A thermodynamic evaluation of the Cr–Si system was performed concerning the latest experimental phase diagram and with the aid of first-principles calculations. The thermodynamic parameters for the Gibbs energy of pure Cr were modified based on the new experimental value of 1861 °C for the melting point of pure Cr, which was previously reported as 1907 °C in the SGTE database. The Gibbs energy descriptions of the Cr3Si and Cr5Si3 phases were revised using Cr3(Cr,Si)- and (Cr,Si)5Si3-type two-sublattice models to reproduce the latest experimental results of their solubility composition ranges, that is, Cr3Si extending toward the Cr-rich side and Cr5Si3 extending toward the Si-rich side from the stoichiometry. The CrSi and CrSi2 phases were considered line compounds with no solubility range, and the solubility of Cr in the Si phase was ignored. A set of self-consistent thermodynamic parameters for the Cr–Si system was obtained using the CALPHAD technique. The phase diagrams calculated using the optimized parameters showed reasonable agreement with the latest phase equilibrium data and thermodynamic property data in the literature, including the enthalpy of mixing, formation enthalpy, and chemical potential diagrams of Cr and Si in the equilibrium phases.
{"title":"Thermodynamic assessment of the Cr–Si binary system","authors":"Kazushige Ioroi , Ikuo Ohnuma , Xiao Xu , Ryosuke Kainuma , Toshihiro Omori","doi":"10.1016/j.calphad.2024.102690","DOIUrl":"https://doi.org/10.1016/j.calphad.2024.102690","url":null,"abstract":"<div><p>A thermodynamic evaluation of the Cr–Si system was performed concerning the latest experimental phase diagram and with the aid of first-principles calculations. The thermodynamic parameters for the Gibbs energy of pure Cr were modified based on the new experimental value of 1861 °C for the melting point of pure Cr, which was previously reported as 1907 °C in the SGTE database. The Gibbs energy descriptions of the Cr<sub>3</sub>Si and Cr<sub>5</sub>Si<sub>3</sub> phases were revised using Cr<sub>3</sub>(Cr,Si)- and (Cr,Si)<sub>5</sub>Si<sub>3</sub>-type two-sublattice models to reproduce the latest experimental results of their solubility composition ranges, that is, Cr<sub>3</sub>Si extending toward the Cr-rich side and Cr<sub>5</sub>Si<sub>3</sub> extending toward the Si-rich side from the stoichiometry. The CrSi and CrSi<sub>2</sub> phases were considered line compounds with no solubility range, and the solubility of Cr in the Si phase was ignored. A set of self-consistent thermodynamic parameters for the Cr–Si system was obtained using the CALPHAD technique. The phase diagrams calculated using the optimized parameters showed reasonable agreement with the latest phase equilibrium data and thermodynamic property data in the literature, including the enthalpy of mixing, formation enthalpy, and chemical potential diagrams of Cr and Si in the equilibrium phases.</p></div>","PeriodicalId":9436,"journal":{"name":"Calphad-computer Coupling of Phase Diagrams and Thermochemistry","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2024-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140533427","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-04-04DOI: 10.1016/j.calphad.2024.102687
V.P. Vassiliev , A.S. Leonov , S.A. Kulinich
