Pub Date : 2025-02-24DOI: 10.1016/j.calphad.2025.102804
Hong Bo, Rui Cheng, Yanwei Han, Xudong Chen, Li-min Wang
As a ternary subsystem of the high-temperature bulk metallic glass system, the Co-Ni-B system was systematically studied through both experimentation and thermodynamic modeling. Using equilibrated alloys, the isothermal section at 1073 K was investigated via electron probe microanalyzer (EPMA) equipped with wavelength dispersive spectrometer (WDS) and x-ray diffraction (XRD). Differential scanning calorimetry (DSC) tests were also conducted to determine the phase transition temperatures. By combining the experimental data and first-principles calculation results from this work, the Co-Ni-B system was thermodynamically optimized with the CALculation of PHAse Diagram (CALPHAD) method. The calculated isothermal section, vertical section and liquidus projection accounted for the experimental data successfully. This study provides a foundation for establishing a multi-component thermodynamic database that includes Co-Ni-B and facilitates the design of novel high-temperature metallic glasses.
{"title":"Experimental investigation and thermodynamic modeling of the Co-Ni-B system","authors":"Hong Bo, Rui Cheng, Yanwei Han, Xudong Chen, Li-min Wang","doi":"10.1016/j.calphad.2025.102804","DOIUrl":"10.1016/j.calphad.2025.102804","url":null,"abstract":"<div><div>As a ternary subsystem of the high-temperature bulk metallic glass system, the Co-Ni-B system was systematically studied through both experimentation and thermodynamic modeling. Using equilibrated alloys, the isothermal section at 1073 K was investigated via electron probe microanalyzer (EPMA) equipped with wavelength dispersive spectrometer (WDS) and x-ray diffraction (XRD). Differential scanning calorimetry (DSC) tests were also conducted to determine the phase transition temperatures. By combining the experimental data and first-principles calculation results from this work, the Co-Ni-B system was thermodynamically optimized with the CALculation of PHAse Diagram (CALPHAD) method. The calculated isothermal section, vertical section and liquidus projection accounted for the experimental data successfully. This study provides a foundation for establishing a multi-component thermodynamic database that includes Co-Ni-B and facilitates the design of novel high-temperature metallic glasses.</div></div>","PeriodicalId":9436,"journal":{"name":"Calphad-computer Coupling of Phase Diagrams and Thermochemistry","volume":"88 ","pages":"Article 102804"},"PeriodicalIF":1.9,"publicationDate":"2025-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143474458","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 : 2025-02-18DOI: 10.1016/j.calphad.2025.102808
Mingzhong Yuan, Changrong Li, Cuiping Guo, Zhenmin Du
The phase relationships of the Sc-Sb binary system were experimentally investigated using the heat-treated alloys as well as the as-cast alloys by scanning electron microscopy with energy dispersive spectrometer (SEM-EDS), powder X-ray diffraction (XRD) and differential scanning calorimetry (DSC). Four stable intermetallic phases, Sc2Sb, Sc4Sb2.52, Sc5Sb3 and ScSb, are confirmed to exist in the Sc-Sb binary system. The phases Sc5Sb3, Sc4Sb2.52 and ScSb solidify congruently while the phases Sc2Sb is formed through the peritectic transformation. There are six invariant reactions in the Sc-Sb system. The liquid compositions of the four eutectic isothermal reactions are approximately 16.3 at.% Sb at 1188 °C for L → α-Sc + Sc2Sb, 38.3 at.% Sb at 1548 °C for L → Sc5Sb3 + Sc4Sb2.52, 48.4 at.% Sb at 1442 °C for L → Sc4Sb2.52 + ScSb and 88.0 at.% Sb at 575 °C for L → ScSb + Rhom-Sb, and a peritectic isothermal reaction is about 23.2 at.% Sb at 1349 °C for L + Sc5Sb3 → Sc2Sb. The liquid composition of the metatectic isothermal reaction β-Sc → α-Sc + L is 14.39 at.% Sb at 1263 °C. The solubilities of Sb in α-Sc are 3.8, 4.8 and 5.5 at.% Sb at 1000, 1100 and 1200 °C, respectively. According to the experimental heat capacity of the Sc4Sb2.52 compound, the Gibbs energy of this compound was firstly determined from 0 to 2000 K. Based on the presently obtained experimental data and the data from literatures, the Sc-Sb system was thermodynamically described and critically assessed by means of the CALPHAD approach. A self-consistent set of thermodynamic parameters was obtained. The calculated results show good agreement with the experimental data.
