Pub Date : 2025-12-15DOI: 10.1016/j.calphad.2025.102905
Huixin Liu , Yue Zhang , Shiyi Wen , Yuling Liu , Changfa Du , Yong Du
The critique by Ling et al. (2025) regarding the interdiffusivities reported in our prior study (Liu et al., 2023) is addressed herein. Our original work contained two clerical errors wherein the labels for the diffusion couples at the two temperatures in Table 3 were swapped, and the hollow/solid symbols in Fig. 4 were reversed. We emphasize that these were labeling and formatting errors which do not affect the analysis and conclusions in our previous work. This work rectifies those oversights. Furthermore, while Ling et al. (2025) employed 11 interaction parameters to assess atomic mobilities in the fcc Co-Ni-Si phase, our model only utilizes 3 cross-binary parameters. Quantitative comparison the interdiffusivities demonstrates that our model achieves a mean squared error (MSE) of 0.0256, that is lower than 0.0706 reported by Ling et al., validating the effectiveness of our simplified parametric approach.
{"title":"Reply to comment on the paper “Thermodynamic, diffusion and precipitation behaviors in Cu-Ni-Si-Co alloys: Modeling and experimental validation”","authors":"Huixin Liu , Yue Zhang , Shiyi Wen , Yuling Liu , Changfa Du , Yong Du","doi":"10.1016/j.calphad.2025.102905","DOIUrl":"10.1016/j.calphad.2025.102905","url":null,"abstract":"<div><div>The critique by Ling et al. (2025) regarding the interdiffusivities reported in our prior study (Liu et al., 2023) is addressed herein. Our original work contained two clerical errors wherein the labels for the diffusion couples at the two temperatures in Table 3 were swapped, and the hollow/solid symbols in Fig. 4 were reversed. We emphasize that these were labeling and formatting errors which do not affect the analysis and conclusions in our previous work. This work rectifies those oversights. Furthermore, while Ling et al. (2025) employed 11 interaction parameters to assess atomic mobilities in the fcc Co-Ni-Si phase, our model only utilizes 3 cross-binary parameters. Quantitative comparison the interdiffusivities demonstrates that our model achieves a mean squared error (MSE) of 0.0256, that is lower than 0.0706 reported by Ling et al., validating the effectiveness of our simplified parametric approach.</div></div>","PeriodicalId":9436,"journal":{"name":"Calphad-computer Coupling of Phase Diagrams and Thermochemistry","volume":"92 ","pages":"Article 102905"},"PeriodicalIF":1.9,"publicationDate":"2025-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145788121","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 : 2025-12-13DOI: 10.1016/j.calphad.2025.102911
Yuanlu Zhou , Chenyang Zhou , Jiaxin Cui , Weibin Xie , Huiming Chen , Hang Wang
The microstructural and compositional analyses were carried out for 30 ternary equilibrated alloys to investigate the Al–Co–Ti phase equilibria at 1173 K. 14 three-phase equilibrium regions with 3 ternary compounds were confirmed at this temperature in the Al–Co–Ti system. Subsequently, the thermodynamic modeling of this system was conducted via the CALculation of PHAse Diagram (CALPHAD) method based on the experimental data from this study and the literature. The substitutional model was utilized for assessing the disordered solution phases Liquid, A1 (Al and γCo), A2 (βTi) and A3 (αCo and αTi). Both A1-L12 and A2-B2 order-disorder transitions were modeled simultaneously utilizing a single Gibbs energy function. The binary intermetallic phases Co2Ti(h), Co2Ti(c) and CoTi2 were described as (Al,Co,Ti)2(Al,Co,Ti)1, (Al,Co,Ti)2(Al,Co,Ti)1 and Co1(Al,Ti)2, while the others with the limited ternary solubility were treated as binary compounds. The ternary intermetallic phases τ1, τ2 and τ3 were modeled in the form of Al0.66Co0.05Ti0.29, (Al,Ti)16Ti6(Co,Ti)7 and (Al,Ti)1Co2(Al,Co,Ti)1. A set of self-consistent thermodynamic parameters for this system has been provided, and the majority of the experimental data can be reproduced well with the parameters.