The correct mathematical description of heat capacities Cp in a wide range of temperatures is still unsolved problem. A fragmental description of some phases is like a vision of one part of a large mosaic picture. A single description of Cp or other property of a phase of any isostructural series does not allow one to see the integrity of the entire ensemble. We propose a special mathematical model to describe Cp in a wide temperature range for a whole large class of isostructural sphalerite phases. In the proposed model, it is believed that an ideal crystal does not have any foreign inclusions, defects, or dislocations. The group IV elements (Si, Ge, α-Sn and diamond-like Pb) were taken as the basis, with flerovium (114Fl) closing this group. There should be no other elements in this group according to the fine structure constant (α) (or the Sommerfeld constant). As a consequence, the limiting value of the heat capacities of phases with a sphalerite structure falls on the element 114 (114Fl) and has a value of Cp = 30.5 ± 0.3 J · mol-at−1 · K−1. This value was obtained as a maximal virtual point Cp of the last element (114Fl) of group IV and corresponds to Ln (Cp/R) = 1.30 ± 0.01 for the isotherms ln (Cp/R) vs Ln(N), where N is an atomic number of an element of group IV or the sum of the atomic numbers of AIIIBV or AIIBVI compounds per mole-atom. The common point of heat capacity attributable to flerovium is obtained from the linear equations Ср/R vs Ln(N) at low temperatures from 25 to 35K. For only pure elements of group IV (Si, Ge, α-Sn and diamond-like Pb), flerovium closes this group, and there are no other elements behind it, according to α. The maximum heat capacity of flerovium can be taken as 30.5 J·mol-at−1·K−1 with an accuracy of 1%. As the temperature decreases, this value slowly decreases (within 1%), and then, when it approaches 0 K, it drops sharply to 0 J·mol-at−1·K−1. To describe the set of the isostructural experimental data Cp(T) for diamond-like phases in solid state as a whole system, here we used a special multi-parameter family of functions. For each substance, the parameters are found by minimizing the discrepancy between the theoretical dependence Cp(T) and corresponding experimental data. The dependence of the heat capacities for elements of group IV (Si, Ge, α-Sn, diamond-like Pb, Fl) at fixed temperatures on Ln(N), where N is the atomic number or the demi sum of the atomic numbers of phases AIIBVI or AIIIBV. In this case, ei
在广泛的温度范围内对热容量 Cp 进行正确的数学描述,仍然是一个尚未解决的问题。对某些相的片面描述就像对一幅巨大的马赛克图片中的一个部分的观察。对任何等结构系列中某一相的 Cp 或其他性质的单一描述,并不能让人看到整个集合的完整性。我们提出了一种特殊的数学模型,用于描述整整一大类等结构闪锌矿相在宽温度范围内的 Cp。在提出的模型中,我们认为理想晶体不存在任何外来夹杂物、缺陷或位错。以第四族元素(Si、Ge、α-Sn 和类金刚石铅)为基础,氟铈镧矿(114Fl)结束了这一族群。根据精细结构常数 (α)(或索默费尔德常数),这组元素中不应有其他元素。因此,闪锌矿结构相的热容极限值落在 114 (114Fl) 元素上,其值为 Cp = 30.5 ± 0.3 J - mol-at-1 - K-1。该值是作为第 IV 组最后一种元素 (114Fl) 的最大虚拟点 Cp 得出的,对应于 ln (Cp/R) vs Ln(N) 等温线的 Ln (Cp/R) = 1.30 ± 0.01,其中 N 是第 IV 组元素的原子序数或每摩尔原子 AIIIBV 或 AIIBVI 化合物的原子序数之和。在 25 至 35K 的低温条件下,鈇的热容量共同点可从 Ср/R vs Ln(N) 的线性方程中获得。根据 α,只有纯元素 IV 组(Si、Ge、α-Sn 和类金刚石铅)中的鈇关闭了该组,在它后面没有其他元素。鈇的最大热容量可取为 30.5 J-mol-at-1-K-1,精确度为 1%。随着温度的降低,该值会缓慢减小(在 1%以内),当温度接近 0 K 时,该值会急剧下降至 0 J-mol-at-1-K-1。为了将固态类金刚石相的一组等结构实验数据 Cp(T) 作为一个整体系统来描述,我们在这里使用了一个特殊的多参数函数族。对于每种物质,参数都是通过最小化 Cp(T) 理论依赖性与相应实验数据之间的差异而找到的。第 IV 组元素(Si、Ge、α-Sn、类金刚石铅、Fl)在固定温度下的热容取决于 Ln(N),其中 N 是原子序数或 AIIBVI 相或 AIIIBV 相的原子序数之和。在这种情况下,Ln(N)的参数依赖性要么出现断点,要么出现锗的拐点。
{"title":"Optimizing the heat capacities of sphalerite phases as single system, or how nuclear physics can help physical chemistry","authors":"V.P. Vassiliev , A.S. Leonov , S.A. Kulinich","doi":"10.1016/j.calphad.2024.102687","DOIUrl":"https://doi.org/10.1016/j.calphad.2024.102687","url":null,"abstract":"<div><p>The correct mathematical description of heat capacities <em>C</em><sub>p</sub> in a wide range of temperatures is still unsolved problem. A fragmental description of some phases is like a vision of one part of a large mosaic picture. A single description of <em>C</em><sub>p</sub> or other property of a phase of any isostructural series does not allow one to see the integrity of the entire ensemble. We propose a special mathematical