Pub Date : 2021-09-02DOI: 10.1080/09500839.2021.1946187
R. Kalsar, R. Madhavan, S. Suwas
ABSTRACT An anomalous deformation texture evolution has been observed in high-stacking-fault-energy pure platinum during cold rolling. A maximum of 98% thickness reduction, equivalent to a true strain of 3.9, was imposed. The evolution of texture observed during rolling is characterised as sluggish and the starting texture was retained up to very large rolling strains. The evolution of a characteristic rolling texture and its strengthening was dramatic and observed only after 95% thickness reduction. The retarded evolution of texture in platinum is explained by the activity of an unusual non-octahedral slip system. To understand the contribution of non-octahedral slip systems towards texture evolution, visco-plastic self-consistent simulation was carried out. The simulation results show that the activation of {100}<011> non-octahedral slip system slows down the evolution of final texture. Detailed electron back-scatter diffraction microstructural analysis was carried out to understand the deformation mechanisms and its influence on delayed texture evolution.
{"title":"Texture evolution in platinum: the role of non-octahedral slip","authors":"R. Kalsar, R. Madhavan, S. Suwas","doi":"10.1080/09500839.2021.1946187","DOIUrl":"https://doi.org/10.1080/09500839.2021.1946187","url":null,"abstract":"ABSTRACT An anomalous deformation texture evolution has been observed in high-stacking-fault-energy pure platinum during cold rolling. A maximum of 98% thickness reduction, equivalent to a true strain of 3.9, was imposed. The evolution of texture observed during rolling is characterised as sluggish and the starting texture was retained up to very large rolling strains. The evolution of a characteristic rolling texture and its strengthening was dramatic and observed only after 95% thickness reduction. The retarded evolution of texture in platinum is explained by the activity of an unusual non-octahedral slip system. To understand the contribution of non-octahedral slip systems towards texture evolution, visco-plastic self-consistent simulation was carried out. The simulation results show that the activation of {100}<011> non-octahedral slip system slows down the evolution of final texture. Detailed electron back-scatter diffraction microstructural analysis was carried out to understand the deformation mechanisms and its influence on delayed texture evolution.","PeriodicalId":19860,"journal":{"name":"Philosophical Magazine Letters","volume":"101 1","pages":"360 - 369"},"PeriodicalIF":1.2,"publicationDate":"2021-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09500839.2021.1946187","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48685158","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-08-11DOI: 10.1080/09500839.2021.1962015
D. K. Satapathy, I. Al-Omari, S. Aich
ABSTRACT NiMnGa-based Heusler alloys are known for their shape-memory effect. However, in this study, the focus will be on the magneto-thermal (magnetocaloric) properties of rapidly solidified Ni50Mn28Ga22 ribbons melt spun at 1300 and 1600 RPM as well as annealed bulk specimens. The ribbons, both as-spun and annealed, and the annealed bulk specimens were tested in a SQUID to determine the magnetic properties at a field of 50 kOe with a temperature step of 3 K in the temperature range 355–385 K. The magnetic data from the isotherms were used to achieve Arrott plots. Second-order transitions were observed in the materials at the TC temperature. The values of magnetic entropy ΔSm were calculated from the magnetic data and these were further used to calculate the values of refrigeration capacity RC. The highest RC value of 273 J/kg was obtained for 1300NMG5 800 where 1300, 800 and 5, represent the melt spinning rate in RPM, the annealing temperature in Celsius and the duration of annealing in hours, respectively. The values of ΔSm were similar for all the ribbons. To confirm the order of the magnetic transition, universal curves were plotted which led to the conclusion that the transformation at the Curie temperature is a second-order ferromagnetic to paramagnetic transition.