{"title":"Experimental investigation and thermodynamic optimization of the Sc-Sb binary system","authors":"Mingzhong Yuan, Changrong Li, Cuiping Guo, Zhenmin Du","doi":"10.1016/j.calphad.2025.102808","DOIUrl":"10.1016/j.calphad.2025.102808","url":null,"abstract":"<div><div>The phase relationships of the Sc-Sb binary system were experimentally investigated using the heat-treated alloys as well as the as-cast alloys by scanning electron microscopy with energy dispersive spectrometer (SEM-EDS), powder X-ray diffraction (XRD) and differential scanning calorimetry (DSC). Four stable intermetallic phases, Sc<sub>2</sub>Sb, Sc<sub>4</sub>Sb<sub>2.52</sub>, Sc<sub>5</sub>Sb<sub>3</sub> and ScSb, are confirmed to exist in the Sc-Sb binary system. The phases Sc<sub>5</sub>Sb<sub>3</sub>, Sc<sub>4</sub>Sb<sub>2.52</sub> and ScSb solidify congruently while the phases Sc<sub>2</sub>Sb is formed through the peritectic transformation. There are six invariant reactions in the Sc-Sb system. The liquid compositions of the four eutectic isothermal reactions are approximately 16.3 at.% Sb at 1188 °C for L → <em>α</em>-Sc + Sc<sub>2</sub>Sb, 38.3 at.% Sb at 1548 °C for L → Sc<sub>5</sub>Sb<sub>3</sub> + Sc<sub>4</sub>Sb<sub>2.52</sub>, 48.4 at.% Sb at 1442 °C for L → Sc<sub>4</sub>Sb<sub>2.52</sub> + ScSb and 88.0 at.% Sb at 575 °C for L → ScSb + Rhom-Sb, and a peritectic isothermal reaction is about 23.2 at.% Sb at 1349 °C for L + Sc<sub>5</sub>Sb<sub>3</sub> → Sc<sub>2</sub>Sb. The liquid composition of the metatectic isothermal reaction <em>β</em>-Sc → <em>α</em>-Sc + L is 14.39 at.% Sb at 1263 °C. The solubilities of Sb in <em>α</em>-Sc are 3.8, 4.8 and 5.5 at.% Sb at 1000, 1100 and 1200 °C, respectively. According to the experimental heat capacity of the Sc<sub>4</sub>Sb<sub>2.52</sub> compound, the Gibbs energy of this compound was firstly determined from 0 to 2000 K. Based on the presently obtained experimental data and the data from literatures, the Sc-Sb system was thermodynamically described and critically assessed by means of the CALPHAD approach. A self-consistent set of thermodynamic parameters was obtained. The calculated results show good agreement with the experimental data.</div></div>","PeriodicalId":9436,"journal":{"name":"Calphad-computer Coupling of Phase Diagrams and Thermochemistry","volume":"88 ","pages":"Article 102808"},"PeriodicalIF":1.9,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143429474","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 : 2025-02-09DOI: 10.1016/j.calphad.2025.102806
Junjun Wang , Bingquan Xu , Kyungjun Lee , Wei Huang , Huihui Wang , Jian Peng , Man Xu
A machine learning assisted CALPHAD framework is applied in this study to thermodynamically analyze the chemical vapor deposition (CVD) process for silicon oxynitride films. Among the various machine learning algorithms evaluated, Random Forest (RF) was identified as the optimal model due to its superior accuracy and generalization performance. The study identified that only 5 % data of the original dataset is required to effectively train the RF model. The best-trained RF model can excellently reproduce results from CALPHAD. SHAP analysis was performed to quantify the contribution of input features to the performance of machine learning model. The results revealed that NH3/N2O and NH3/SiCl4 ratios have the most significant influence on the mole fractions of SiO2 and Si2N2O, while the NH3/N2O ratio is the dominant factor affecting the mole fraction of Si3N4 in the deposit. Notably, the ML-assisted CALPHAD framework demonstrated a 20-fold increase in analysis efficiency compared to traditional CALPHAD calculations.
