Pub Date : 2021-04-09DOI: 10.1080/09500839.2021.1909167
L. Pizzagalli
ABSTRACT Silicon carbide is an important material with applications in numerous domains, but for which our knowledge of basic properties like elastic constants is surprisingly limited. Although several density functional theory calculations have been reported, those are usually not accurate enough, with a sizeable dispersion of published values. A heuristic method is proposed here, allowing for largely reducing the uncertainty. It is based on the use of a weighted average of errors for two reference materials, Si and C. It is demonstrated that this method is effective for physical properties like the lattice parameter and the bulk modulus. It is then used for determining the full sets of elastic constants for the 3C, 2H, 4H, and 6H silicon carbide polytypes.
{"title":"Accurate values of 3C, 2H, 4H, and 6H SiC elastic constants using DFT calculations and heuristic errors corrections","authors":"L. Pizzagalli","doi":"10.1080/09500839.2021.1909167","DOIUrl":"https://doi.org/10.1080/09500839.2021.1909167","url":null,"abstract":"ABSTRACT Silicon carbide is an important material with applications in numerous domains, but for which our knowledge of basic properties like elastic constants is surprisingly limited. Although several density functional theory calculations have been reported, those are usually not accurate enough, with a sizeable dispersion of published values. A heuristic method is proposed here, allowing for largely reducing the uncertainty. It is based on the use of a weighted average of errors for two reference materials, Si and C. It is demonstrated that this method is effective for physical properties like the lattice parameter and the bulk modulus. It is then used for determining the full sets of elastic constants for the 3C, 2H, 4H, and 6H silicon carbide polytypes.","PeriodicalId":19860,"journal":{"name":"Philosophical Magazine Letters","volume":"101 1","pages":"242 - 252"},"PeriodicalIF":1.2,"publicationDate":"2021-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09500839.2021.1909167","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48931914","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 : 2021-04-03DOI: 10.1080/09500839.2021.1881641
Eric Osei-Agyemang, G. Balasubramanian
ABSTRACT We employ first-principles calculations to examine the role of oxidation on the thermal expansion behaviour of a refractory multicomponent alloy. Our results reveal that the linear expansion and the coefficient of volumetric expansion over a range of temperatures have higher values for the oxidised alloy than the pure material. The enhanced expansion for the oxidised alloy is attributed to significant changes in the lattice parameter of the alloy upon surface oxidation. During oxidation, the diffusion of oxygen atoms to the subsurface layer of the alloy after complete surface coverage produces a displacement of the constituent elements that form metal oxides. This depletion creates vacancy sites in the lattice for enabling enhanced expansivity in the oxidised structure relative to the pure refractory alloy.
{"title":"Effect of oxidation on the thermal expansion of a refractory multicomponent alloy","authors":"Eric Osei-Agyemang, G. Balasubramanian","doi":"10.1080/09500839.2021.1881641","DOIUrl":"https://doi.org/10.1080/09500839.2021.1881641","url":null,"abstract":"ABSTRACT We employ first-principles calculations to examine the role of oxidation on the thermal expansion behaviour of a refractory multicomponent alloy. Our results reveal that the linear expansion and the coefficient of volumetric expansion over a range of temperatures have higher values for the oxidised alloy than the pure material. The enhanced expansion for the oxidised alloy is attributed to significant changes in the lattice parameter of the alloy upon surface oxidation. During oxidation, the diffusion of oxygen atoms to the subsurface layer of the alloy after complete surface coverage produces a displacement of the constituent elements that form metal oxides. This depletion creates vacancy sites in the lattice for enabling enhanced expansivity in the oxidised structure relative to the pure refractory alloy.","PeriodicalId":19860,"journal":{"name":"Philosophical Magazine Letters","volume":"101 1","pages":"173 - 182"},"PeriodicalIF":1.2,"publicationDate":"2021-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09500839.2021.1881641","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46452153","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 : 2021-04-03DOI: 10.1080/09500839.2021.1873446
Chenyang Zhu, L. Dong, Bin Hu, Bing Chen
ABSTRACT The evolution of microstructure and the variation of strain field induced by precipitation in Al–Si–Mg–Cu alloy with high copper content during early ageing is characterised by high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and geometric phase analysis (GPA) calculations. The basic building blocks for GP zones and step-shaped edges around subsequent precipitation are characterised. Incorporation of solute atoms, namely Si, Mg and Cu, accounts for the expansion of GP zones with core–shell structure and further precipitation transformation. The induced strain field rises as the ageing time increases and structural transformation proceeds, which results in a hardening of the sample.
