Subjects -> MATHEMATICS (Total: 1118 journals)
    - APPLIED MATHEMATICS (92 journals)
    - GEOMETRY AND TOPOLOGY (23 journals)
    - MATHEMATICS (819 journals)
    - MATHEMATICS (GENERAL) (45 journals)
    - NUMERICAL ANALYSIS (26 journals)
    - PROBABILITIES AND MATH STATISTICS (113 journals)

MATHEMATICS (819 journals)            First | 1 2 3 4 5     

Showing 401 - 538 of 538 Journals sorted alphabetically
Journal of Geological Research     Open Access   (Followers: 1)
Journal of Geovisualization and Spatial Analysis     Hybrid Journal  
Journal of Global Optimization     Hybrid Journal   (Followers: 7)
Journal of Global Research in Mathematical Archives     Open Access   (Followers: 1)
Journal of Homotopy and Related Structures     Hybrid Journal  
Journal of Honai Math     Open Access  
Journal of Humanistic Mathematics     Open Access   (Followers: 1)
Journal of Hyperbolic Differential Equations     Hybrid Journal  
Journal of Indian Council of Philosophical Research     Hybrid Journal  
Journal of Industrial Mathematics     Open Access   (Followers: 2)
Journal of Inequalities and Applications     Open Access  
Journal of Infrared, Millimeter and Terahertz Waves     Hybrid Journal   (Followers: 3)
Journal of Integrable Systems     Open Access   (Followers: 1)
Journal of K-Theory     Full-text available via subscription  
Journal of Knot Theory and Its Ramifications     Hybrid Journal   (Followers: 2)
Journal of Liquid Chromatography & Related Technologies     Hybrid Journal   (Followers: 7)
Journal of Logical and Algebraic Methods in Programming     Hybrid Journal   (Followers: 1)
Journal of Manufacturing Systems     Full-text available via subscription   (Followers: 4)
Journal of Mathematical Analysis and Applications     Full-text available via subscription   (Followers: 5)
Journal of mathematical and computational science     Open Access   (Followers: 7)
Journal of Mathematical and Fundamental Sciences     Open Access  
Journal of Mathematical Behavior     Hybrid Journal   (Followers: 4)
Journal of Mathematical Chemistry     Hybrid Journal   (Followers: 5)
Journal of Mathematical Extension     Open Access   (Followers: 3)
Journal of Mathematical Finance     Open Access   (Followers: 9)
Journal of Mathematical Imaging and Vision     Hybrid Journal   (Followers: 7)
Journal of Mathematical Logic     Hybrid Journal   (Followers: 3)
Journal of Mathematical Modelling and Algorithms     Hybrid Journal   (Followers: 1)
Journal of Mathematical Neuroscience     Open Access   (Followers: 10)
Journal of Mathematical Sciences     Hybrid Journal   (Followers: 1)
Journal of Mathematical Sciences and Applications     Open Access   (Followers: 4)
Journal of Mathematical Sociology     Hybrid Journal   (Followers: 3)
Journal of Mathematics     Open Access  
Journal of Mathematics and Statistics     Open Access   (Followers: 8)
Journal of Mathematics and Statistics Studies     Open Access   (Followers: 3)
Journal of Mathematics and the Arts     Hybrid Journal   (Followers: 2)
Journal of Mathematics Education at Teachers College     Open Access   (Followers: 4)
Journal of Mathematics in Industry     Open Access  
Journal of Mathematics Research     Open Access   (Followers: 6)
Journal of Metallurgy     Open Access   (Followers: 8)
Journal of Modern Mathematics Frontier     Open Access  
Journal of Multidisciplinary Modeling and Optimization     Open Access   (Followers: 1)
Journal of Multivariate Analysis     Hybrid Journal   (Followers: 13)
Journal of Natural Sciences and Mathematics Research     Open Access  
Journal of Nonlinear Analysis and Optimization : Theory & Applications     Open Access   (Followers: 4)
Journal of Nonlinear Mathematical Physics     Hybrid Journal   (Followers: 3)
Journal of Nonlinear Science     Hybrid Journal   (Followers: 1)
Journal of Numerical Cognition     Open Access   (Followers: 1)
Journal of Optimization     Open Access   (Followers: 5)
Journal of Peridynamics and Nonlocal Modeling     Hybrid Journal  
Journal of Problem Solving     Open Access   (Followers: 2)
Journal of Progressive Research in Mathematics     Open Access   (Followers: 5)
Journal of Pseudo-Differential Operators and Applications     Hybrid Journal  
Journal of Pure and Applied Algebra     Full-text available via subscription   (Followers: 4)
Journal of Quantitative Linguistics     Hybrid Journal   (Followers: 6)
Journal of Scientific Computing     Hybrid Journal   (Followers: 19)
Journal of Scientific Research     Open Access  
Journal of Symbolic Computation     Hybrid Journal   (Followers: 2)
Journal of the Australian Mathematical Society     Full-text available via subscription  