{"title":"Magnetocaloric properties of Ni50Mn28Ga22 melt-spun ribbons","authors":"D. K. Satapathy, I. Al-Omari, S. Aich","doi":"10.1080/09500839.2021.1962015","DOIUrl":"https://doi.org/10.1080/09500839.2021.1962015","url":null,"abstract":"ABSTRACT\u0000 NiMnGa-based Heusler alloys are known for their shape-memory effect. However, in this study, the focus will be on the magneto-thermal (magnetocaloric) properties of rapidly solidified Ni50Mn28Ga22 ribbons melt spun at 1300 and 1600 RPM as well as annealed bulk specimens. The ribbons, both as-spun and annealed, and the annealed bulk specimens were tested in a SQUID to determine the magnetic properties at a field of 50 kOe with a temperature step of 3 K in the temperature range 355–385 K. The magnetic data from the isotherms were used to achieve Arrott plots. Second-order transitions were observed in the materials at the TC temperature. The values of magnetic entropy ΔSm were calculated from the magnetic data and these were further used to calculate the values of refrigeration capacity RC. The highest RC value of 273 J/kg was obtained for 1300NMG5 800 where 1300, 800 and 5, represent the melt spinning rate in RPM, the annealing temperature in Celsius and the duration of annealing in hours, respectively. The values of ΔSm were similar for all the ribbons. To confirm the order of the magnetic transition, universal curves were plotted which led to the conclusion that the transformation at the Curie temperature is a second-order ferromagnetic to paramagnetic transition.","PeriodicalId":19860,"journal":{"name":"Philosophical Magazine Letters","volume":"102 1","pages":"1 - 14"},"PeriodicalIF":1.2,"publicationDate":"2021-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42296566","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT The change in the fractal structure of anthracite mined in Jincheng, China, during high-temperature (1200°C) carbonisation was studied in situ by small-angle X-ray scattering (SAXS) at Beijing Synchrotron Radiation Facility (BSRF). The results show that, during carbonisation, the anthracite structure changes from a pore fractal to a surface fractal and then back to a pore fractal. With increase of temperature, the fractal dimension of the sample presents a trend of rise, decline, rise and decline again, which probably corresponds to the four stages of physical desorption, thermal decomposition, thermal condensation, and residual carbon aging in the process of carbonisation. The pore fractal exists in the initial and final stages, and the surface fractal exists in the middle two stages.
{"title":"In-situ SAXS study on fractal of Jincheng anthracite during high-temperature carbonisation","authors":"Yuexiang Wang, Zhihong Li, Jiao Kong, L. Chang, Dongfeng Li, Baoliang Lv","doi":"10.1080/09500839.2021.1936259","DOIUrl":"https://doi.org/10.1080/09500839.2021.1936259","url":null,"abstract":"ABSTRACT\u0000 The change in the fractal structure of anthracite mined in Jincheng, China, during high-temperature (1200°C) carbonisation was studied in situ by small-angle X-ray scattering (SAXS) at Beijing Synchrotron Radiation Facility (BSRF). The results show that, during carbonisation, the anthracite structure changes from a pore fractal to a surface fractal and then back to a pore fractal. With increase of temperature, the fractal dimension of the sample presents a trend of rise, decline, rise and decline again, which probably corresponds to the four stages of physical desorption, thermal decomposition, thermal condensation, and residual carbon aging in the process of carbonisation. The pore fractal exists in the initial and final stages, and the surface fractal exists in the middle two stages.","PeriodicalId":19860,"journal":{"name":"Philosophical Magazine Letters","volume":"101 1","pages":"320 - 329"},"PeriodicalIF":1.2,"publicationDate":"2021-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09500839.2021.1936259","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42947235","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-08-03DOI: 10.1080/09500839.2021.1933642
L. Hu, M. Lin, B. Wei
ABSTRACT The thermophysical properties of refractory MoNbReTaW high-entropy alloy in both supercooled liquid and high-temperature solid states were explored by an electrostatic levitation technique. The maximum supercooling attains 504 K, and the hypercooling limit is derived as 571 K. The liquid density at liquidus temperature is measured to be 13.3 g cm−3, which increases linearly with decreasing temperature at a slope of 6.83 × 10−4 g cm−3 K−1. The liquid alloy exhibits 5.3% relative volume shrinkage during crystallization. The thermal expansion coefficient of liquid and solid alloy at liquidus temperature are determined as 5.0 × 10−5 K−1 and 3.6 ×10−5 K−1, respectively. The liquid specific heat at liquidus temperature is found to be 38.2 J mol−1 K−1, and basically displays a linear decreasing tendency with temperature. According to the calculated enthalpy of fusion 24.7 kJ mol−1 and measured specific heats, the temperature-dependent entropy and Gibbs free energy difference between supercooled liquid and crystalline solid are obtained.