model to describe <em>C</em><sub>p</sub> in a wide temperature range for a whole large class of isostructural sphalerite phases. In the proposed model, it is believed that an ideal crystal does not have any foreign inclusions, defects, or dislocations. The group IV elements (Si, Ge, α-Sn and diamond-like Pb) were taken as the basis, with flerovium (<sup>114</sup>Fl) closing this group. There should be no other elements in this group according to the fine structure constant (<em>α</em>) (or the Sommerfeld constant). As a consequence, the limiting value of the heat capacities of phases with a sphalerite structure falls on the element 114 (<sup>114</sup>Fl) and has a value of <em>C</em><sub>p</sub> = 30.5 ± 0.3 J · mol-at<sup>−1</sup> · K<sup>−1</sup>. This value was obtained as a maximal virtual point <em>C</em><sub>p</sub> of the last element (<sup>114</sup>Fl) of group IV and corresponds to Ln (<em>C</em><sub>p</sub>/<em>R</em>) = 1.30 ± 0.01 for the isotherms ln (<em>C</em><sub>p</sub>/<em>R</em>) vs Ln(<em>N</em>), where <em>N</em> is an atomic number of an element of group IV or the sum of the atomic numbers of A<sup>III</sup>B<sup>V</sup> or A<sup>II</sup>B<sup>VI</sup> compounds per mole-atom. The common point of heat capacity attributable to flerovium is obtained from the linear equations <em>С</em><sub>р</sub>/<em>R</em> vs Ln(<em>N</em>) at low temperatures from 25 to 35K. For only pure elements of group IV (Si, Ge, α-Sn and diamond-like Pb), flerovium closes this group, and there are no other elements behind it, according to <em>α</em>. The maximum heat capacity of flerovium can be taken as 30.5 J·mol-at<sup>−1</sup>·K<sup>−1</sup> with an accuracy of 1%. As the temperature decreases, this value slowly decreases (within 1%), and then, when it approaches 0 K, it drops sharply to 0 J·mol-at<sup>−1</sup>·K<sup>−1</sup>. To describe the set of the isostructural experimental data <em>C</em><sub>p</sub>(<em>T</em>) for diamond-like phases in solid state as a whole system, here we used a special multi-parameter family of functions. For each substance, the parameters are found by minimizing the discrepancy between the theoretical dependence <em>C</em><sub>p</sub>(<em>T</em>) and corresponding experimental data. The dependence of the heat capacities for elements of group IV (Si, Ge, α-Sn, diamond-like Pb, Fl) at fixed temperatures on Ln(<em>N</em>), where <em>N</em> is the atomic number or the demi sum of the atomic numbers of phases A<sup>II</sup>B<sup>VI</sup> or A<sup>III</sup>B<sup>V</sup>. In this case, ei","PeriodicalId":9436,"journal":{"name":"Calphad-computer Coupling of Phase Diagrams and Thermochemistry","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2024-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140344487","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Sn–Zr system was re-assessed thermodynamically. Gibbs free energies of the intermetallic compounds of this system were calculated by DFT phonon calculations which can give more reliable information owing to considering the contributions of lattice vibration and electric thermal excitation. Newly published valuable experimental data of liquidus, solidus and invariant reactions of this system were used for the first time in the optimization of the model parameters. It is shown that the previous thermodynamic models, where the Gibbs free energies of formation at different temperatures were replaced by energies of formation at 0 K, overestimated obviously the stability of all the compounds of this system. The thermodynamic model for the Sn–Zr system established in this work would give more solid prediction of phase structures and thermodynamic properties for materials containing Sn–Zr system.