Journal of the Egyptian Mathematical Society     Open Access  
Journal of the European Mathematical Society     Full-text available via subscription   (Followers: 2)
Journal of the Indian Mathematical Society     Hybrid Journal   (Followers: 1)
Journal of the Institute of Mathematics of Jussieu     Hybrid Journal  
Journal of the London Mathematical Society     Hybrid Journal   (Followers: 3)
Journal of the Nigerian Mathematical Society     Open Access   (Followers: 1)
Journal of Theoretical and Applied Physics     Open Access   (Followers: 9)
Journal of Topology and Analysis     Hybrid Journal  
Journal of Transport and Supply Chain Management     Open Access   (Followers: 16)
Journal of Turbulence     Hybrid Journal   (Followers: 10)
Journal of Uncertainty Analysis and Applications     Open Access   (Followers: 1)
Journal of Universal Mathematics     Open Access  
Journal of Urban Regeneration & Renewal     Full-text available via subscription   (Followers: 11)
JRAMathEdu : Journal of Research and Advances in Mathematics Education     Open Access   (Followers: 7)
JUMLAHKU : Jurnal Matematika Ilmiah STKIP Muhammadiyah Kuningan     Open Access   (Followers: 2)
JURING (Journal for Research in Mathematics Learning)     Open Access   (Followers: 1)
Jurnal Ilmiah AdMathEdu     Open Access  
Jurnal Matematika     Open Access   (Followers: 1)
Jurnal Matematika Integratif     Open Access  
Jurnal Matematika, Sains, Dan Teknologi     Open Access  
Jurnal Natural     Open Access  
Jurnal Pendidikan Matematika Raflesia     Open Access  
Jurnal Penelitian Pembelajaran Matematika Sekolah     Open Access  
Jurnal Penelitian Sains (JPS)     Open Access  
Jurnal Riset Pendidikan Matematika     Open Access  
Jurnal Sains Matematika dan Statistika     Open Access  
Jurnal Tadris Matematika     Open Access  
Jurnal Teknologi dan Sistem Komputer     Open Access  
Kontinu : Jurnal Penelitian Didaktik Matematika     Open Access   (Followers: 2)
Kreano, Jurnal Matematika Kreatif-Inovatif     Open Access   (Followers: 6)
Le Matematiche     Open Access  
Lettera Matematica     Hybrid Journal  
Lietuvos Matematikos Rinkinys     Open Access   (Followers: 3)
Limits : Journal of Mathematics and Its Applications     Open Access   (Followers: 1)
Linear Algebra and its Applications     Full-text available via subscription   (Followers: 24)
Linear and Multilinear Algebra     Hybrid Journal   (Followers: 8)
Lithuanian Mathematical Journal     Hybrid Journal  
LMS Journal of Computation and Mathematics     Free  
Lobachevskii Journal of Mathematics     Open Access  
Logic and Analysis     Hybrid Journal   (Followers: 1)
Logic Journal of the IGPL     Hybrid Journal   (Followers: 1)
Logica Universalis     Hybrid Journal  
manuscripta mathematica     Hybrid Journal  
MaPan : Jurnal Matematika dan Pembelajaran     Open Access  
Marine Genomics     Hybrid Journal   (Followers: 2)
Matemáticas, Educación y Sociedad     Open Access  
Matematicheskie Zametki     Full-text available via subscription  
Mathematica Eterna     Open Access  
Mathematica Scandinavica     Full-text available via subscription   (Followers: 1)
Mathematical Analysis and its Contemporary Applications     Open Access  
Mathematical and Computational Forestry & Natural-Resource Sciences     Free  
Mathematical Communications     Open Access  
Mathematical Computation     Open Access   (Followers: 1)
Mathematical Geosciences     Hybrid Journal   (Followers: 4)
Mathematical Journal of Interdisciplinary Sciences     Open Access   (Followers: 1)
Mathematical Medicine and Biology: A Journal of the IMA     Hybrid Journal   (Followers: 2)
Mathematical Methods in the Applied Sciences     Hybrid Journal   (Followers: 5)
Mathematical Methods of Statistics     Hybrid Journal   (Followers: 4)
Mathematical Modelling and Analysis     Open Access   (Followers: 1)
Mathematical Modelling of Natural Phenomena     Open Access   (Followers: 2)
Mathematical Models and Methods in Applied Sciences     Hybrid Journal   (Followers: 2)
Mathematical Models in Engineering     Open Access  
Mathematical Notes     Hybrid Journal  
Mathematical Proceedings of the Cambridge Philosophical Society     Full-text available via subscription   (Followers: 2)
Mathematical Programming Computation     Hybrid Journal   (Followers: 3)
Mathematical Sciences     Open Access  
Mathematical Social Sciences     Hybrid Journal   (Followers: 1)
Mathematical Theory and Modeling     Open Access   (Followers: 13)
Mathematical Thinking and Learning     Hybrid Journal   (Followers: 4)
Mathematics and Statistics     Open Access   (Followers: 5)
Mathematics Education Forum Chitwan     Open Access   (Followers: 2)