摘要:采用静电悬浮技术研究了难熔MoNbReTaW高熵合金在过冷液体和高温固体状态下的热物理性质。最大过冷度为504 K，过冷极限为571 K。液相温度下的液体密度为13.3 g cm−3，随温度的降低以6.83 × 10−4 g cm−3 K−1的斜率线性增加。结晶过程中，液态合金的相对体积收缩率为5.3%。液相温度下，液态和固态合金的热膨胀系数分别为5.0 ×10−5 K−1和3.6 ×10−5 K−1。液相温度下的液体比热为38.2 J mol−1 K−1，随温度升高基本呈线性降低趋势。根据计算的熔合焓24.7 kJ mol−1和测量的比热，得到过冷液体和结晶固体的温度依赖熵和吉布斯自由能差。
{"title":"Hypercooling limit and physical properties of liquid MoNbReTaW refractory high-entropy alloy","authors":"L. Hu, M. Lin, B. Wei","doi":"10.1080/09500839.2021.1933642","DOIUrl":"https://doi.org/10.1080/09500839.2021.1933642","url":null,"abstract":"ABSTRACT The thermophysical properties of refractory MoNbReTaW high-entropy alloy in both supercooled liquid and high-temperature solid states were explored by an electrostatic levitation technique. The maximum supercooling attains 504 K, and the hypercooling limit is derived as 571 K. The liquid density at liquidus temperature is measured to be 13.3 g cm−3, which increases linearly with decreasing temperature at a slope of 6.83 × 10−4 g cm−3 K−1. The liquid alloy exhibits 5.3% relative volume shrinkage during crystallization. The thermal expansion coefficient of liquid and solid alloy at liquidus temperature are determined as 5.0 × 10−5 K−1 and 3.6 ×10−5 K−1, respectively. The liquid specific heat at liquidus temperature is found to be 38.2 J mol−1 K−1, and basically displays a linear decreasing tendency with temperature. According to the calculated enthalpy of fusion 24.7 kJ mol−1 and measured specific heats, the temperature-dependent entropy and Gibbs free energy difference between supercooled liquid and crystalline solid are obtained.","PeriodicalId":19860,"journal":{"name":"Philosophical Magazine Letters","volume":"101 1","pages":"312 - 319"},"PeriodicalIF":1.2,"publicationDate":"2021-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09500839.2021.1933642","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43931040","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-08-03DOI: 10.1080/09500839.2021.1933235
Pengfei Zhang, Yuxin Li
ABSTRACT Ni–Cu composite coatings have been fabricated on a 6061 aluminium alloy surface using a pulsed Nd-YAG laser. The basic coating was Ni–Cu powder with a Ni:Cu ratio of 4:1. The effects of adding to this powder 0.9 wt.% CeO2, 0.9 wt.% Si and 0.9 wt.% Co on the microstructure, microhardness and wear properties of the coatings have been investigated. The results show that, on adding the CeO2, Si or Co powders, the microstructure of the top region of the coating is mainly composed of equiaxed grains, dendritic crystals and fine equiaxed crystals, whereas the bottom region mainly consists of long rod-like, dendritic crystals and some particles. The average microhardness of the 99.1 wt.% Ni–Cu + 0.9 wt.% CeO2 coating is 529.05 HV, which was about four times higher than that of the bare 6061 aluminium alloy. In addition, the average friction coefficient decreased on adding CeO2, Si and Co powder to the Ni–Cu composite coating.