{"title":"Machine learning assisted CALPHAD framework for thermodynamic analysis of CVD SiOxNy thin films","authors":"Junjun Wang , Bingquan Xu , Kyungjun Lee , Wei Huang , Huihui Wang , Jian Peng , Man Xu","doi":"10.1016/j.calphad.2025.102806","DOIUrl":"10.1016/j.calphad.2025.102806","url":null,"abstract":"<div><div>A machine learning assisted CALPHAD framework is applied in this study to thermodynamically analyze the chemical vapor deposition (CVD) process for silicon oxynitride films. Among the various machine learning algorithms evaluated, Random Forest (RF) was identified as the optimal model due to its superior accuracy and generalization performance. The study identified that only 5 % data of the original dataset is required to effectively train the RF model. The best-trained RF model can excellently reproduce results from CALPHAD. SHAP analysis was performed to quantify the contribution of input features to the performance of machine learning model. The results revealed that NH<sub>3</sub>/N<sub>2</sub>O and NH<sub>3</sub>/SiCl<sub>4</sub> ratios have the most significant influence on the mole fractions of SiO<sub>2</sub> and Si<sub>2</sub>N<sub>2</sub>O, while the NH<sub>3</sub>/N<sub>2</sub>O ratio is the dominant factor affecting the mole fraction of Si<sub>3</sub>N<sub>4</sub> in the deposit. Notably, the ML-assisted CALPHAD framework demonstrated a 20-fold increase in analysis efficiency compared to traditional CALPHAD calculations.</div></div>","PeriodicalId":9436,"journal":{"name":"Calphad-computer Coupling of Phase Diagrams and Thermochemistry","volume":"88 ","pages":"Article 102806"},"PeriodicalIF":1.9,"publicationDate":"2025-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143372392","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 : 2025-02-08DOI: 10.1016/j.calphad.2025.102798
Xiaoke Wu , Ting Cheng , Jing Zhong , Shenglan Yang , Sa Ma , Na Ta , Lijun Zhang
In this work, a framework for efficient phase-field simulation of microstructure evolution is developed and demonstrated in Ni-based superalloys. Firstly, a universal schema for phase-field simulation coupling with various CALPHAD-type data/databases is postulated. Identifiers for illustrating fruitful prerequisite properties/parameters for phase-field modeling are proposed. An open exchange coupling file format is also put forward according to the data reconstruction strategy based on hash algorithm and interpolation. After that, the presently developed coupling schema is combined with the phase-field model with finite interface dissipation as well as the parallelism technique for elaborate demonstration. Various benchmark tests for the presently proposed coupling schema are carried out for validation. Finally, efficient phase-field simulation of the long-time aging process of Ni-Al alloy and the medium-scale directional solidification process of the Ni-Al-Ta ternary alloy within various preparation process parameters were performed for further validation. It is anticipated that the presently developed framework is of general validity for industrial materials in the spirit of integrated computational materials engineering.
{"title":"An efficient microstructure simulation framework by integrating phase-field model, general coupling schema and parallelism: Demo in Ni-based superalloys","authors":"Xiaoke Wu , Ting Cheng , Jing Zhong , Shenglan Yang , Sa Ma , Na Ta , Lijun Zhang","doi":"10.1016/j.calphad.2025.102798","DOIUrl":"10.1016/j.calphad.2025.102798","url":null,"abstract":"<div><div>In this work, a framework for efficient phase-field simulation of microstructure evolution is developed and demonstrated in Ni-based superalloys. Firstly, a universal schema for phase-field simulation coupling with various CALPHAD-type data/databases is postulated. Identifiers for illustrating fruitful prerequisite properties/parameters for phase-field modeling are proposed. An open exchange coupling file format is also put forward according to the data reconstruction strategy based on hash algorithm and interpolation. After that, the presently developed coupling schema is combined with the phase-field model with finite interface dissipation as well as the parallelism technique for elaborate demonstration. Various benchmark tests for the presently proposed coupling schema are carried out for validation. Finally, efficient phase-field simulation of the long-time aging process of Ni-Al alloy and the medium-scale directional solidification process of the Ni-Al-Ta ternary alloy within various preparation process parameters were performed for further validation. It is anticipated that the presently developed framework is of general validity for industrial materials in the spirit of integrated computational materials engineering.</div></div>","PeriodicalId":9436,"journal":{"name":"Calphad-computer Coupling of Phase Diagrams and Thermochemistry","volume":"88 ","pages":"Article 102798"},"PeriodicalIF":1.9,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143351008","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 : 2025-01-31DOI: 10.1016/j.calphad.2025.102805
H. Bouchta , A. Bendarma , D.O. Poletaev , M.A. Boukideur , S. Kardellass , N. Selhaoui , L. Rabhi , M. Idbenali
In this work, a standard enthalpies of formation for metal compounds within the Eu-Rh system were determined using first-principles calculations within the framework of density functional theory (DFT). The system analysis was carried out by employing thermodynamic data and phase diagram information sourced from literature, and a CALPHAD-type optimization and Thermo-Calc software.