Mathematics Education Journal     Open Access   (Followers: 3)
Mathematics Education Research Journal     Partially Free   (Followers: 20)
Mathematics in Science and Engineering     Full-text available via subscription  
Mathematics of Control, Signals, and Systems (MCSS)     Hybrid Journal   (Followers: 5)
Mathématiques et sciences humaines     Open Access   (Followers: 6)
Mathematische Annalen     Hybrid Journal   (Followers: 1)
Mathematische Nachrichten     Hybrid Journal   (Followers: 1)
Mathematische Semesterberichte     Hybrid Journal  
Mathematische Zeitschrift     Hybrid Journal   (Followers: 1)
MathLAB Journal     Open Access   (Followers: 4)
MATICS     Open Access   (Followers: 2)
Matrix Science Mathematic     Open Access   (Followers: 1)
Measurement Science Review     Open Access   (Followers: 3)
Mediterranean Journal of Mathematics     Hybrid Journal  
Memetic Computing     Hybrid Journal  
Mendel : Soft Computing Journal     Open Access  
Metaheuristics     Hybrid Journal  
Metals and Materials International     Hybrid Journal  
Metascience     Hybrid Journal   (Followers: 1)
Metrology and Instruments / Метрологія та прилади     Open Access   (Followers: 1)
Milan Journal of Mathematics     Hybrid Journal  
MLQ- Mathematical Logic Quarterly     Hybrid Journal   (Followers: 1)
Modelling in Civil and Environmental Engineering     Open Access   (Followers: 5)
MONA : Matematik- og Naturfagsdidaktik     Hybrid Journal   (Followers: 4)
Monatshefte fur Mathematik     Hybrid Journal  
Moroccan Journal of Pure and Applied Analysis     Open Access   (Followers: 4)
Moscow University Mathematics Bulletin     Hybrid Journal  
MSOR Connections     Open Access   (Followers: 1)
Multiscale Modeling and Simulation     Hybrid Journal   (Followers: 4)
MUST : Journal of Mathematics Education, Science and Technology     Open Access   (Followers: 4)
Nagoya Mathematical Journal     Hybrid Journal  
Nano Research     Hybrid Journal   (Followers: 4)
Nanotechnologies in Russia     Hybrid Journal   (Followers: 1)
Natural Resource Modeling     Hybrid Journal   (Followers: 1)
New Mathematics and Natural Computation     Hybrid Journal   (Followers: 1)
Nonlinear Analysis : Modelling and Control     Open Access   (Followers: 1)
Nonlinear Analysis : Theory, Methods & Applications     Hybrid Journal   (Followers: 1)
Nonlinear Analysis: Hybrid Systems     Hybrid Journal  
Nonlinear Analysis: Real World Applications     Hybrid Journal   (Followers: 2)
Nonlinear Differential Equations and Applications NoDEA     Hybrid Journal  
Nonlinear Oscillations     Hybrid Journal   (Followers: 1)
North Carolina Journal of Mathematics and Statistics     Open Access  
North-Holland Mathematical Library     Full-text available via subscription   (Followers: 1)
North-Holland Mathematics Studies     Full-text available via subscription  
North-Holland Series in Applied Mathematics and Mechanics     Full-text available via subscription   (Followers: 1)
Note di Matematica     Open Access  
NTM Zeitschrift für Geschichte der Wissenschaften, Technik und Medizin     Hybrid Journal   (Followers: 4)
Numeracy : Advancing Education in Quantitative Literacy     Open Access  
Numerical Analysis and Applications     Hybrid Journal   (Followers: 1)
Numerical Functional Analysis and Optimization     Hybrid Journal   (Followers: 2)
Numerical Linear Algebra with Applications     Hybrid Journal   (Followers: 8)
Numerical Mathematics : Theory, Methods and Applications     Full-text available via subscription  
Numerische Mathematik     Hybrid Journal  
Open Journal of Discrete Mathematics     Open Access   (Followers: 6)
Open Journal of Modelling and Simulation     Open Access   (Followers: 2)
Operations Research Letters     Hybrid Journal   (Followers: 11)
Optimization Letters     Hybrid Journal   (Followers: 2)
Optimization Methods and Software     Hybrid Journal   (Followers: 8)
Opuscula Mathematica     Open Access   (Followers: 109)
Order     Hybrid Journal   (Followers: 1)
ORiON     Open Access  
P-Adic Numbers, Ultrametric Analysis, and Applications     Hybrid Journal  
PAMM : Proceedings in Applied Mathematics and Mechanics     Free   (Followers: 1)
Parallel Processing Letters     Hybrid Journal   (Followers: 3)
Peking Mathematical Journal     Hybrid Journal  
Periodica Mathematica Hungarica     Full-text available via subscription   (Followers: 1)
Perspectivas da Educação Matemática     Open Access  
Petroleum Science     Open Access   (Followers: 1)
Philosophia Mathematica     Hybrid Journal   (Followers: 1)
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences     Full-text available via subscription   (Followers: 10)