{"title":"Effects of CeO2, Si and Co on the microstructure and properties of Ni–Cu composite coating on 6061 aluminium alloy by laser cladding","authors":"Pengfei Zhang, Yuxin Li","doi":"10.1080/09500839.2021.1933235","DOIUrl":"https://doi.org/10.1080/09500839.2021.1933235","url":null,"abstract":"ABSTRACT Ni–Cu composite coatings have been fabricated on a 6061 aluminium alloy surface using a pulsed Nd-YAG laser. The basic coating was Ni–Cu powder with a Ni:Cu ratio of 4:1. The effects of adding to this powder 0.9 wt.% CeO2, 0.9 wt.% Si and 0.9 wt.% Co on the microstructure, microhardness and wear properties of the coatings have been investigated. The results show that, on adding the CeO2, Si or Co powders, the microstructure of the top region of the coating is mainly composed of equiaxed grains, dendritic crystals and fine equiaxed crystals, whereas the bottom region mainly consists of long rod-like, dendritic crystals and some particles. The average microhardness of the 99.1 wt.% Ni–Cu + 0.9 wt.% CeO2 coating is 529.05 HV, which was about four times higher than that of the bare 6061 aluminium alloy. In addition, the average friction coefficient decreased on adding CeO2, Si and Co powder to the Ni–Cu composite coating.","PeriodicalId":19860,"journal":{"name":"Philosophical Magazine Letters","volume":"101 1","pages":"303 - 311"},"PeriodicalIF":1.2,"publicationDate":"2021-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09500839.2021.1933235","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42789435","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-07-19DOI: 10.1080/09500839.2021.1953713
S. Motozuka, H. Sato, H. Kuwata, Mitsuo Bito, Y. Okazaki
ABSTRACT Fe-based nanocrystalline alloy powder prepared by ball-milling is a potential candidate as a soft magnetic composite (SMC). Since the magnetic properties of particles having a random geometry arising from brittle fracture deteriorate by the presence of a demagnetising field, plastically deformed flake-shaped powders, exhibiting better magnetic properties on account of the suppression of any demagnetising field, are desirable. Microstructure such as grain size, lattice distortion and the distribution of dislocations, are affected by ball-milling treatment which changes the magnetic properties. In this study, Fe-based nanocrystalline alloy sheets are ball-milled with lubricant oil as a process control agent (PCA) and the microstructure of the particles investigated. The PCA effectively suppresses the brittle fracture of the alloy sheet during the ball-milling treatment and plastically deformed flake-shaped particles are then successfully obtained. Transmission electron microscopy reveals that there were few lattice defects in the α-Fe grain of the alloy, which indicated that almost only grain-boundary-mediated processes such as GB diffusion/sliding/migration and grain rotation dominate the deformation mechanism. However, Williamson–Hall analysis based on synchrotron radiation exhibits a slope indicating micro-strain in the α-Fe grains. It is found that the plastic deformation induced by the ball-milling treatment forms a microstructure having lattice distortion but containing few lattice defects. It is considered that a slight growth of the existing grains, which can be induced by thermal treatment, can achieve a strain- and dislocation-free microstructure, which is desirable for soft magnetic alloys.
{"title":"Preparation of flake-shaped Fe-based nanocrystalline soft magnetic alloy particles subjected to plastic deformation","authors":"S. Motozuka, H. Sato, H. Kuwata, Mitsuo Bito, Y. Okazaki","doi":"10.1080/09500839.2021.1953713","DOIUrl":"https://doi.org/10.1080/09500839.2021.1953713","url":null,"abstract":"ABSTRACT Fe-based nanocrystalline alloy powder prepared by ball-milling is a potential candidate as a soft magnetic composite (SMC). Since the magnetic properties of particles having a random geometry arising from brittle fracture deteriorate by the presence of a demagnetising field, plastically deformed flake-shaped powders, exhibiting better magnetic properties on account of the suppression of any demagnetising field, are desirable. Microstructure such as grain size, lattice distortion and the distribution of dislocations, are affected by ball-milling treatment which changes the magnetic properties. In this study, Fe-based nanocrystalline alloy sheets are ball-milled with lubricant oil as a process control agent (PCA) and the microstructure of the particles investigated. The PCA effectively suppresses the brittle fracture of the alloy sheet during the ball-milling treatment and plastically deformed flake-shaped particles are then successfully obtained. Transmission electron microscopy reveals that there were few lattice defects in the α-Fe grain of the alloy, which indicated that almost only grain-boundary-mediated processes such as GB diffusion/sliding/migration and grain rotation dominate the deformation mechanism. However, Williamson–Hall analysis based on synchrotron radiation exhibits a slope indicating micro-strain in the α-Fe grains. It is found that the plastic deformation induced by the ball-milling treatment forms a microstructure having lattice distortion but containing few lattice defects. It is considered that a slight growth of the existing grains, which can be induced by thermal treatment, can achieve a strain- and dislocation-free microstructure, which is desirable for soft magnetic alloys.","PeriodicalId":19860,"journal":{"name":"Philosophical Magazine Letters","volume":"101 1","pages":"399 - 407"},"PeriodicalIF":1.2,"publicationDate":"2021-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09500839.2021.1953713","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47501680","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-07-14DOI: 10.1080/09500839.2021.1950933
Xiao-Tong Li, Xiaozhi Tang, Ya-Fang Guo
ABSTRACT The reorientation of a titanium–vacancy complex in a vanadium alloy with and without the presence of a grain boundary (GB) is investigated by atomistic simulations. The results show that a second-nearest-neighbour complex is a common transition state during the reorientation. Also, the atomic composition of a GB may affect the activation energy for reorientations: atoms with a high potential energy at a ∑3{111} GB significantly affect the activation energy, while those at a ∑3{112} GB have a weaker effect.