{"title":"Experimental phase equilibria and thermodynamic modeling of the Al–Co–Ti ternary system","authors":"Yuanlu Zhou , Chenyang Zhou , Jiaxin Cui , Weibin Xie , Huiming Chen , Hang Wang","doi":"10.1016/j.calphad.2025.102911","DOIUrl":"10.1016/j.calphad.2025.102911","url":null,"abstract":"<div><div>The microstructural and compositional analyses were carried out for 30 ternary equilibrated alloys to investigate the Al–Co–Ti phase equilibria at 1173 K. 14 three-phase equilibrium regions with 3 ternary compounds were confirmed at this temperature in the Al–Co–Ti system. Subsequently, the thermodynamic modeling of this system was conducted via the CALculation of PHAse Diagram (CALPHAD) method based on the experimental data from this study and the literature. The substitutional model was utilized for assessing the disordered solution phases Liquid, A1 (Al and γCo), A2 (βTi) and A3 (αCo and αTi). Both A1-L1<sub>2</sub> and A2-B2 order-disorder transitions were modeled simultaneously utilizing a single Gibbs energy function. The binary intermetallic phases Co<sub>2</sub>Ti(h), Co<sub>2</sub>Ti(c) and CoTi<sub>2</sub> were described as (Al,Co,Ti)<sub>2</sub>(Al,Co,Ti)<sub>1</sub>, (Al,Co,Ti)<sub>2</sub>(Al,Co,Ti)<sub>1</sub> and Co<sub>1</sub>(Al,Ti)<sub>2</sub>, while the others with the limited ternary solubility were treated as binary compounds. The ternary intermetallic phases τ<sub>1</sub>, τ<sub>2</sub> and τ<sub>3</sub> were modeled in the form of Al<sub>0.66</sub>Co<sub>0.05</sub>Ti<sub>0.29</sub>, (Al,Ti)<sub>16</sub>Ti<sub>6</sub>(Co,Ti)<sub>7</sub> and (Al,Ti)<sub>1</sub>Co<sub>2</sub>(Al,Co,Ti)<sub>1</sub>. A set of self-consistent thermodynamic parameters for this system has been provided, and the majority of the experimental data can be reproduced well with the parameters.</div></div>","PeriodicalId":9436,"journal":{"name":"Calphad-computer Coupling of Phase Diagrams and Thermochemistry","volume":"92 ","pages":"Article 102911"},"PeriodicalIF":1.9,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145735889","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 : 2025-12-11DOI: 10.1016/j.calphad.2025.102908
Zhongwen Shi , Wei Liu , Genfeng Shang , Xiao-Gang Lu
In the present work, the enthalpies of mixing and the magnetic moments of the solid solutions in the Ni-Ru and Co-Ru systems were determined by first-principles calculations based on density functional theory (DFT). The phase relationships of the Ni-Co-Ru and its binary subsystems were determined by equilibrated alloys and diffusion couples. Based on the available data, a thermodynamic assessment of the Ni-Co-Ru system was performed using the CALPHAD method. The thermodynamic description reproduces the phase diagram data well. Subsequently, the atomic mobilities of the Ni-Ru and Co-Ru systems were evaluated using the experimental data and first-principles calculations from the literature. The interdiffusion coefficients of the fcc phase at the Co-rich corner in the Ni-Co-Ru system at 1273 K and 1473 K were extracted from the composition profiles of diffusion couples. Based on the experimental diffusion data and the present thermodynamic parameters, the atomic mobilities of the fcc Ni-Co-Ru system were assessed, and comprehensive comparisons prove the consistency between the present assessments and the experiments.