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Similar Journals
Journal Cover
Metals and Materials International
Journal Prestige (SJR): 0.724
Citation Impact (citeScore): 2
Number of Followers: 0  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1598-9623 - ISSN (Online) 2005-4149
Published by Springer-Verlag Homepage  [2658 journals]
  • Distribution of Bi–MnS Inclusions Existing in 1215MS Steels: Correlation
           with Thermal Physical Coefficient

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      Abstract: This work aims to comprehensively summarize the types and distribution of the isolated Bi particles and MnS inclusions in the Bi-bearing steels, to study the precipitated behavior of sulfide, and to study the effect of Bi particles on grain sizes and the volume thermal expansion coefficients of the steels. Results show that the average percentage of the isolated Bi particles, semi-encapsulation, complete encapsulation, back-bridge, tiny encapsulation, cavity bridge Bi–MnS inclusions in the Bi-bearing steels was 16.89%, 20.49%, 3.44%, 16.89%, 31.63%, 10.66%, respectively. The average equivalent diameters of the grains in the 0 ppm, 130 ppm, 240 ppm, 760 ppm, 1200 ppm and 2300 ppm Bi content steels were 20.88, 20.17, 19.54, 18.13, 13.98 and 13.25 μm, respectively. The precipitated equilibrium mass concentration product of the MnS (w[Mn]·w[S]) was calculated to be 1.07, and the solid fraction fS value was 0.61. At 950 °C, the volume thermal expansion coefficient change (ΔVE) in 760 ppm Bi content steel was minimum 4 × 10–10%, while at 461.6 °C the ΔVE was maximum, 0.09%, which means that Bi affected the volume thermal expansion of the steel strongest in this temperature range. Graphic
      PubDate: 2021-10-09
       
  • Study of the Effect of Two Separate Tilt Angles of Laser Scanning Lines on
           the Microstructure and Mechanical Properties in Direct Metal Laser
           Sintered AlSi10Mg Alloy

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      Abstract: The scanning strategy has a measurable impact on the grain size and growth direction of the produced parts in powder bed fusion. Tilting of the laser scan lines by 67° is a default procedure applicable to PBF machines for obtaining maximum variability in the direction of melt pools. In this work, AlSi10Mg parts were produced through direct metal laser sintering with two different scanning strategies. In the first strategy, the scanning lines were not tilted in between layers while in the second strategy, the scanning lines were tilted by 67°. The microstructures of the as-deposited alloys for the two strategies were evaluated by state-of-art characterization methods like scanning electron microscopy, electron backscatter diffraction (EBSD), X-ray computed tomography (X-ray CT), and X-ray diffraction. Monotonic tensile tests were hence conducted in both categories. Greater tensile strength was demonstrated by the specimens with no tilting of the scan lines while the specimens produced with a 67° tilt manifested greater elongation. Grain morphology characterized by EBSD studies suggested an inhomogeneity in grain size for the specimens with no tilting of the scan lines. This had primarily attributed to the early failure of the same. It was also found out that the preferred growth direction of grains in AlSi10Mg was hindered by tilting the scan lines by 67°. X-Ray CT studies and Kocks–Mecking Analysis explained the deformation and hardening behavior of both the types in the view of porosity and structural defects. Graphical abstract
      PubDate: 2021-10-09
       
  • Effect of Electrochemical Hydrogen Charging Time on Hydrogen Embrittlement
           of the Hot-Rolled and Accelerated Cooling Treated API X70 Steel

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      Abstract: This study investigated the effect of the hydrogen charging time on the hydrogen embrittlement of hot-rolled and accelerated-cooling treated API X70 steel by using the electrochemical hydrogen charging method. Tensile and V-notch Charpy impact test were completed for the specimens of hydrogen charged for 0, 2, 4, and 10 h, and then microstructural observation were performed. The tensile and yield strength tended to decrease slightly and the total elongation started to decrease rapidly up to 2 h charging time and then these gradually decreased with the hydrogen charging time. The post-uniform elongation increased slightly after the holding time of 2 h due to the occurrence of two-step stress reduction phenomenon and its mechanism has suggested. The effect of the hydrogen embrittlement on impact absorption energy according to the hydrogen charging time were also investigated. The fracture surface of the hydrogen charged ones are generally composed of cleavage fracture surfaces. It was demonstrated that the external cracks were formed on the outside of tensile tested specimen and the external shape of the fracture portion was fractured without large elongation at hydrogen charged specimens. Graphic
      PubDate: 2021-10-08
       
  • Application of an Image-Based Model of the Elastic Modulus of Porous
           Thermal Barrier Coatings

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      Abstract: The elastic modulus of plasma-sprayed thermal barrier coatings (TBCs), which have been utilized for gas turbine engine components at elevated temperatures, has been investigated using a proposed model. The main purpose of this paper is to explore the alterations in porous TBC microstructure that lead to alterations in its mechanical properties, including elastic modulus. This paper investigates the effect of different types of defects, i.e., nonflat porosity, microcracks and interlamellar porosity, on the elastic modulus of porous TBC materials. The first part of this paper quantitively studies the microstructural characterization of plasma-sprayed TBCs by means of an image analysis approach. The second part of this paper predicts the elastic modulus of plasma-sprayed TBCs based on microstructural changes, i.e., defects. The volumetric fraction of different types of defects and their shapes and orientations are also taken into account. It is found that both microcracks and interlamellar porosity exhibit a crucial optimization on the elastic modulus of porous TBCs, while nonflat porosity shows a lesser effect on the elastic modulus. The predicted data of the proposed model show relatively good agreement with FEA model results and experimentally measured results. These simulation results could help to further the understanding of the impact of porous TBC microstructural alterations on elastic modulus. Graphic abstract
      PubDate: 2021-10-07
       