{"title":"Reorientation of a titanium–vacancy complex in a vanadium alloy","authors":"Xiao-Tong Li, Xiaozhi Tang, Ya-Fang Guo","doi":"10.1080/09500839.2021.1950933","DOIUrl":"https://doi.org/10.1080/09500839.2021.1950933","url":null,"abstract":"ABSTRACT The reorientation of a titanium–vacancy complex in a vanadium alloy with and without the presence of a grain boundary (GB) is investigated by atomistic simulations. The results show that a second-nearest-neighbour complex is a common transition state during the reorientation. Also, the atomic composition of a GB may affect the activation energy for reorientations: atoms with a high potential energy at a ∑3{111} GB significantly affect the activation energy, while those at a ∑3{112} GB have a weaker effect.","PeriodicalId":19860,"journal":{"name":"Philosophical Magazine Letters","volume":"101 1","pages":"390 - 398"},"PeriodicalIF":1.2,"publicationDate":"2021-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09500839.2021.1950933","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48529768","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-07-14DOI: 10.1080/09500839.2021.1949066
Susumu Yamada
ABSTRACT This study analysed the electronic structures of dislocations in 9Cr steel using a spherical aberration-corrected scanning transmission electron microscope equipped with a monochromated electron energy-loss spectroscope. This is the first study to report that dislocations broaden a zero-loss peak (ZLP) and also induce an absorption phenomenon at approximately 0.5 eV in the ZLP tail, which are interpreted to be related to phonon scatterings by dislocations and interference effect of multiple beams, respectively. This work also experimentally demonstrates that the use of a spectrum-imaging method allows imaging of dislocations through ZLP broadening. The approach proposed herein is a promising technique for detecting dislocations in high Cr steel.
{"title":"Dislocation imaging through mapping based on the combination of an electron energy-loss spectroscope with a scanning transmission electron microscope","authors":"Susumu Yamada","doi":"10.1080/09500839.2021.1949066","DOIUrl":"https://doi.org/10.1080/09500839.2021.1949066","url":null,"abstract":"ABSTRACT This study analysed the electronic structures of dislocations in 9Cr steel using a spherical aberration-corrected scanning transmission electron microscope equipped with a monochromated electron energy-loss spectroscope. This is the first study to report that dislocations broaden a zero-loss peak (ZLP) and also induce an absorption phenomenon at approximately 0.5 eV in the ZLP tail, which are interpreted to be related to phonon scatterings by dislocations and interference effect of multiple beams, respectively. This work also experimentally demonstrates that the use of a spectrum-imaging method allows imaging of dislocations through ZLP broadening. The approach proposed herein is a promising technique for detecting dislocations in high Cr steel.","PeriodicalId":19860,"journal":{"name":"Philosophical Magazine Letters","volume":"101 1","pages":"381 - 389"},"PeriodicalIF":1.2,"publicationDate":"2021-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09500839.2021.1949066","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44432394","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-07-06DOI: 10.1080/09500839.2021.1948130
K. Sasidhar, M. Gururajan, S. Meka
ABSTRACT The effect of crystallographically oriented, unidirectional concentration gradients on spinodal decomposition in cubic crystalline solids with elastic and interfacial energy anisotropy is discussed. Phase-field simulations reveal that the kinetics of spinodal decomposition occurring in such systems is dependent on the degree of misorientation between the direction of composition gradient and the preferred crystallographic orientation for growth of spinodal fluctuations; the larger is the misorientation, the slower the kinetics. This phenomenon has been used to explain the well-known grain-orientation-dependent N-uptake kinetics observed during nitriding of metallic alloys. Several plausible causes have been proposed in the literature for the grain-orientation-dependent N-uptake kinetics during nitriding. However, this study reveals that this phenomenon is observed exclusively and without exception in alloy systems having a spinodal instability. The N-uptake kinetics in such systems is known to be dependent on the kinetics of spinodal decomposition. Consequently, anisotropic spinodal decomposition kinetics occurring owing to the presence of a surface-directed N-composition gradient in poly-crystalline metals has been shown to be a more fundamental cause for the phenomenon.