{"title":"Thermodynamic reassessment of Sn–Zr system assisted by DFT phonon calculations","authors":"Jiaqing Peng , Jianyun Shen , Xuankai Feng , Zhuqing Cheng","doi":"10.1016/j.calphad.2024.102672","DOIUrl":"https://doi.org/10.1016/j.calphad.2024.102672","url":null,"abstract":"<div><p>The Sn–Zr system was re-assessed thermodynamically. Gibbs free energies of the intermetallic compounds of this system were calculated by DFT phonon calculations which can give more reliable information owing to considering the contributions of lattice vibration and electric thermal excitation. Newly published valuable experimental data of liquidus, solidus and invariant reactions of this system were used for the first time in the optimization of the model parameters. It is shown that the previous thermodynamic models, where the Gibbs free energies of formation at different temperatures were replaced by energies of formation at 0 K, overestimated obviously the stability of all the compounds of this system. The thermodynamic model for the Sn–Zr system established in this work would give more solid prediction of phase structures and thermodynamic properties for materials containing Sn–Zr system.</p></div>","PeriodicalId":9436,"journal":{"name":"Calphad-computer Coupling of Phase Diagrams and Thermochemistry","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2024-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140139120","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-03-15DOI: 10.1016/j.calphad.2024.102682
Yao-de Guo , Yohanes Hutabalian , Sinn-wen Chen
Co–Fe–Ge is an important material system for magnetic and catalyst applications. However, phase equilibria information of the Co–Fe–Ge ternary system is limited. Ternary Co–Fe–Ge alloys equilibrated at 950 °C were prepared. The microstructures, chemical compositions and crystal structure of each phase were determined. The phase equilibria isothermal section at 950 °C of the Co–Fe–Ge ternary system was then proposed. A continuous solid solution phase was formed between the Co5Ge3 and Fe5Ge3 phases and was labeled the β(Co,Fe)5Ge3 phase. There are five three-phase regions in the system at 950 °C. A wide α2 single-phase, and liquid phase regions with large composition ranges being confirmed at the Ge-poor and Ge-rich sides, respectively.
{"title":"Phase diagram of ternary Co–Fe–Ge system (I): Experimental","authors":"Yao-de Guo , Yohanes Hutabalian , Sinn-wen Chen","doi":"10.1016/j.calphad.2024.102682","DOIUrl":"https://doi.org/10.1016/j.calphad.2024.102682","url":null,"abstract":"<div><p>Co–Fe–Ge is an important material system for magnetic and catalyst applications. However, phase equilibria information of the Co–Fe–Ge ternary system is limited. Ternary Co–Fe–Ge alloys equilibrated at 950 °C were prepared. The microstructures, chemical compositions and crystal structure of each phase were determined. The phase equilibria isothermal section at 950 °C of the Co–Fe–Ge ternary system was then proposed. A continuous solid solution phase was formed between the Co<sub>5</sub>Ge<sub>3</sub> and Fe<sub>5</sub>Ge<sub>3</sub> phases and was labeled the β(Co,Fe)<sub>5</sub>Ge<sub>3</sub> phase. There are five three-phase regions in the system at 950 °C. A wide α<sub>2</sub> single-phase, and liquid phase regions with large composition ranges being confirmed at the Ge-poor and Ge-rich sides, respectively.</p></div>","PeriodicalId":9436,"journal":{"name":"Calphad-computer Coupling of Phase Diagrams and Thermochemistry","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2024-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140139119","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-03-14DOI: 10.1016/j.calphad.2024.102681
Dupei Ma , Yi ting Guo , Zhi Li , Jingxian Hu , Fucheng Yin , Yan Liu , Ye Liu
The partial phase equilibria of the Ni–Al−Dy ternary system have been systematically investigated via experimental analyses and thermodynamic modeling. Using the equilibrated alloy method, the 1150 °C and partial 800 °C isothermal sections of the Ni–Al−Dy ternary system and related Al–Dy binary system were constructed based on scanning electron microscopy, energy-dispersive spectroscopy and X-ray diffraction. Twelve three-phase regions were confirmed and four three-phase equilibria regions were speculated at 1150 °C, eight three-phase regions were determined at 800 °C, and five kinds of primary solidification regions, DyAl2, τ7, τ5, NiAl and Ni2Al3 were observed. A new ternary compound τ12 was discovered, which was stable at 800 °C and disappeared at 1150 °C, the τ1 phase was not stable at 800 and 1150 °C isothermal sections; the ternary compound τ11 was confirmed to be stable at 800 °C. In addition, the primary solidification phases were also identified, and five different primary solidification phases were found. Based on the experimental results available in this study and the literature, the thermodynamic modeling of the Ni–Al–Dy ternary system was obtained using the CALPHAD method. A set of self-consistent thermodynamic parameters for the Ni–Al–Dy ternary system was first obtained with a satisfactory agreement between the experimental and calculated results.