{"title":"Evolution of microstructure and strain field by precipitation during early ageing of Al–Si–Mg–Cu alloy","authors":"Chenyang Zhu, L. Dong, Bin Hu, Bing Chen","doi":"10.1080/09500839.2021.1873446","DOIUrl":"https://doi.org/10.1080/09500839.2021.1873446","url":null,"abstract":"ABSTRACT The evolution of microstructure and the variation of strain field induced by precipitation in Al–Si–Mg–Cu alloy with high copper content during early ageing is characterised by high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and geometric phase analysis (GPA) calculations. The basic building blocks for GP zones and step-shaped edges around subsequent precipitation are characterised. Incorporation of solute atoms, namely Si, Mg and Cu, accounts for the expansion of GP zones with core–shell structure and further precipitation transformation. The induced strain field rises as the ageing time increases and structural transformation proceeds, which results in a hardening of the sample.","PeriodicalId":19860,"journal":{"name":"Philosophical Magazine Letters","volume":"101 1","pages":"143 - 153"},"PeriodicalIF":1.2,"publicationDate":"2021-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09500839.2021.1873446","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48694513","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 : 2021-04-03DOI: 10.1080/09500839.2021.1877366
B. Sagar, K. Biswas, R. Mukherjee
ABSTRACT In the present work, we adopt a computational approach to study the evolution of microstructure during solidification of a Ti-Fe-Co-Ni-Cu multi-component alloy system by regarding it as a Ti-(Cu, Ni)-(Fe, Co) pseudo-ternary-alloy system. The as-cast alloy has a eutectic morphology with lamellar structure between (Cu)SS and a Laves phase. A Kim-Kim-Suzuki (KKS) phase-field model for eutectic solidification is implemented for this multi-component alloy system using a MOOSE finite element framework. The model is implemented for different scenarios, which include the simulation of microstructures at eutectic temperature and for small degrees of undercoolings (ΔT = 2°C, 5°C, 8°C, 10°C). Analysis of the microstructure evolution reveals that an increase in undercooling leads to a higher growth velocity and a larger volume fraction of solid phases. GRAPHICAL ABSTRACT
{"title":"A phase-field study on a eutectic high-entropy alloy during solidification","authors":"B. Sagar, K. Biswas, R. Mukherjee","doi":"10.1080/09500839.2021.1877366","DOIUrl":"https://doi.org/10.1080/09500839.2021.1877366","url":null,"abstract":"ABSTRACT In the present work, we adopt a computational approach to study the evolution of microstructure during solidification of a Ti-Fe-Co-Ni-Cu multi-component alloy system by regarding it as a Ti-(Cu, Ni)-(Fe, Co) pseudo-ternary-alloy system. The as-cast alloy has a eutectic morphology with lamellar structure between (Cu)SS and a Laves phase. A Kim-Kim-Suzuki (KKS) phase-field model for eutectic solidification is implemented for this multi-component alloy system using a MOOSE finite element framework. The model is implemented for different scenarios, which include the simulation of microstructures at eutectic temperature and for small degrees of undercoolings (ΔT = 2°C, 5°C, 8°C, 10°C). Analysis of the microstructure evolution reveals that an increase in undercooling leads to a higher growth velocity and a larger volume fraction of solid phases. GRAPHICAL ABSTRACT","PeriodicalId":19860,"journal":{"name":"Philosophical Magazine Letters","volume":"101 1","pages":"160 - 172"},"PeriodicalIF":1.2,"publicationDate":"2021-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09500839.2021.1877366","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47273855","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 : 2021-04-03DOI: 10.1080/09500839.2021.1874068
E. Eser, H. Koç
ABSTRACT The specific heat capacity of half-Heusler ScNiSb and TmNiSb compounds have been calculated using a simple approximation in the temperature range 0–298 K. The results obtained for the specific heat capacities are in good agreement with the experimental data in the literature. The Debye temperatures were derived by fitting the analytical expression obtained in this study to experimental data. The Debye temperatures and the Sommerfeld coefficients resulting from the fitting are 355.95 K and 7.19 mJ/mol.K for ScNiSb, and 234.5 K and 14.92 mJ/mol.K for TmNiSb.