  • Selective Laser Melting Process for Sensor Embedding into SUS316L with
           Heat Dissipative Inner Cavity Design

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      Abstract: Artificial intelligence and Internet of Things (IoT) technology, which are the core of the 4th industrial revolution, can resolve many problems that optimization of production times in the manufacturing process and reduction of materials required etc. In order to utilize the 4th industrial revolution technology, real-time monitoring technology of metal parts is essential, so technology for embedding sensors and IC chips into parts is essential. Using metal 3d printing technology, it is possible to embed IC chips into metal parts, which was impossible because of the existing high-temperature metal manufacturing process of casting or forging. Here we introduce a novel new method for sensor embedding into SUS316L by hemisphere design to avoid direct laser exposure onto sensors during selective laser melting process. Thermal and microstructural analysis was carried out to characterize the property of inner hemisphere for safe thermal couple embedding into SUS316L. Graphical
      PubDate: 2021-10-05
       
  • Strontium in Al–Si–Mg Alloy: A Review

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      Abstract: The present article reviews the development of cast aluminium alloy with highlights on improvement in the morphological, mechanical, tribological, and ageing properties of Sr modified Al–Si and Al–Si–Mg alloys. Aluminium and its alloys find application in the automobile and aviation industries. The main objective of utilizing aluminium alloys for structural application, manufacturing of pistons and engine block for automobile industries is its lightweight and low density. However, the low hardness of these alloys results in a high wear rate. The main factor that affects the properties of aluminium alloys is its microstructure, morphological behaviour, size of the grain and phase distribution. The morphological modification for these alloys is done through different processing techniques like casting, heat treatment, solutionising, and alloying element addition which augments the mechanical, corrosion, and tribological behaviour of these alloys. Of the alloying element additions Sr has proved to a very effective modifier for the alloy, and hence the method of modification was studied in detail. The unwanted effects especially porosity, being one of the main factors for failure of components, were investigated and methods to reduce it according to many researchers were included. Reinforcing the aluminium matrix with ceramic particles and surface modification also enhances the properties of aluminium alloys. The current article reviews the recent techniques to augment the microstructure, value of hardness, tensile properties, tribological properties, and corrosion behaviour of cast Al–Si and Al–Si–Mg alloys by the addition of strontium. Moreover, this review also focuses on the future scope of these aluminium alloys for structural application in automobile and lightweight industries. Graphic
      PubDate: 2021-10-05
       
  • Effect of Annealing and Crack Orientation on Fatigue Crack Propagation of
           Ti64 Alloy Fabricated by Direct Energy Deposition Process

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      Abstract: Effects of annealing condition and crack orientation on fatigue crack propagation (FCP) behavior of DED (direct energy deposition)-processed Ti–6Al–4V (Ti64) specimens were studied. It was found that the FCP resistance of Ti64 increased significantly with annealing, particularly above β transus temperature, due to the microstructural coarsening inducing less damage accumulation at the tip of crack. The FCP behavior of as-built and as-annealed DED Ti64 specimens was isotropic with crack direction either parallel or perpendicular to building direction. The detailed micrographic and fractographic analyses on FCP-tested specimens suggested that the presence of largely elongated β grain boundaries did not affect the advance of crack. Graphic
      PubDate: 2021-10-04
       
  • Computational Modelling and Experimental Analysis of Hardness and
           Microstructure of Reinforcing Bars Produced by Tempcore Process

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      Abstract: The reinforcing bar (rebar) produced by Tempcore process had tempered martensite structure on its surface, owing to quenching and tempering, and ferrite–pearlite structure at the core owing to slow cooling rate. Bainite, a low-temperature transformation phase, was observed in the transition area. Mechanical properties of the rebar are significantly influenced by area ratio and hardness of the tempered martensite. In this study, microstructure and area ratio of the tempered martensite of the rebar produced by the Tempcore process were predicted using finite volume method and a continuous cooling transformation diagram. The area ratio of the tempered martensite was predicted with error range of ± 6%. Furthermore, association between the microstructure and hardness was determined by a non-isothermal tempering experiment. The hardness of the tempered martensite was successfully predicted using the tempering temperature with R-squared 98%. The proposed methodology can be effectively used to control the mechanical properties of the rebars. Graphic
      PubDate: 2021-10-02
       
  • Tensile and High-Cycle Fatigue Properties of Extruded AZ91–0.3Ca–0.2Y
           Alloy with Excellent Corrosion and Ignition Resistances