The Eu-Rh phase diagram includes four intermetallic compounds: All phases present a stoichiometry, except the which has a homogeneity range and was modeled using a two-sublattice model with substitution in each sublattice.
To describe the additional term of the Gibbs energy ( for the liquid phase and the solid solution within the Eu-Rh system, a solution model has been used. The liquid phase was characterized using the linear dependence of the Redlich-Kister model. The individual Gibbs energies include temperature-dependent contributions for all compounds. A comparative analysis shows a good agreement between the enthalpies of formation calculated in this study using the VASP method and current literature data. Finally, a set of self-consistent thermodynamic parameters for the Eu-Rh system was derived.
{"title":"Thermodynamic assessment of the Eu-Rh system by the combination of ab-initio calculations and CALPHAD approach","authors":"H. Bouchta , A. Bendarma , D.O. Poletaev , M.A. Boukideur , S. Kardellass , N. Selhaoui , L. Rabhi , M. Idbenali","doi":"10.1016/j.calphad.2025.102805","DOIUrl":"10.1016/j.calphad.2025.102805","url":null,"abstract":"<div><div>In this work, a standard enthalpies of formation for metal compounds within the Eu-Rh system were determined using first-principles calculations within the framework of density functional theory (DFT). The system analysis was carried out by employing thermodynamic data and phase diagram information sourced from literature, and a CALPHAD-type optimization and Thermo-Calc software.</div><div>The Eu-Rh phase diagram includes four intermetallic compounds: <span><math><mrow><msub><mtext>Eu</mtext><mn>9</mn></msub><mtext>Rh</mtext><mo>,</mo><msub><mtext>Eu</mtext><mn>3</mn></msub><mtext>Rh</mtext><mo>,</mo><msub><mtext>Eu</mtext><mn>5</mn></msub><mtext>Rh</mtext><mspace></mspace><mtext>and</mtext><mspace></mspace><mtext>Eu</mtext><msub><mtext>Rh</mtext><mrow><mn>2</mn><mspace></mspace><mo>.</mo><mspace></mspace></mrow></msub></mrow></math></span> All phases present a stoichiometry, except the <span><math><mrow><mtext>Eu</mtext><msub><mtext>Rh</mtext><mrow><mn>2</mn><mspace></mspace></mrow></msub><mtext>,</mtext></mrow></math></span> which has a homogeneity range and was modeled using a two-sublattice model with substitution in each sublattice.</div><div>To describe the additional term of the Gibbs energy (<span><math><mrow><mmultiscripts><mi>G</mi><mprescripts></mprescripts><none></none><mtext>ex</mtext></mmultiscripts><mo>)</mo></mrow></math></span> for the liquid phase and the solid solution within the Eu-Rh system, a solution model has been used. The liquid phase was characterized using the linear dependence of the Redlich-Kister model. The individual Gibbs energies include temperature-dependent contributions for all compounds. A comparative analysis shows a good agreement between the enthalpies of formation calculated in this study using the VASP method and current literature data. Finally, a set of self-consistent thermodynamic parameters for the Eu-Rh system was derived.</div></div>","PeriodicalId":9436,"journal":{"name":"Calphad-computer Coupling of Phase Diagrams and Thermochemistry","volume":"88 ","pages":"Article 102805"},"PeriodicalIF":1.9,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143180685","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 : 2025-01-30DOI: 10.1016/j.calphad.2025.102802
Ryota Nagashima, Masao Takeyama