{"title":"Theoretical study of specific heat capacity of thermoelectric half-Heusler XNiSb (X = Sc, Tm) compounds","authors":"E. Eser, H. Koç","doi":"10.1080/09500839.2021.1874068","DOIUrl":"https://doi.org/10.1080/09500839.2021.1874068","url":null,"abstract":"ABSTRACT The specific heat capacity of half-Heusler ScNiSb and TmNiSb compounds have been calculated using a simple approximation in the temperature range 0–298 K. The results obtained for the specific heat capacities are in good agreement with the experimental data in the literature. The Debye temperatures were derived by fitting the analytical expression obtained in this study to experimental data. The Debye temperatures and the Sommerfeld coefficients resulting from the fitting are 355.95 K and 7.19 mJ/mol.K for ScNiSb, and 234.5 K and 14.92 mJ/mol.K for TmNiSb.","PeriodicalId":19860,"journal":{"name":"Philosophical Magazine Letters","volume":"101 1","pages":"154 - 159"},"PeriodicalIF":1.2,"publicationDate":"2021-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09500839.2021.1874068","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42630808","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 : 2021-04-01DOI: 10.1080/09500839.2021.1905192
Y. Ikoma, T. Yamasaki, T. Masuda, Y. Tange, Y. Higo, Y. Ohishi, M. McCartney, David J. Smith, Z. Horita
ABSTRACT In situ observation of a phase transformation during annealing of Si containing diamond-cubic (dc) and metastable phases has been performed using synchrotron X-ray diffraction. Metastable body-centred-cubic (bc8) and rhombohedral (r8) phases were formed by high-pressure torsion. These metastable phases gradually disappeared when increasing the annealing temperature to ∼ 180°C while another metastable phase having a hexagonal diamond (hd) structure appeared at ∼ 190°C. High-resolution transmission microscopy analysis revealed that hd and dc grains were present after annealing at 200°C. The results indicate that a phase transformation, mainly from bc8 to hd, occurred during annealing.
{"title":"Synchrotron X-ray diffraction observation of phase transformation during annealing of Si processed by high-pressure torsion","authors":"Y. Ikoma, T. Yamasaki, T. Masuda, Y. Tange, Y. Higo, Y. Ohishi, M. McCartney, David J. Smith, Z. Horita","doi":"10.1080/09500839.2021.1905192","DOIUrl":"https://doi.org/10.1080/09500839.2021.1905192","url":null,"abstract":"ABSTRACT In situ observation of a phase transformation during annealing of Si containing diamond-cubic (dc) and metastable phases has been performed using synchrotron X-ray diffraction. Metastable body-centred-cubic (bc8) and rhombohedral (r8) phases were formed by high-pressure torsion. These metastable phases gradually disappeared when increasing the annealing temperature to ∼ 180°C while another metastable phase having a hexagonal diamond (hd) structure appeared at ∼ 190°C. High-resolution transmission microscopy analysis revealed that hd and dc grains were present after annealing at 200°C. The results indicate that a phase transformation, mainly from bc8 to hd, occurred during annealing.","PeriodicalId":19860,"journal":{"name":"Philosophical Magazine Letters","volume":"101 1","pages":"223 - 231"},"PeriodicalIF":1.2,"publicationDate":"2021-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09500839.2021.1905192","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44051356","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 : 2021-03-29DOI: 10.1080/09500839.2021.1904300
S. Pan, B. He
ABSTRACT The present work quantifies the contribution of constituting phases to the strain hardening in a medium-Mn steel during Lüders deformation. The strain hardening of the ferrite matrix (∼ 46.1 MPa) is much lower than that of the austenite phase (∼ 116 MPa). The large difference of strain hardening behaviour between ferrite and austenite phases is ascribed to a martensitic transformation. Thus, the transformation-induced plasticity effect in retained austenite is the main contributor to the strain hardening during Lüders deformation of the present medium-Mn steel.
{"title":"The respective strain hardening of constituting phases during Lüders deformation of a medium-Mn steel","authors":"S. Pan, B. He","doi":"10.1080/09500839.2021.1904300","DOIUrl":"https://doi.org/10.1080/09500839.2021.1904300","url":null,"abstract":"ABSTRACT The present work quantifies the contribution of constituting phases to the strain hardening in a medium-Mn steel during Lüders deformation. The strain hardening of the ferrite matrix (∼ 46.1 MPa) is much lower than that of the austenite phase (∼ 116 MPa). The large difference of strain hardening behaviour between ferrite and austenite phases is ascribed to a martensitic transformation. Thus, the transformation-induced plasticity effect in retained austenite is the main contributor to the strain hardening during Lüders deformation of the present medium-Mn steel.","PeriodicalId":19860,"journal":{"name":"Philosophical Magazine Letters","volume":"101 1","pages":"211 - 221"},"PeriodicalIF":1.2,"publicationDate":"2021-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09500839.2021.1904300","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41876642","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 : 2021-03-29DOI: 10.1080/09500839.2021.1903605
Qiang Xian, Xinmiao He, Li Chen, Enchao Wang, Hui Dan, Yi Ding
ABSTRACT Mesoporous SBA-15 has been synthesised using a binary acid H2SO4 as media. The effects of H2SO4 concentration and synthesis temperature on the morphologies and mesostructures of the obtained mesoporous SBA-15 materials were studied. The results revealed that the more-ordered structure was obtained at a H2SO4 concentration of 2 M, while a higher H2SO4 concentration of 3 M led to a less-ordered structure. In addition, with increasing H2SO4 concentration from 1 to 3 M, the morphologies of SBA-15 particles transferred from rod-like to sphere-like. This work demonstrated that mesoporous SBA-15 with various textural properties and morphologies can be feasibly obtained by controlling the H2SO4 concentration and synthesis temperature.