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      Abstract: Mg–Al–Zn–Ca–Y (SEN) alloys have been recently developed by adding small amounts of Ca and Y to commercial Mg–Al–Zn (AZ series) alloys. These alloys possess superior corrosion and ignition resistances to their commercial AZ series counterparts. Here, commercial AZ91 (Mg–9Al–0.8Zn, wt%) and developed SEN9 (Mg–9Al–0.8Zn–0.3Ca–0.2Y, wt%) alloys are extruded under the same conditions, and the microstructure, tensile properties, and high-cycle fatigue properties of the extruded alloys are compared. The extruded SEN9 alloy has a smaller average grain size and higher microstructural homogeneity than the extruded AZ91 alloy because the Al2Y, Al2Ca, and Al8Mn4Y particles in the homogenized SEN9 billet promote dynamic recrystallization during extrusion. Despite their different microstructures, the two alloys possess similar tensile strengths because the strong precipitation hardening in the extruded AZ91 alloy is offset by strong grain-boundary hardening in the extruded SEN9 alloy. However, the extruded SEN9 alloy exhibits higher tensile elongation because deformation twinning is suppressed by the finer grains. The fatigue strength of the extruded SEN9 alloy (100 MPa) is slightly lower than that of the extruded AZ91 alloy (110 MPa). For the extruded AZ91 alloy, fatigue cracks initiate on the surface in all specimens, whereas for the extruded SEN9 alloy, fatigue cracks initiate in an Al2Ca or Al2Y particle present on the subsurface in some specimens, especially at low stress amplitudes. The Al2Ca and Al2Y particles are larger than the Mg17Al12 precipitates, and considerably harder than the matrix. Consequently, local stress is highly concentrated in these particles during cyclic loading, which eventually causes premature fatigue cracking and decreased fatigue resistance. Graphic abstract
      PubDate: 2021-10-02
       
  • High Performance Cu Matrix Nanocomposite Fabricated Through Spark Plasma
           Sintering of Cu and Cu-Coated CNT

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      Abstract: In this paper, the effects of Cu coating of carbon nanotube (CNTs) as reinforcement on structural, microstructural, physical and mechanical properties of Cu–3 wt%CNT nanocomposite were investigated. CNTs were coated by Cu using the electroless technique for 1 and 2 h. Bulk nanocomposite samples were produced by spark plasma sintering of a mechanically milled powder mixture of Cu and CNT. Kinetic study showed a nucleation and growth mechanism for the Cu coating process. Microstructural characterization showed that the coated CNTs dispersed more homogeneously in the powder mixture. Results also revealed that 1 h coating of CNTs led to the higher relative density and thermal properties. The coating process increased 62 Brinell hardness (BHN) in hardness, 14% IACS in electrical conductivity for Cu–CNT nanocomposite. Transmission electron microscopy analysis showed a strong bonding between CNT and Cu matrix within the distinguishable interface. About 20 MPa increase in shear strength of nanocomposite was observed by 1 h coating of CNTs. Also, the fracture surfaces exhibit changes in the mode of fracture by well-bonded CNTs with the Cu matrix. The coefficient of thermal expansion and thermal distortion parameter revealed 12.7 ppm/k and 0.037 ppm.m/w for the sample including 1 h coated CNT, respectively. Graphic
      PubDate: 2021-10-01
       
  • Effect of Molybdate Conversion Coating of Magnesium Alloy Reinforced by
           Micro-arc Oxidation

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      Abstract: In order to enhance the corrosion resistance of molybdate conversion coating, the molybdate coating is subjected to micro-arc oxidation treatment in electrolyte with Na2SiO3 as a main salt. The electrochemical behavior and corrosion weight loss of different coating were studied. The surface morphology, element composition, roughness and phase composition of different coatings were analyzed by SEM, EDS, laser confocal microscopy and XRD, the growth process of different micro-arc oxidation coatings was explored. The results shows that the arcing voltage of the molybdate coating enhanced by micro-arc oxidation is significantly reduced, the corrosion potential is shifted to the right, and the corrosion weightlessloss of the coating is the lowest, compared with the molybdate coating and the micro-arc oxidation coating. Micro-arc oxidation on the surface of the molybdate coating is beneficial to the formation of MgAl2O4 and the production of new phase is MoSi2, which can better improve the corrosion resistance of the molybdate coating. The micro-arc oxide coating does not form a ceramic film with a pore structure at the moment of arcing. As the micro-arc oxidation time prolongs, the ceramic film is gradually formed. When the time reaches 60 s, the ceramic film is completely formed. Graphic In this paper, micro-arc oxidation treatment is performed on the basis of molybdate conversion coating to obtain micro-arc oxidation enhanced molybdate coating. The experiment is mainly divided into three parts: the first part, molybdate conversion treatment of the magnesium alloy substrate to obtain a molybdate conversion coating. The second part, the micro-arc oxidation treatment is performed on the surface of the molybdate coating, and discharge channels appear on the surface. The third part, micro-arc oxidation enhanced molybdate coating is obtained.
      PubDate: 2021-10-01
       
  • Evolution of Microstructure and Mechanical Properties of Graphitized
           Fe–0.55C–2.3Si Steel During Quenching and Tempering Treatment