Experimental studies were conducted to investigate the phase equilibria of the Ni-rich portion of the Ni–Cr–Mo ternary system using scanning electron microscopy and electron probe microanalysis of heat-treated alloys. Experimental isothermal sections involving L-liquid, γ-Ni, P-NiCrMo, NiMo, Ni3Mo, and Ni2(Cr, Mo)-oP6 phases were constructed at temperatures below 1573 K. Two distinct liquid phase regions with varying compositions were observed at 1573 K, indicating a phase separation of the liquid phase (L → L1 + L2). This can result in the presence of two ternary eutectic reactions: L1 → γ + P + NiMo and L2 → γ + σ + P. The Ni2Cr phase in the binary system was stabilized by substituted Cr by Mo at temperatures above 200 K. The Ni2(Cr, Mo)-oP6 single-phase region existed as an island around the composition of Ni–9Cr–24Mo (at.%) at 1073 K. The experimentally identified γ + oP6 + Ni3Mo and γ + P + oP6 regions suggest that the oP6 phase is formed by a ternary peritectoid reaction (γ + P + Ni3Mo → oP6). Based on these results, the reaction pathways related to the liquid and oP6 phases in the Ni–Cr–Mo ternary system were modified.
{"title":"Experimental phase diagram study of the Ni-rich part of the Ni–Cr–Mo ternary system","authors":"Ryota Nagashima, Masao Takeyama","doi":"10.1016/j.calphad.2025.102802","DOIUrl":"10.1016/j.calphad.2025.102802","url":null,"abstract":"<div><div>Experimental studies were conducted to investigate the phase equilibria of the Ni-rich portion of the Ni–Cr–Mo ternary system using scanning electron microscopy and electron probe microanalysis of heat-treated alloys. Experimental isothermal sections involving L-liquid, γ-Ni, P-NiCrMo, NiMo, Ni<sub>3</sub>Mo, and Ni<sub>2</sub>(Cr, Mo)-<em>oP</em>6 phases were constructed at temperatures below 1573 K. Two distinct liquid phase regions with varying compositions were observed at 1573 K, indicating a phase separation of the liquid phase (L → L<sub>1</sub> + L<sub>2</sub>). This can result in the presence of two ternary eutectic reactions: L<sub>1</sub> → γ + P + NiMo and L<sub>2</sub> → γ + σ + P. The Ni<sub>2</sub>Cr phase in the binary system was stabilized by substituted Cr by Mo at temperatures above 200 K. The Ni<sub>2</sub>(Cr, Mo)-<em>oP</em>6 single-phase region existed as an island around the composition of Ni–9Cr–24Mo (at.%) at 1073 K. The experimentally identified γ + <em>oP</em>6 + Ni<sub>3</sub>Mo and γ + P + <em>oP</em>6 regions suggest that the <em>oP</em>6 phase is formed by a ternary peritectoid reaction (γ + P + Ni<sub>3</sub>Mo → <em>oP</em>6). Based on these results, the reaction pathways related to the liquid and <em>oP</em>6 phases in the Ni–Cr–Mo ternary system were modified.</div></div>","PeriodicalId":9436,"journal":{"name":"Calphad-computer Coupling of Phase Diagrams and Thermochemistry","volume":"88 ","pages":"Article 102802"},"PeriodicalIF":1.9,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143180686","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-29DOI: 10.1016/j.calphad.2025.102803
Kai Liang, Linna Shen, Cuiping Guo, Changrong Li, Zhenmin Du
The liquidus surface projection of the Ni–Ta–Ti system was constructed in this work. Thirty-seven as-cast alloys were characterized using scanning electron microscope equipped with energy dispersive spectrometer (SEM/EDS) and X-ray diffraction (XRD) methods to analyze the primary phases and solidification paths of alloys. Ten primary solidification regions of bcc(Ta,Ti), fcc(Ni), NiTi, NiTi2, NiTa2, Ni2Ta, Ni3Ta, Ni3Ti, μ and τ were determined. The crystal structure of the intermetallic phase τ was identified as the Ni3Sn type with space group P63/mmc. Moreover, the thermodynamic parameters of the Ni–Ta–Ti system were optimized via the CALculation of PHAse Diagram (CALPHAD) method based on the available experimental data. In this work, NiTi2, Ni3Ti, NiTa2, Ni2Ta, Ni3Ta and τ were modelled by two-sublattice model (Ni,Ta,Ti)m(Ni,Ta,Ti)n. A four-sublattice model (Ni,Ta,Ti)1(Ta,Ti)4(Ni,Ta,Ti)2(Ni,Ta,Ti)6 was adopted to describe μ. The calculated liquidus surface projection and isothermal sections with the obtained thermodynamic parameters were consistent with the experimental data.