{"title":"Controllable synthesis of mesoporous SBA-15 using H2SO4","authors":"Qiang Xian, Xinmiao He, Li Chen, Enchao Wang, Hui Dan, Yi Ding","doi":"10.1080/09500839.2021.1903605","DOIUrl":"https://doi.org/10.1080/09500839.2021.1903605","url":null,"abstract":"ABSTRACT Mesoporous SBA-15 has been synthesised using a binary acid H2SO4 as media. The effects of H2SO4 concentration and synthesis temperature on the morphologies and mesostructures of the obtained mesoporous SBA-15 materials were studied. The results revealed that the more-ordered structure was obtained at a H2SO4 concentration of 2 M, while a higher H2SO4 concentration of 3 M led to a less-ordered structure. In addition, with increasing H2SO4 concentration from 1 to 3 M, the morphologies of SBA-15 particles transferred from rod-like to sphere-like. This work demonstrated that mesoporous SBA-15 with various textural properties and morphologies can be feasibly obtained by controlling the H2SO4 concentration and synthesis temperature.","PeriodicalId":19860,"journal":{"name":"Philosophical Magazine Letters","volume":"101 1","pages":"203 - 210"},"PeriodicalIF":1.2,"publicationDate":"2021-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09500839.2021.1903605","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47075543","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 : 2021-03-16DOI: 10.1080/09500839.2021.1900614
S. Mahesh, S. M. Keralavarma
ABSTRACT The two-dimensional stress fields induced by a set of infinitely many parallel edge dislocations are difficult to estimate as those of individual dislocations decay slowly. A simple numerical method to compute them is proposed. The method is based on series summation using a convergence factor, that decays rapidly with radial distance r from the field point, and letting the positive parameter numerically through Richardson extrapolation. The present method is more general than a lattice summation method with explicit spurious stress cancellation that is widely used in the literature. Furthermore, the spurious long-range stresses are cancelled in the present method without explicit evaluation.
{"title":"The stress field of an infinite set of discrete dislocations","authors":"S. Mahesh, S. M. Keralavarma","doi":"10.1080/09500839.2021.1900614","DOIUrl":"https://doi.org/10.1080/09500839.2021.1900614","url":null,"abstract":"ABSTRACT The two-dimensional stress fields induced by a set of infinitely many parallel edge dislocations are difficult to estimate as those of individual dislocations decay slowly. A simple numerical method to compute them is proposed. The method is based on series summation using a convergence factor, that decays rapidly with radial distance r from the field point, and letting the positive parameter numerically through Richardson extrapolation. The present method is more general than a lattice summation method with explicit spurious stress cancellation that is widely used in the literature. Furthermore, the spurious long-range stresses are cancelled in the present method without explicit evaluation.","PeriodicalId":19860,"journal":{"name":"Philosophical Magazine Letters","volume":"101 1","pages":"192 - 202"},"PeriodicalIF":1.2,"publicationDate":"2021-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09500839.2021.1900614","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42226470","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 : 2021-03-04DOI: 10.1080/09500839.2020.1871088
I. Belova, Zi-kui Liu, G. Murch
ABSTRACT In this paper, we study the theory of the diffusion behaviour of a binary alloy in a temperature gradient (thermotransport). Using the Onsager formalism of irreversible thermodynamics we develop exact relations for the heats of transport of each component in terms of various measurable diffusion quantities under steady state conditions and with the vacancies being at local equilibrium. Apparent inconsistencies with some earlier work are indicated. Further relations for heats of transport are then developed in terms of the random alloy model for the Darken and Manning approximations. Relations for the formal separation of the heats of transport are also developed.
{"title":"Exact phenomenological theory for thermotransport in a solid binary alloy","authors":"I. Belova, Zi-kui Liu, G. Murch","doi":"10.1080/09500839.2020.1871088","DOIUrl":"https://doi.org/10.1080/09500839.2020.1871088","url":null,"abstract":"ABSTRACT In this paper, we study the theory of the diffusion behaviour of a binary alloy in a temperature gradient (thermotransport). Using the Onsager formalism of irreversible thermodynamics we develop exact relations for the heats of transport of each component in terms of various measurable diffusion quantities under steady state conditions and with the vacancies being at local equilibrium. Apparent inconsistencies with some earlier work are indicated. Further relations for heats of transport are then developed in terms of the random alloy model for the Darken and Manning approximations. Relations for the formal separation of the heats of transport are also developed.","PeriodicalId":19860,"journal":{"name":"Philosophical Magazine Letters","volume":"101 1","pages":"123 - 131"},"PeriodicalIF":1.2,"publicationDate":"2021-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/09500839.2020.1871088","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46518004","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：