{"title":"Thermodynamic assessment of the Ni-Co-Ru system and diffusion study of its fcc phase","authors":"Zhongwen Shi , Wei Liu , Genfeng Shang , Xiao-Gang Lu","doi":"10.1016/j.calphad.2025.102908","DOIUrl":"10.1016/j.calphad.2025.102908","url":null,"abstract":"<div><div>In the present work, the enthalpies of mixing and the magnetic moments of the solid solutions in the Ni-Ru and Co-Ru systems were determined by first-principles calculations based on density functional theory (DFT). The phase relationships of the Ni-Co-Ru and its binary subsystems were determined by equilibrated alloys and diffusion couples. Based on the available data, a thermodynamic assessment of the Ni-Co-Ru system was performed using the CALPHAD method. The thermodynamic description reproduces the phase diagram data well. Subsequently, the atomic mobilities of the Ni-Ru and Co-Ru systems were evaluated using the experimental data and first-principles calculations from the literature. The interdiffusion coefficients of the fcc phase at the Co-rich corner in the Ni-Co-Ru system at 1273 K and 1473 K were extracted from the composition profiles of diffusion couples. Based on the experimental diffusion data and the present thermodynamic parameters, the atomic mobilities of the fcc Ni-Co-Ru system were assessed, and comprehensive comparisons prove the consistency between the present assessments and the experiments.</div></div>","PeriodicalId":9436,"journal":{"name":"Calphad-computer Coupling of Phase Diagrams and Thermochemistry","volume":"92 ","pages":"Article 102908"},"PeriodicalIF":1.9,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145735890","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 : 2025-12-10DOI: 10.1016/j.calphad.2025.102910
Lideng Ye , Chenbo Li , Ziqian Wang, Boyan Jiang, Hong Chen, Yaodong Yang, Ligang Zhang, Libin Liu
The phase equilibria in the Al-Fe-W ternary system at 873K and 1073K were experimentally investigated by scanning electron microscope (SEM), X-ray diffraction (XRD) and electron probe microanalysis (EPMA). In the isothermal sections at 873 K and 1073 K, six three-phase regions and three two-phase regions at 873 K, and four three-phase regions and four two-phase regions at 1073 K, respectively, were confirmed. And their phase region boundaries were precisely determined. No ternary compounds were observed. At the same time, the solubility of the third element in the Fe7W6, Fe2W, Al4W, Al5W, Al12W, Al2Fe, Al5Fe2 and Al13Fe4 compounds within the Al-Fe-W ternary system was also obtained. According to the measured experimental data of the Al-Fe-W ternary system and the related binary systems, the Al-Fe-W ternary system was optimized using the CALPHAD (CALculation of PHAse Diagrams) method. A new thermodynamic database for the Al-Fe-W ternary system was developed, and the calculated results showed good agreement with the experimental phase equilibrium data.
{"title":"Experimental investigation and thermodynamic assessment of the Al-Fe-W Phase Diagram","authors":"Lideng Ye , Chenbo Li , Ziqian Wang, Boyan Jiang, Hong Chen, Yaodong Yang, Ligang Zhang, Libin Liu","doi":"10.1016/j.calphad.2025.102910","DOIUrl":"10.1016/j.calphad.2025.102910","url":null,"abstract":"<div><div>The phase equilibria in the Al-Fe-W ternary system at 873K and 1073K were experimentally investigated by scanning electron microscope (SEM), X-ray diffraction (XRD) and electron probe microanalysis (EPMA). In the isothermal sections at 873 K and 1073 K, six three-phase regions and three two-phase regions at 873 K, and four three-phase regions and four two-phase regions at 1073 K, respectively, were confirmed. And their phase region boundaries were precisely determined. No ternary compounds were observed. At the same time, the solubility of the third element in the Fe<sub>7</sub>W<sub>6</sub>, Fe<sub>2</sub>W, Al<sub>4</sub>W, Al<sub>5</sub>W, Al<sub>12</sub>W, Al<sub>2</sub>Fe, Al<sub>5</sub>Fe<sub>2</sub> and Al<sub>13</sub>Fe<sub>4</sub> compounds within the Al-Fe-W ternary system was also obtained. According to the measured experimental data of the Al-Fe-W ternary system and the related binary systems, the Al-Fe-W ternary system was optimized using the CALPHAD (CALculation of PHAse Diagrams) method. A new thermodynamic database for the Al-Fe-W ternary system was developed, and the calculated results showed good agreement with the experimental phase equilibrium data.</div></div>","PeriodicalId":9436,"journal":{"name":"Calphad-computer Coupling of Phase Diagrams and Thermochemistry","volume":"92 ","pages":"Article 102910"},"PeriodicalIF":1.9,"publicationDate":"2025-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145735891","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 : 2025-12-08DOI: 10.1016/j.calphad.2025.102898
Yong Li , Keming Mao , Shan Chen , Chenchong Wang , Wei Xu
Bainite is a crucial microstructure in steel, and its transformation kinetics plays a key role in microstructural control and property optimisation. Conventionally, bainite formation initiates at austenite grain boundaries and continues through autocatalytic nucleation at the newly formed bainitic ferrite/austenite interfaces. However, recent studies have revealed that the presence of martensite prior to the austenite-to-bainite transformation can significantly alter the transformation behaviour. In this work, within the framework of the displacive mechanism, a new isothermal kinetic model is proposed by introducing the catalytic effect of martensite/austenite interfaces to characterise the influence of pre-existing martensite on bainite transformation in high-Si steels. The model was validated through dilatometry experiments performed on two Fe-C-Mn-Si steels with different Mn contents, under both above-Ms and below-Ms temperature conditions. The results demonstrate that bainite transformation exhibits an incubation period above Ms, whereas below Ms, the pre-existing martensite markedly shortens the incubation stage and accelerates the initial transformation rate. There is a high level of agreement between the model predictions and the experimental observations, successfully capturing the key features of the transformation behaviour, including transformation rate, incubation period, final fraction, and the incomplete transformation phenomenon.