{"title":"Experimental investigation and thermodynamic modeling of the Al–Dy and Ni–Al−Dy systems","authors":"Dupei Ma , Yi ting Guo , Zhi Li , Jingxian Hu , Fucheng Yin , Yan Liu , Ye Liu","doi":"10.1016/j.calphad.2024.102681","DOIUrl":"https://doi.org/10.1016/j.calphad.2024.102681","url":null,"abstract":"<div><p>The partial phase equilibria of the Ni–Al−Dy ternary system have been systematically investigated via experimental analyses and thermodynamic modeling. Using the equilibrated alloy method, the 1150 °C and partial 800 °C isothermal sections of the Ni–Al−Dy ternary system and related Al–Dy binary system were constructed based on scanning electron microscopy, energy-dispersive spectroscopy and X-ray diffraction. Twelve three-phase regions were confirmed and four three-phase equilibria regions were speculated at 1150 °C, eight three-phase regions were determined at 800 °C, and five kinds of primary solidification regions, DyAl<sub>2</sub>, τ7, τ5, NiAl and Ni<sub>2</sub>Al<sub>3</sub> were observed. A new ternary compound τ12 was discovered, which was stable at 800 °C and disappeared at 1150 °C, the τ1 phase was not stable at 800 and 1150 °C isothermal sections; the ternary compound τ11 was confirmed to be stable at 800 °C. In addition, the primary solidification phases were also identified, and five different primary solidification phases were found. Based on the experimental results available in this study and the literature, the thermodynamic modeling of the Ni–Al–Dy ternary system was obtained using the CALPHAD method. A set of self-consistent thermodynamic parameters for the Ni–Al–Dy ternary system was first obtained with a satisfactory agreement between the experimental and calculated results.</p></div>","PeriodicalId":9436,"journal":{"name":"Calphad-computer Coupling of Phase Diagrams and Thermochemistry","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2024-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140133821","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-03-13DOI: 10.1016/j.calphad.2024.102668
Qian Wang , Wei He , Tonghan Yang , Yifei Bi , Yunxiang Yang , Chongjiang Li , Changzhong Liao
The phase diagram of the Gd-Mn-Ga ternary system is a very important tool for the exploration and development of rare earth Heusler alloys with excellent physical properties, such as magnetic properties, half-metallic properties, ferromagnetic shape memory effect, magnetocaloric effect, ect. In this study, the alloy samples were prepared using a vacuum arc melting furnace, and the 873 K isothermal section of the Gd-Mn-Ga (≤50 at.%Ga) ternary alloy phase diagram was determined by using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy spectrometry (EDS). The isothermal section consists of 22 single-phase regions, 44 two-phase regions, and 23 three-phase regions with the presence of 6 ternary compounds, GdMnGa, Gd2MnGa6, Gd2Mn15Ga2, Gd2Mn11Ga6, GdMn0.56Ga1.44, and GdMn0.37Ga1.63. The solid solubility ranges of Ga in β-Mn and Gd2Mn15Ga2 are 5.0–18.1 at.%Ga and 10.5–25.0 at.% Ga. The maximum solid solubility of Ga in α-Mn, GdMn12, and Gd6Mn23 are 2.0, 2.7, and 7.3 at.% Ga, respectively. The maximum solid solubility of Mn in GdGa2 is determined to be 13.1 at.% Mn.