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      Abstract: This study investigates the variations in the microstructure and mechanical properties of a medium-carbon high-Si steel (Fe–0.55C–2.3Si) during graphitization heat treatment and subsequent quenching and tempering heat treatment. The microstructure comprising ferrite and pearlite of the as-rolled sample changes to a more ductile microstructure with fine graphites uniformly dispersed in the ferrite matrix after graphitization treatment. These formed graphites are completely dissolved into the ferrite matrix after austenitizing treatment at 900 °C, but preexisting graphite positions remains as voids. The average size and number density of voids are nearly identical to those of the pre-existed graphites. The subsequent tempering treatments at 300 °C and 500 °C cause little changes in the size and number of the voids. Therefore, the formation of voids in the quenched-and-tempered samples is directly related to the graphites of the initial graphitized sample. The average size of graphites and voids is inversely proportional to the logarithm of their number density. When the as-rolled sample is completely graphitized, its ultimate tensile strength decreases from 928 to 494 MPa and its tensile elongation increases from 20.7 to 34.0%, indicating that the medium-carbon high-Si steel is substantially softened through graphitization treatment. Moreover, subsequent quenching and tempering treatment at 500 °C increases its ultimate tensile strength to 1168 MPa. The drastic softening through graphitization and significant strengthening through subsequent quenching and tempering exhibit the possibility of the application of medium-carbon, high-Si steels as cold heading quality steels for manufacturing fastener components. Graphic abstract
      PubDate: 2021-10-01
       
  • Aluminum ASA 6061 Anodizing Process by Chromic Acid Using Box–Wilson
           Central Composite Design: Optimization and Corrosion Tendency

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      Abstract: The behavior of anodic porous alumina film formed on an aluminum surface by anodizing in chromic acid solutions was optimized using Box–Wilson experimental design. The film thickness was correlated as a function of temperature, acid concentration, applied voltage, and time. A mathematical model was suggested and optimized. Results of coating thickness indicate that both temperature and time play an important role in the anodizing process. The interaction effect of variables on the film thickness is less pronounced compared with the effect of the main variables. Optimum film thickness obtained during the anodizing process was 10.43 µm at the optimum value of temperature (45 °C) and time (68 min). The polarization measurement of anodized aluminum ASA 6061 in chromic acid shows a high corrosion resistance in the presence of coating. The results confirmed by using surface morphology investigations. Graphic
      PubDate: 2021-10-01
       
  • Comparisons of Age Hardening and Precipitation Behavior in 7075 Alloy
           Under Single and Double-Stage Aging Treatments

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      Abstract: Various sets of heat treatments are applied on 7075 alloy in this study in order to reduce the treatment time and yet still achieve the similar mechanical property as the traditional T6 tempered alloy. The main parameters like solid solution treatment time, single aging temperature, as well as first aging duration in double aging treatment, first aging temperature and second aging temperature are studied and valued by hardness test. The double aging treatment at 125 °C for 60 min and then at 165 °C for 130 min is compared with traditional single aging treatment by using advanced Cs-corrected high-angle annular dark field scanning-transmission electron microscopy (HAADF-STEM). The precipitates and dispersoids found in those two corresponding samples are mainly Cr-containing large dispersoids, a few η particles and large quantity of fine precipitates like η′. The similarity of precipitates in them can well support the approximate hardness level of the double aged and single aged samples. Graphic
      PubDate: 2021-10-01
       
  • Effect of Lanthanum Addition on Grain Refinement and Mechanical Properties
           of Mg–9Li–3Al Alloy

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      Abstract: The impact of lanthanum addition on the microstructural changes and mechanical characteristics of Mg–9Li–3Al + xLa alloys are studied. The alloys are fabricated through a liquid metallurgy route involving stir casting by an electrical resistance furnace. The microstructural analysis showed that the as-cast alloys primarily comprises of α-Mg and β-Li phases. Irregular distribution of Al–Li lamellar and some granular fragments MgLi2Al observed over the magnesium-rich α-phase and lithium-rich β-phase. The influence of lanthanum addition to the alloy system leads to grain refinement by forming Al11La3 and Al4La intermetallics. Among the series of cast alloys, the Mg–9Li–3Al–1La alloy exhibits excellent ultimate tensile strength—178 MPa with 10.2% elongation. Addition of 1.5 wt% La and beyond tends to coarsen the grains leading to a reduction in mechanical strength. Hot extruded Mg–9Li–3Al–1La alloy exhibited more refinement in the microstructure and breakdown of intermetallic (Al4La and Al11La3) is observed. A significant improvement in the UTS values around 39% displayed by the Mg–9Li–3Al–1La alloy extruded at a ratio of 25:1. Graphic
      PubDate: 2021-10-01
       
  • Influence of Microstructure on Low-Cycle and Extremely-Low-Cycle Fatigue
           Resistance of Low-Carbon Steels

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      Abstract: The goals of this study were to quantify and explain the effects of microstructure on the resistance of low-carbon steels to low-cycle fatigue and to extremely low-cycle fatigue (ELCF). Three different microstructures (ferrite–pearlite, ferrite–martensite, and ferrite–bainite–martensite) were tested, and their fatigue properties were analyzed using the strain-based Coffin–Manson model and an energy-based model. According to the Coffin–Manson model, ferrite–pearlite showed the best ELCF resistance, whereas in the energy-based model that considers the effect of tensile strength ferrite–bainite–martensite revealed the highest ELCF resistance. At similar tensile strength, ferrite–bainite–martensite had longer ELCF life than ferrite–martensite; the difference may be a result of the smaller strain incompatibility between bainite and ferrite than between ferrite and martensite. In all three microstructures, cracks initiated at the surface and propagated into the interior; this result indicates that fracture mode was not altered during cyclic loading at high strain amplitudes. Ferrite–martensite microstructure developed many sub-cracks surrounding a main crack; they could facilitate propagation of a main crack, and thereby degrade fatigue life at high strain amplitudes. Graphic
      PubDate: 2021-10-01
       