{"title":"Modelling the kinetics of bainite transformation with pre-existing martensite in High-Si steels","authors":"Yong Li , Keming Mao , Shan Chen , Chenchong Wang , Wei Xu","doi":"10.1016/j.calphad.2025.102898","DOIUrl":"10.1016/j.calphad.2025.102898","url":null,"abstract":"<div><div>Bainite is a crucial microstructure in steel, and its transformation kinetics plays a key role in microstructural control and property optimisation. Conventionally, bainite formation initiates at austenite grain boundaries and continues through autocatalytic nucleation at the newly formed bainitic ferrite/austenite interfaces. However, recent studies have revealed that the presence of martensite prior to the austenite-to-bainite transformation can significantly alter the transformation behaviour. In this work, within the framework of the displacive mechanism, a new isothermal kinetic model is proposed by introducing the catalytic effect of martensite/austenite interfaces to characterise the influence of pre-existing martensite on bainite transformation in high-Si steels. The model was validated through dilatometry experiments performed on two Fe-C-Mn-Si steels with different Mn contents, under both above-Ms and below-Ms temperature conditions. The results demonstrate that bainite transformation exhibits an incubation period above Ms, whereas below Ms, the pre-existing martensite markedly shortens the incubation stage and accelerates the initial transformation rate. There is a high level of agreement between the model predictions and the experimental observations, successfully capturing the key features of the transformation behaviour, including transformation rate, incubation period, final fraction, and the incomplete transformation phenomenon.</div></div>","PeriodicalId":9436,"journal":{"name":"Calphad-computer Coupling of Phase Diagrams and Thermochemistry","volume":"92 ","pages":"Article 102898"},"PeriodicalIF":1.9,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145693225","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 : 2025-12-01DOI: 10.1016/j.calphad.2025.102897
Júlio César Pereira dos Santos , Sean Griesemer , Ursula R. Kattner , Chris Wolverton , Carelyn E. Campbell
The Effective Bond Energy Formalism (EBEF) is used in the present work to describe the mu (μ) and sigma (σ) phases in the Co-Cr-Ni-W system. This represents the first time that: i) μ is described using the EBEF, and ii) two Topologically Closed-Packed (TCP) phases are simultaneously described with the EBEF. Both phases are described with thermodynamic models that are more consistent with their real crystallography and their formation energies are determined using new Density Functional Theory (DFT) calculations. The good agreement obtained between the calculated phase diagrams and the experimental results indicates once again that the EBEF is suitable to describe complex TCP phases. Furthermore, the implementation of the EBEF led to a significant reduction in the number of adjustable/ternary parameters needed, when the present thermodynamic assessment is compared to descriptions available in the literature.