{"title":"The isothermal section of the phase diagram of Gd-Mn-Ga (≤50 at.%Ga) ternary system at 873K","authors":"Qian Wang , Wei He , Tonghan Yang , Yifei Bi , Yunxiang Yang , Chongjiang Li , Changzhong Liao","doi":"10.1016/j.calphad.2024.102668","DOIUrl":"https://doi.org/10.1016/j.calphad.2024.102668","url":null,"abstract":"<div><p>The phase diagram of the Gd-Mn-Ga ternary system is a very important tool for the exploration and development of rare earth Heusler alloys with excellent physical properties, such as magnetic properties, half-metallic properties, ferromagnetic shape memory effect, magnetocaloric effect, ect. In this study, the alloy samples were prepared using a vacuum arc melting furnace, and the 873 K isothermal section of the Gd-Mn-Ga (≤50 at.%Ga) ternary alloy phase diagram was determined by using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy spectrometry (EDS). The isothermal section consists of 22 single-phase regions, 44 two-phase regions, and 23 three-phase regions with the presence of 6 ternary compounds, GdMnGa, Gd<sub>2</sub>MnGa<sub>6</sub>, Gd<sub>2</sub>Mn<sub>15</sub>Ga<sub>2</sub>, Gd<sub>2</sub>Mn<sub>11</sub>Ga<sub>6</sub>, GdMn<sub>0.56</sub>Ga<sub>1.44</sub>, and GdMn<sub>0.37</sub>Ga<sub>1.63</sub>. The solid solubility ranges of Ga in β-Mn and Gd<sub>2</sub>Mn<sub>15</sub>Ga<sub>2</sub> are 5.0–18.1 at.%Ga and 10.5–25.0 at.% Ga. The maximum solid solubility of Ga in α-Mn, GdMn<sub>12</sub>, and Gd<sub>6</sub>Mn<sub>23</sub> are 2.0, 2.7, and 7.3 at.% Ga, respectively. The maximum solid solubility of Mn in GdGa<sub>2</sub> is determined to be 13.1 at.% Mn.</p></div>","PeriodicalId":9436,"journal":{"name":"Calphad-computer Coupling of Phase Diagrams and Thermochemistry","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2024-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140122412","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-03-12DOI: 10.1016/j.calphad.2024.102683
Kuizhang Li , Guodong Fan , Weisen Zheng , Jingya Wang
Ti–Al–V alloys have received considerable attention owing to their excellent high-temperature mechanical properties. After conducting a critical review of the available experimental data for the ternary Ti–Al–V system, a thermodynamic assessment of the system was carried out over the entire composition and a wide temperature range utilizing the CALPHAD method. The extensive homogeneity ranges of the and phases were satisfactorily reproduced. Of particular significance was the first accurate description of the phase equilibria at 1573 K. The model parameters obtained in this study well represented the thermochemical properties and phase equilibria of the experimental data. Furthermore, the enthalpies of the widely used Ti alloy Ti–6Al–4V were reproduced using the thermodynamic description established in this study. Thus, this study provides a reliable basis for guiding the development and design of Ti–Al–V alloys.
{"title":"Thermodynamic modeling of the Ti–Al–V system over the entire composition and a wide temperature range","authors":"Kuizhang Li , Guodong Fan , Weisen Zheng , Jingya Wang","doi":"10.1016/j.calphad.2024.102683","DOIUrl":"https://doi.org/10.1016/j.calphad.2024.102683","url":null,"abstract":"<div><p>Ti–Al–V alloys have received considerable attention owing to their excellent high-temperature mechanical properties. After conducting a critical review of the available experimental data for the ternary Ti–Al–V system, a thermodynamic assessment of the system was carried out over the entire composition and a wide temperature range utilizing the CALPHAD method. The extensive homogeneity ranges of the <span><math><mrow><msub><mi>α</mi><mn>2</mn></msub></mrow></math></span> and <span><math><mrow><mi>γ</mi></mrow></math></span> phases were satisfactorily reproduced. Of particular significance was the first accurate description of the phase equilibria at 1573 K. The model parameters obtained in this study well represented the thermochemical properties and phase equilibria of the experimental data. Furthermore, the enthalpies of the widely used Ti alloy Ti–6Al–4V were reproduced using the thermodynamic description established in this study. Thus, this study provides a reliable basis for guiding the development and design of Ti–Al–V alloys.</p></div>","PeriodicalId":9436,"journal":{"name":"Calphad-computer Coupling of Phase Diagrams and Thermochemistry","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2024-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140113271","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-03-11DOI: 10.1016/j.calphad.2024.102671
Yongda Li , Gang Li , Ningyu Zhang , Guishang Pei , Yuxiao Xue , Xuewei Lv
Ca3TiFe2O8 (abbreviated as CTF), which is a significant mineral phase in the sinter of titanium-containing iron ore, was successfully prepared by solid-state reaction (calcined at 1553 K for 24 h) by using analytical reagents in this study. The metallurgical performance (melting performance and reduction behavior) was systemically characterized and the enthalpy change data of CTF was tested. The results show that softening temperature, melting temperature, and flowing temperature of CTF were 1691 K, 1734 K, and 1753 K, respectively. The non-isothermal reduction results revealed that CTF was reduced to Fe, CaO, and perovskite in a single step, and the CTF reduction was completed when the temperature reached 1423 K. The results of isothermal reduction shows that the reduction degree of CTF was 89% when reduced at 1173 K for 79.2 min, and the order of reduction performance was Fe2O3 > Fe3O4 > CaO∙2Fe2O3 > CaO∙Fe2O3> Ca3TiFe2O8> 2CaO∙Fe2O3> Ca3Fe2Si1.58Ti1.42O12.