{"title":"Concentration-gradient-driven anisotropic spinodal decomposition kinetics: nitriding of metallic alloys","authors":"K. Sasidhar, M. Gururajan, S. Meka","doi":"10.1080/09500839.2021.1948130","DOIUrl":"https://doi.org/10.1080/09500839.2021.1948130","url":null,"abstract":"ABSTRACT The effect of crystallographically oriented, unidirectional concentration gradients on spinodal decomposition in cubic crystalline solids with elastic and interfacial energy anisotropy is discussed. Phase-field simulations reveal that the kinetics of spinodal decomposition occurring in such systems is dependent on the degree of misorientation between the direction of composition gradient and the preferred crystallographic orientation for growth of spinodal fluctuations; the larger is the misorientation, the slower the kinetics. This phenomenon has been used to explain the well-known grain-orientation-dependent N-uptake kinetics observed during nitriding of metallic alloys. Several plausible causes have been proposed in the literature for the grain-orientation-dependent N-uptake kinetics during nitriding. However, this study reveals that this phenomenon is observed exclusively and without exception in alloy systems having a spinodal instability. The N-uptake kinetics in such systems is known to be dependent on the kinetics of spinodal decomposition. Consequently, anisotropic spinodal decomposition kinetics occurring owing to the presence of a surface-directed N-composition gradient in poly-crystalline metals has been shown to be a more fundamental cause for the phenomenon.","PeriodicalId":19860,"journal":{"name":"Philosophical Magazine Letters","volume":"101 1","pages":"432 - 443"},"PeriodicalIF":1.2,"publicationDate":"2021-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09500839.2021.1948130","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45436988","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-07-03DOI: 10.1080/09500839.2021.1922775
A. Jabar, R. Masrour, M. Hamedoun, A. Benyoussef, A. Hourmatallah, N. Benzakour, A. Rezzouk, K. Bouslykhane, J. Kharbach
ABSTRACT The magnetic properties and magnetic phase transition in square-octagon lattice with mixed spins 3/2 and 5/2 were investigated by Monte Carlo simulations. The ground state phase diagrams of square-octagon structure were obtained under the effect of crystal field and exchange interactions. The thermal partial, total magnetizations and magnetic susceptibilities of square-octagon lattice are obtained for a fixed magnetic parameter. The reduced Néel temperature is noticed. The variation of total magnetizations with the crystal field of square-octagon structure is shown. The magnetic hysteresis cycle of square-octagon structure, with mixed spins S = 3/2 and σ = 5/2 for several exchange interactions, temperatures and crystal fields, is found.
{"title":"Magnetic properties and magnetic phase transition in square-octagon lattice: Monte Carlo study","authors":"A. Jabar, R. Masrour, M. Hamedoun, A. Benyoussef, A. Hourmatallah, N. Benzakour, A. Rezzouk, K. Bouslykhane, J. Kharbach","doi":"10.1080/09500839.2021.1922775","DOIUrl":"https://doi.org/10.1080/09500839.2021.1922775","url":null,"abstract":"ABSTRACT The magnetic properties and magnetic phase transition in square-octagon lattice with mixed spins 3/2 and 5/2 were investigated by Monte Carlo simulations. The ground state phase diagrams of square-octagon structure were obtained under the effect of crystal field and exchange interactions. The thermal partial, total magnetizations and magnetic susceptibilities of square-octagon lattice are obtained for a fixed magnetic parameter. The reduced Néel temperature is noticed. The variation of total magnetizations with the crystal field of square-octagon structure is shown. The magnetic hysteresis cycle of square-octagon structure, with mixed spins S = 3/2 and σ = 5/2 for several exchange interactions, temperatures and crystal fields, is found.","PeriodicalId":19860,"journal":{"name":"Philosophical Magazine Letters","volume":"101 1","pages":"293 - 302"},"PeriodicalIF":1.2,"publicationDate":"2021-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09500839.2021.1922775","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44966234","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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