{"title":"Applying the Effective Bond Energy Formalism (EBEF) to describe the mu (μ) and sigma (σ) phases in the Co-Cr-Ni-W system","authors":"Júlio César Pereira dos Santos , Sean Griesemer , Ursula R. Kattner , Chris Wolverton , Carelyn E. Campbell","doi":"10.1016/j.calphad.2025.102897","DOIUrl":"10.1016/j.calphad.2025.102897","url":null,"abstract":"<div><div>The Effective Bond Energy Formalism (EBEF) is used in the present work to describe the mu (μ) and sigma (σ) phases in the Co-Cr-Ni-W system. This represents the first time that: i) μ is described using the EBEF, and ii) two Topologically Closed-Packed (TCP) phases are simultaneously described with the EBEF. Both phases are described with thermodynamic models that are more consistent with their real crystallography and their formation energies are determined using new Density Functional Theory (DFT) calculations. The good agreement obtained between the calculated phase diagrams and the experimental results indicates once again that the EBEF is suitable to describe complex TCP phases. Furthermore, the implementation of the EBEF led to a significant reduction in the number of adjustable/ternary parameters needed, when the present thermodynamic assessment is compared to descriptions available in the literature.</div></div>","PeriodicalId":9436,"journal":{"name":"Calphad-computer Coupling of Phase Diagrams and Thermochemistry","volume":"91 ","pages":"Article 102897"},"PeriodicalIF":1.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145680796","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 development of advanced thermodynamic descriptions for pure elements is essential for accurate modelling of multicomponent systems. The third-generation Calphad descriptions incorporate physical effects such as electronic, vibrational and anharmonic contributions. In this study, we have developed a third-generation Calphad description for pure niobium (Nb). Thermodynamic properties of key phases — bcc, fcc, hcp and liquid — are presented for pure Nb. The vibrational contribution to the heat capacity of the solid phases has been modelled with the Einstein model, and the liquid phase has been modelled with the two-state model. In addition, the modelling of unstable phases has been extensively analysed. The traditional Calphad approach is evaluated and compared with the ab initio approach, which has a stronger theoretical basis. The 0 K energies of the unstable phases, fcc and hcp, have been selected from ab initio calculations using the inflection–detection method. Good agreement has been achieved with the selected experimental and ab initio data.
{"title":"A third-generation Calphad description of pure Nb","authors":"Felicia Larsson , Lorenzo Fenocchio , Qing Chen , Gabriele Cacciamani , Malin Selleby","doi":"10.1016/j.calphad.2025.102894","DOIUrl":"10.1016/j.calphad.2025.102894","url":null,"abstract":"<div><div>The development of advanced thermodynamic descriptions for pure elements is essential for accurate modelling of multicomponent systems. The third-generation Calphad descriptions incorporate physical effects such as electronic, vibrational and anharmonic contributions. In this study, we have developed a third-generation Calphad description for pure niobium (Nb). Thermodynamic properties of key phases — bcc, fcc, hcp and liquid — are presented for pure Nb. The vibrational contribution to the heat capacity of the solid phases has been modelled with the Einstein model, and the liquid phase has been modelled with the two-state model. In addition, the modelling of unstable phases has been extensively analysed. The traditional Calphad approach is evaluated and compared with the ab initio approach, which has a stronger theoretical basis. The 0 K energies of the unstable phases, fcc and hcp, have been selected from ab initio calculations using the inflection–detection method. Good agreement has been achieved with the selected experimental and ab initio data.</div></div>","PeriodicalId":9436,"journal":{"name":"Calphad-computer Coupling of Phase Diagrams and Thermochemistry","volume":"91 ","pages":"Article 102894"},"PeriodicalIF":1.9,"publicationDate":"2025-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145568519","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 : 2025-11-10DOI: 10.1016/j.calphad.2025.102896
Daiman Zhu , Xiaohan Liu , Nele Moelans , Yongli Li
The Al-Ni-Gd ternary system, a potential candidate as metallic glass alloy, has been thermodynamically assessed by CALPHAD approach based on available experimental data and new DFT calculations. For all phases in the system, the expressions of Gibbs energies are proposed and the related parameters are optimized, after the systematic integration of the literature reported descriptions of the Al-Ni, Al-Gd and Ni-Gd binary subsystems. DFT calculations are carried out in order to determine formation enthalpies of the stable and metastable compounds. For the isothermal sections at 1073 and 773 K, the comparisons between the results of computations with the data of experiments indicate that the proposed thermodynamic description can finely reproduce the phase equilibria of the Al-Ni-Gd ternary system. In addition, the liquidus projection, together with iso-pleth sections at 3 at.% Gd, 12 at.% Gd, 3 at.% Ni, and 10 at.% Ni, have been calculated to predict the metallic glass region within the Al-Ni-Gd ternary system, which aligns well with reported literature data. A set of self-consistent thermodynamic parameters has thus been derived for the Al-Ni-Gd ternary system, which contributes to the comprehensive development of a thermodynamic database for Al-based alloys.
