribution of precipitates, as well as optimizing thermomechanical properties. Synchrotron X-ray diffraction is able to go through the interior of sample and can be carried out with in situ environment, and thus, it can obtain more statistics information in real time comparing with traditional methods, such as electron and optical microscopies. In this study, in situ heating synchrotron X-ray diffraction was carried out to study the phase evolution in a typical γ′ phase precipitation strengthened Ni-based superalloy, Waspaloy, from 29 to 1050 °C. The γ′, γ, M23C6 and MC phases, including their lattice parameters, misfits, dissolution behavior and thermal expansion coefficients, were mainly investigated. The γ′ phase and M23C6 carbides appeared obvious dissolution during heating and re-precipitated when the temperature dropped to room temperature. Combining with the microscopy results, we can indicate that the dissolution of M23C6 leads to the growth of grain and γ′ phase cannot be completely dissolved for the short holding time above the solution temperature. Besides, the coefficients of thermal expansions of all the phases are calculated and fitted as polynomials.
      PubDate: 2021-10-15
       
  • Nature of CoCrFeMnNi/Fe and CoCrFeMnNi/Al Solid/Solid Interface

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      Abstract: To shed light into the application potential of high-entropy alloys as “interlayer” materials for Al-steel solid-state joining, we investigated the nature of the CoCrFeMnNi/Fe and CoCrFeMnNi/Al solid/solid interfaces, focusing on the bonding behavior and phase components. Good metallurgical bonding without the formation of hard and brittle IMC can be achieved for CoCrFeMnNi/Fe solid/solid interface. In contrast to the formation of Al5Fe2 phase at the Fe/Al interface, Al13Fe4-type IMC, in which the Fe site is co-occupied equally by Co, Cr, Fe, Mn and Ni, dominates the CoCrFeMnNi/Al interface. Although the formation of IMC at the CoCrFeMnNi/Al interface is not avoidable, the thickness and hardness of the Al13(CoCrFeMnNi)4 phase formed at the CoCrFeMnNi/Al interface are significantly lower than the Al5Fe2 phase formed at the Fe/Al interface. The activation energies for the interdiffusion of Fe/Al and CoCrFeMnNi/Al static diffusion couple are 341.6 kJ/mol and 329.5 kJ/mol, respectively. Despite this similarity, under identical static annealing condition, the interdiffusion coefficient of the CoCrFeMnNi/Al diffusion couple is significantly lower than that of the Fe/Al diffusion couple. This is thus mainly a result of the reduced atomic mobility/diffusivity caused by the compositional complexity in CoCrFeMnNi high-entropy alloy.
      PubDate: 2021-10-10
       
  • Application of Synchrotron X-Ray Imaging and Diffraction in Additive
           Manufacturing: A Review

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      Abstract: Additive manufacturing (AM) is a rapid prototyping technology based on the idea of discrete accumulation which offers an advantage of economically fabricating a component with complex geometries in a rapid design-to-manufacture cycle. However, various internal defects, such as balling, cracks, residual stress and porosity, are inevitably occurred during AM due to the complexity of laser/electron beam-powder interaction, rapid melting and solidification process, and microstructure evolution. The existence of porosity defects can potentially deteriorate the mechanical properties of selective laser melting (SLM) components, such as material stiffness, hardness, tensile strength, and fatigue resistance performance. Synchrotron X-ray imaging and diffraction are important non-destructive means to elaborately characterize the internal defect characteristics and mechanical properties of AM parts. This paper presents a review on the application of synchrotron X-ray in identifying and verifying the quality and requirement of AM parts. Defects, microstructures and mechanical properties of printed components characterized by synchrotron X-ray imaging and diffraction are summarized in this review. Subsequently, this paper also elaborates on the online characterization of the evolution of the microstructure during AM using synchrotron X-ray imaging, and introduces the method for measuring AM stress by X-ray diffraction (XRD). Finally, the future application of synchrotron X-ray characterization in the AM is prospected.
      PubDate: 2021-10-09
       
  • Unveiling the Growth Mechanism of Faceted Primary Al2Cu with Complex
           Morphologies During Solidification

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      Abstract: The growth characteristic of primary faceted Al2Cu intermetallic compounds (IMCs) during solidification was observed directly by synchrotron radiography. The formation and transition mechanisms of Al2Cu IMCs with diverse morphologies were elucidated by first-principle calculations combined with electron backscatter diffraction analysis. The Al2Cu crystals preferred to grow along the [001] direction and were bounded by {110} planes with the lowest surface energy. The faceted Al2Cu rod-like clusters consisted of multiple crystals with complete rod, hollowness and partial sides, which was attributed to the increase in strain energy and solute redistribution during solidification. The faceted Al2Cu with branches was characteristic with the perpendicular relationship between the main branches and side steps and partial coalescence at the junction, which was ascribed to the continuous propagation and growth of newly formed crystals along the diagonal direction.
      PubDate: 2021-10-08
       
 
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