{"title":"Metallurgical performance of Ca3TiFe2O8","authors":"Yongda Li , Gang Li , Ningyu Zhang , Guishang Pei , Yuxiao Xue , Xuewei Lv","doi":"10.1016/j.calphad.2024.102671","DOIUrl":"https://doi.org/10.1016/j.calphad.2024.102671","url":null,"abstract":"<div><p>Ca<sub>3</sub>TiFe<sub>2</sub>O<sub>8</sub> (abbreviated as CTF), which is a significant mineral phase in the sinter of titanium-containing iron ore, was successfully prepared by solid-state reaction (calcined at 1553 K for 24 h) by using analytical reagents in this study. The metallurgical performance (melting performance and reduction behavior) was systemically characterized and the enthalpy change data of CTF was tested. The results show that softening temperature, melting temperature, and flowing temperature of CTF were 1691 K, 1734 K, and 1753 K, respectively. The non-isothermal reduction results revealed that CTF was reduced to Fe, CaO, and perovskite in a single step, and the CTF reduction was completed when the temperature reached 1423 K. The results of isothermal reduction shows that the reduction degree of CTF was 89% when reduced at 1173 K for 79.2 min, and the order of reduction performance was Fe<sub>2</sub>O<sub>3</sub> > Fe<sub>3</sub>O<sub>4</sub> > CaO∙2Fe<sub>2</sub>O<sub>3</sub> > CaO∙Fe<sub>2</sub>O<sub>3</sub>> Ca<sub>3</sub>TiFe<sub>2</sub>O<sub>8</sub>> 2CaO∙Fe<sub>2</sub>O<sub>3</sub>> Ca<sub>3</sub>Fe<sub>2</sub>Si<sub>1.58</sub>Ti<sub>1.42</sub>O<sub>12</sub>.</p></div>","PeriodicalId":9436,"journal":{"name":"Calphad-computer Coupling of Phase Diagrams and Thermochemistry","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2024-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140103539","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-03-08DOI: 10.1016/j.calphad.2024.102680
Yifang Ouyang , Meiling Xiong , Kuixin Lin , Yulu Zhou , Hongmei Chen , Xiaoma Tao , Qing Peng , Yong Du
A novel second-nearest-neighbor (2NN) modified embedded atom method (MEAM) potential for Zr–C system has been developed. The lattice constants, formation enthalpy, mechanical properties of stoichiometric ZrC have been reproduced. The melting point from the new 2NN-MEAM potential is 3436 K, which is coincident with the experimental melting point, ∼3530 K. The properties of sub-stoichiometric ZrCx with ordered or disordered carbon vacancy have also been examined with the new potential. The results for ordered sub-stoichiometric ZrCx agree well with the experimental data and/or first-principles calculations. The lattice parameter, elastic properties, thermodynamic properties change with the C/Zr ratio have been studied. The predicted relationships between the properties versus C/Zr ratio coincide with available experimental results. These results indicate the present 2NN-MEAM potential is suitable for atomic scale simulation of ZrC.