{"title":"Thermodynamic modelling and metallic glass region prediction for the Al-Ni-Gd ternary system","authors":"Daiman Zhu , Xiaohan Liu , Nele Moelans , Yongli Li","doi":"10.1016/j.calphad.2025.102896","DOIUrl":"10.1016/j.calphad.2025.102896","url":null,"abstract":"<div><div>The Al-Ni-Gd ternary system, a potential candidate as metallic glass alloy, has been thermodynamically assessed by CALPHAD approach based on available experimental data and new DFT calculations. For all phases in the system, the expressions of Gibbs energies are proposed and the related parameters are optimized, after the systematic integration of the literature reported descriptions of the Al-Ni, Al-Gd and Ni-Gd binary subsystems. DFT calculations are carried out in order to determine formation enthalpies of the stable and metastable compounds. For the isothermal sections at 1073 and 773 K, the comparisons between the results of computations with the data of experiments indicate that the proposed thermodynamic description can finely reproduce the phase equilibria of the Al-Ni-Gd ternary system. In addition, the liquidus projection, together with iso-pleth sections at 3 at.% Gd, 12 at.% Gd, 3 at.% Ni, and 10 at.% Ni, have been calculated to predict the metallic glass region within the Al-Ni-Gd ternary system, which aligns well with reported literature data. A set of self-consistent thermodynamic parameters has thus been derived for the Al-Ni-Gd ternary system, which contributes to the comprehensive development of a thermodynamic database for Al-based alloys.</div></div>","PeriodicalId":9436,"journal":{"name":"Calphad-computer Coupling of Phase Diagrams and Thermochemistry","volume":"91 ","pages":"Article 102896"},"PeriodicalIF":1.9,"publicationDate":"2025-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145516660","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 : 2025-11-08DOI: 10.1016/j.calphad.2025.102893
Weiyin Huang , Wei Yang , Xiaozhong Huang , Zhi Li , Xinming Wang , Peisheng Wang , Shuhong Liu , Yong Du
Phase equilibria of the Fe-Dy-Y system are essential for developing Dy/Y substituted Nd-Fe-B permanent magnets. In this work, the isothermal phase diagrams at 973 K and 773 K of the system were investigated by electron probe microanalysis (EPMA) and X-ray diffraction (XRD). Given the exceptionally slow diffusion kinetics of rare earth elements, achieving thermodynamic equilibrium necessitated prolonged annealing times of up to 130 days at 773 K, as confirmed by microstructural evolution studies. Key findings include the absence of ternary compounds and the formation of continuous solid solutions across the Dy-Y join for all binary intermetallic phases, except the Fe17RE2 phase. The liquidus and solidus of selected alloys were analyzed by differential scanning calorimetry (DSC). The CALPHAD assessment of the Fe-Dy-Y system was performed, which is consistent with the experimental data.
{"title":"Experimental determination and thermodynamic assessment of the Fe-Dy-Y system","authors":"Weiyin Huang , Wei Yang , Xiaozhong Huang , Zhi Li , Xinming Wang , Peisheng Wang , Shuhong Liu , Yong Du","doi":"10.1016/j.calphad.2025.102893","DOIUrl":"10.1016/j.calphad.2025.102893","url":null,"abstract":"<div><div>Phase equilibria of the Fe-Dy-Y system are essential for developing Dy/Y substituted Nd-Fe-B permanent magnets. In this work, the isothermal phase diagrams at 973 K and 773 K of the system were investigated by electron probe microanalysis (EPMA) and X-ray diffraction (XRD). Given the exceptionally slow diffusion kinetics of rare earth elements, achieving thermodynamic equilibrium necessitated prolonged annealing times of up to 130 days at 773 K, as confirmed by microstructural evolution studies. Key findings include the absence of ternary compounds and the formation of continuous solid solutions across the Dy-Y join for all binary intermetallic phases, except the Fe<sub>17</sub>RE<sub>2</sub> phase. The liquidus and solidus of selected alloys were analyzed by differential scanning calorimetry (DSC). The CALPHAD assessment of the Fe-Dy-Y system was performed, which is consistent with the experimental data.</div></div>","PeriodicalId":9436,"journal":{"name":"Calphad-computer Coupling of Phase Diagrams and Thermochemistry","volume":"91 ","pages":"Article 102893"},"PeriodicalIF":1.9,"publicationDate":"2025-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145462610","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 : 2025-11-08DOI: 10.1016/j.calphad.2025.102895
Kangying Li, Ruihen Zhu, Fengxiang Zhao, Chengbo Li, Tonghan Yang
The phase equilibria in the Ho-Fe-Ti ternary system at 1173 K were investigated using X-ray diffraction (XRD) and scanning electron microscope (SEM). A new ternary compound, HoFe9Ti2, was identified under the studied conditions. In total, one ternary and six binary compounds were confirmed, namely HoFe11Ti, TiFe2, TiFe, Fe17Ho2, Fe23Ho6, Fe3Ho, Fe2Ho. The maximum solid solubility of Ti in Fe17Ho2, Fe23Ho6, Fe3Ho, and Fe2Ho was determined to be 4.2, 1.3, 5.4, and 7.3 at.%, respectively, while the maximum solid solubility of Ho in TiFe2 was 0.9 at.%. Structural characterization of the HoFe9Ti2 compound showed that this phase crystallizes in the tetragonal P4/mbm space group. The HoFe9Ti2 phase exhibits lattice parameters of a = b = 0.82113(7) nm and c = 0.48057(6) nm. Structural characterization of the HoFe11Ti compound showed that this phase crystallizes in the tetragonal I4/mmm space group. The HoFe11Ti phase exhibits lattice parameters of a = b = 0.84911(7) nm and c = 0.47830(1) nm.