  • Physical Vapor Deposition Assisted Diffusion Bonding of Al Alloy to Mg
           Alloy Using Silver Interlayer

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      Abstract: Two dissimilar alloys Al 5083 and Mg-AZ31 were diffusion bonded using two different interlayer applying methods, where the interlayer was 30 µm pure silver foil and 4 µm physical vapor deposited silver on Al and Mg substrates. The optimized variables used in diffusion bonding processes were holding time of 60 min and bonding temperature of 470 °C. The X-ray diffraction results confirmed the formation of Mg–Ag, Ag–Zn, and Ag–Al phases namely: MgAg, AgZn, Ag5Zn8, and Ag2Al instead of Al–Mg intermetallics at the interface. This proves the effective role of Ag, as a diffusion barrier and its success in minimizing the formation of harmful intermetallic phases at the interface. The joint with silver PVD coat, as interlayer, gave the higher shear strength of 31.6 MPa. Graphic
      PubDate: 2021-10-01
       
  • Effect of Microstructure on the Mechanical Properties and Fracture
           Toughness of API X65 Pipeline Steel in the Presence of Hydrogen

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      Abstract: This study investigated the influence of microstructure on the mechanical properties and fracture toughness of API X65 pipeline steel in the presence of hydrogen. In this study, electrochemical method was used for hydrogen charging and indentation technique was applied to obtain the fracture toughness. The results showed that in the presence of hydrogen, elongation (EL%), reduction of area (RA), ductile fracture percentage, and fracture toughness of all microstructures decreased. The microstructure of martensite (M) + bainite (B) + ferrite (F), had the highest hydrogen trapping and uptake (Capp) as 8.58 × 10–6 mol cm−3 and the lowest apparent hydrogen diffusivity (Dapp) as 5.68 × 10−10 m2 s−1; thus, the maximum decrements of 33% in fracture toughness, 40% in ductile fracture percentage, 47% in RA, and 35% in EL% were observed. However, the microstructure of ferrite (F) + degenerated perlite (DP) + martensite-austenite micro constituent (M/A), where the lowest value of 5.85 × 10–6 mol cm−3 for Capp and the highest value of 8.5 × 10–10 m2 s−1 for Dapp had the minimum decrements as 2% in fracture toughness, 10% in ductile fracture percentage, 4% in RA, and 7% in El%. According to the obtained results, depending on the type of microstructures, hydrogen-induced work softening or hardening were observed by decreasing or increasing the yield stress respectively. Graphic
      PubDate: 2021-10-01
       
  • Compressive Properties of A356 Closed-Cell Aluminum Foamed with a CaCO3
           Foaming Agent Without Stabilizer Particles

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      Abstract: The A356 aluminum alloy foams were fabricated by the melt foaming method using a CaCO3 foaming agent without any stabilizer particle. The samples of different densities ranging from 0.32 to 0.46 g/cm3 (relative densities of 0.12–0.17, respectively) and cell sizes ranging from 1.5 to 3.1 mm were formed. The effect of foaming conditions such as CaCO3 amount, mixing and holding time on compressive strength and energy absorption behavior were investigated. Results show that the compressive properties of the aluminum foam are characterized by three deformation stages: linear elastic stage, plastic collapse stage and densification stage. Also, the compressive stress and energy absorption capacity increase as the relative density increases. But elastic modulus of the foamed aluminum with 3 wt% CaCO3 (relative density = 14%) is higher than others because its cell size distribution is more homogeneous than others. The compressive strength of aluminum foams without any stabilizer particles is comparable to the other researches for aluminum foams with stabilizer particles at the same density. Graphic
      PubDate: 2021-10-01
       
  • Effects of Laser Power on the Microstructure Evolution and Mechanical
           Properties of Ti–6Al–4V Alloy Manufactured by Direct Energy Deposition
           

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      Abstract: Process optimization of additively manufactured Ti–6Al–4V alloy is an important aspect of the production of engineered, high-performance parts for the aerospace and medical industries. In this study, the microstructural evolution and mechanical properties of direct energy deposition processed Ti–6Al–4V alloy were investigated using different processing parameters. Experimental analyses revealed that the line energy density corresponding to the processing parameters of the direct energy deposition process influences the properties of additively manufactured Ti–6Al–4V alloy. First, an optimal line energy density limits the incidence and size of voids resulting from a lack of fusion to enhance both alloy strength and ductility. Second, an excessively high energy density induces the coarsening of prior-β grains to impair both alloy strength with the Hall–Petch relationship and alloy ductility due to the plastic deformation instability caused by the limited number of grains. These results indicate that both the extent of fusion and prior-β grain size affect the mechanical properties of additively manufactured Ti–6Al–4V alloy. Moreover, the results demonstrate the utility of the line energy density-based approach in determining the optimal processing parameters for realizing high-performance materials. Graphic abstract
      PubDate: 2021-10-01
       
 
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