{"title":"The effect of carbon vacancy on the properties of ZrC by MEAM potentials","authors":"Yifang Ouyang , Meiling Xiong , Kuixin Lin , Yulu Zhou , Hongmei Chen , Xiaoma Tao , Qing Peng , Yong Du","doi":"10.1016/j.calphad.2024.102680","DOIUrl":"https://doi.org/10.1016/j.calphad.2024.102680","url":null,"abstract":"<div><p>A novel second-nearest-neighbor (2NN) modified embedded atom method (MEAM) potential for Zr–C system has been developed. The lattice constants, formation enthalpy, mechanical properties of stoichiometric ZrC have been reproduced. The melting point from the new 2NN-MEAM potential is 3436 K, which is coincident with the experimental melting point, ∼3530 K. The properties of sub-stoichiometric ZrC<sub><em>x</em></sub> with ordered or disordered carbon vacancy have also been examined with the new potential. The results for ordered sub-stoichiometric ZrC<sub><em>x</em></sub> agree well with the experimental data and/or first-principles calculations. The lattice parameter, elastic properties, thermodynamic properties change with the C/Zr ratio have been studied. The predicted relationships between the properties versus C/Zr ratio coincide with available experimental results. These results indicate the present 2NN-MEAM potential is suitable for atomic scale simulation of ZrC.</p></div>","PeriodicalId":9436,"journal":{"name":"Calphad-computer Coupling of Phase Diagrams and Thermochemistry","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2024-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140062070","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2024-03-01DOI: 10.1016/j.calphad.2024.102669
Antonio Augusto Araujo Pinto da Silva , Pedro Pires Ferreira , Thiago Trevizam Dorini , Gilberto Carvalho Coelho , Carlos Angelo Nunes , Luiz Tadeu Fernandes Eleno
The Ta–Ge system was thermodynamically modeled for the first time using the CALPHAD method incorporating both literature-derived phase equilibria data and new enthalpy of formation values for the intermetallic compounds. Density Functional Theory (DFT) calculations were employed to accurately determine enthalpy of formation values for key Ta–Ge compounds. The stable intermetallic phases (i.e., αTa3Ge, βTa3Ge, βTa5Ge3, and TaGe2) were described as stoichiometric phases while the Liquid (L), Ta-rich solid solution (BCC-A2), and Ge-rich solid solution (Diamond-A4) were modeled as solution phases using the Compound Energy Formalism. Excess terms were described by the Redlich-Kister polynomials. The present thermodynamic model accurately describes phase equilibria and thermodynamic data, providing a reliable guide for designing alloys containing Ta and Ge.
利用 CALPHAD 方法首次对 Ta-Ge 体系进行了热力学建模,其中包含了从文献中获得的相平衡数据和金属间化合物的新形成焓值。密度泛函理论(DFT)计算准确地确定了主要 Ta-Ge 化合物的形成焓值。稳定的金属间化合物相(即 αTa3Ge、βTa3Ge、βTa5Ge3 和 TaGe2)被描述为化学计量相,而液体(L)、富 Ta 固溶体(BCC-A2)和富 Ge 固溶体(Diamond-A4)则使用化合物能量形式主义被模拟为溶液相。过剩项由 Redlich-Kister 多项式描述。本热力学模型准确地描述了相平衡和热力学数据,为设计含有 Ta 和 Ge 的合金提供了可靠的指导。
{"title":"Thermodynamic assessment of the Ta–Ge system supported by ab initio calculations","authors":"Antonio Augusto Araujo Pinto da Silva , Pedro Pires Ferreira , Thiago Trevizam Dorini , Gilberto Carvalho Coelho , Carlos Angelo Nunes , Luiz Tadeu Fernandes Eleno","doi":"10.1016/j.calphad.2024.102669","DOIUrl":"https://doi.org/10.1016/j.calphad.2024.102669","url":null,"abstract":"<div><p>The Ta–Ge system was thermodynamically modeled for the first time using the CALPHAD method incorporating both literature-derived phase equilibria data and new enthalpy of formation values for the intermetallic compounds. Density Functional Theory (DFT) calculations were employed to accurately determine enthalpy of formation values for key Ta–Ge compounds. The stable intermetallic phases (i.e., αTa<sub>3</sub>Ge, βTa<sub>3</sub>Ge, βTa<sub>5</sub>Ge<sub>3</sub>, and TaGe<sub>2</sub>) were described as stoichiometric phases while the Liquid (L), Ta-rich solid solution (BCC-A2), and Ge-rich solid solution (Diamond-A4) were modeled as solution phases using the Compound Energy Formalism. Excess terms were described by the Redlich-Kister polynomials. The present thermodynamic model accurately describes phase equilibria and thermodynamic data, providing a reliable guide for designing alloys containing Ta and Ge.</p></div>","PeriodicalId":9436,"journal":{"name":"Calphad-computer Coupling of Phase Diagrams and Thermochemistry","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139992707","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}