采用x射线衍射（XRD）和扫描电镜（SEM）研究了1173 K下Ho-Fe-Ti三元体系的相平衡。在此条件下，发现了一种新的三元化合物HoFe9Ti2。共鉴定出1个三元化合物和6个二元化合物，分别为HoFe11Ti、TiFe2、TiFe、Fe17Ho2、Fe23Ho6、Fe3Ho、Fe2Ho。测定Ti在Fe17Ho2、Fe23Ho6、Fe3Ho和Fe2Ho中的最大固溶度分别为4.2、1.3、5.4和7.3 at。而Ho在TiFe2中的最大固溶度为0.9 at.%。HoFe9Ti2化合物的结构表征表明，该相在四方P4/mbm空间群中结晶。HoFe9Ti2相的晶格参数为a = b = 0.82113(7) nm和c = 0.48057(6) nm，结构表征表明该相在I4/mmm四边形空间群中结晶。HoFe11Ti相的晶格参数为a = b = 0.84911(7) nm和c = 0.47830(1) nm。
{"title":"The phase equilibria in the Ho-Fe-Ti ternary system at 1173 K","authors":"Kangying Li, Ruihen Zhu, Fengxiang Zhao, Chengbo Li, Tonghan Yang","doi":"10.1016/j.calphad.2025.102895","DOIUrl":"10.1016/j.calphad.2025.102895","url":null,"abstract":"<div><div>The phase equilibria in the Ho-Fe-Ti ternary system at 1173 K were investigated using X-ray diffraction (XRD) and scanning electron microscope (SEM). A new ternary compound, HoFe<sub>9</sub>Ti<sub>2</sub>, was identified under the studied conditions. In total, one ternary and six binary compounds were confirmed, namely HoFe<sub>11</sub>Ti, TiFe<sub>2</sub>, TiFe, Fe<sub>17</sub>Ho<sub>2</sub>, Fe<sub>23</sub>Ho<sub>6</sub>, Fe<sub>3</sub>Ho, Fe<sub>2</sub>Ho. The maximum solid solubility of Ti in Fe<sub>17</sub>Ho<sub>2</sub>, Fe<sub>23</sub>Ho<sub>6</sub>, Fe<sub>3</sub>Ho, and Fe<sub>2</sub>Ho was determined to be 4.2, 1.3, 5.4, and 7.3 at.%, respectively, while the maximum solid solubility of Ho in TiFe<sub>2</sub> was 0.9 at.%. Structural characterization of the HoFe<sub>9</sub>Ti<sub>2</sub> compound showed that this phase crystallizes in the tetragonal <em>P4/mbm</em> space group. The HoFe<sub>9</sub>Ti<sub>2</sub> phase exhibits lattice parameters of a = b = 0.82113(7) nm and c = 0.48057(6) nm. Structural characterization of the HoFe<sub>11</sub>Ti compound showed that this phase crystallizes in the tetragonal <em>I4/mmm</em> space group. The HoFe<sub>11</sub>Ti phase exhibits lattice parameters of a = b = 0.84911(7) nm and c = 0.47830(1) nm.</div></div>","PeriodicalId":9436,"journal":{"name":"Calphad-computer Coupling of Phase Diagrams and Thermochemistry","volume":"91 ","pages":"Article 102895"},"PeriodicalIF":1.9,"publicationDate":"2025-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145462608","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}
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