{"title":"Experimental investigation and thermodynamic optimization of the Ni–Ta–Ti system","authors":"Kai Liang, Linna Shen, Cuiping Guo, Changrong Li, Zhenmin Du","doi":"10.1016/j.calphad.2025.102803","DOIUrl":"10.1016/j.calphad.2025.102803","url":null,"abstract":"<div><div>The liquidus surface projection of the Ni–Ta–Ti system was constructed in this work. Thirty-seven as-cast alloys were characterized using scanning electron microscope equipped with energy dispersive spectrometer (SEM/EDS) and X-ray diffraction (XRD) methods to analyze the primary phases and solidification paths of alloys. Ten primary solidification regions of bcc(Ta,Ti), fcc(Ni), NiTi, NiTi<sub>2</sub>, NiTa<sub>2</sub>, Ni<sub>2</sub>Ta, Ni<sub>3</sub>Ta, Ni<sub>3</sub>Ti, μ and τ were determined. The crystal structure of the intermetallic phase τ was identified as the Ni<sub>3</sub>Sn type with space group <em>P</em>6<sub>3</sub>/<em>mmc</em>. Moreover, the thermodynamic parameters of the Ni–Ta–Ti system were optimized via the CALculation of PHAse Diagram (CALPHAD) method based on the available experimental data. In this work, NiTi<sub>2</sub>, Ni<sub>3</sub>Ti, NiTa<sub>2</sub>, Ni<sub>2</sub>Ta, Ni<sub>3</sub>Ta and τ were modelled by two-sublattice model (Ni,Ta,Ti)<sub><em>m</em></sub>(Ni,Ta,Ti)<sub><em>n</em></sub>. A four-sublattice model (Ni,Ta,Ti)<sub>1</sub>(Ta,Ti)<sub>4</sub>(Ni,Ta,Ti)<sub>2</sub>(Ni,Ta,Ti)<sub>6</sub> was adopted to describe μ. The calculated liquidus surface projection and isothermal sections with the obtained thermodynamic parameters were consistent with the experimental data.</div></div>","PeriodicalId":9436,"journal":{"name":"Calphad-computer Coupling of Phase Diagrams and Thermochemistry","volume":"88 ","pages":"Article 102803"},"PeriodicalIF":1.9,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143181092","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 : 2025-01-29DOI: 10.1016/j.calphad.2025.102800
B. Reis , F. Tang , P. Keuter, M. to Baben
The Calphad Optimizer available since FactSage 8.2 is presented. It contains both a user-friendly graphical interface, as well as input and output files that are easily readable by humans and machines. For a number of typical experiments (liquidus and solidus temperatures, two-phase equilibria, heat of mixing, heat of reaction, enthalpy increment) tailored recipes exist to enable beginners and non-specialists the input of the relevant data. For many other experimental data, user-defined experiments can also be created. Two different optimizers are currently implemented. While running the optimization, the user is presented with graphs showing the convergence progress, both globally (error sum vs. iteration), as well as for each experiment (comparison between experimental and calculated data) and for each optimization parameter (error sum vs. parameter value). As a first post-processing option, phase formation maps can be calculated.
In the latest version of the Calphad Optimizer, available since FactSage 8.3, the error sum is calculated primarily based on Gibbs energy differences, not the raw experimental data. The details of the implementation are described. Using the Pb-Sn and Cr-Ni systems as examples, we show how the change in the error sum calculation increases robustness and speed of the optimization, making one-shot Calphad database optimizations possible.
{"title":"User-friendly and robust Calphad optimizations using Calphad Optimizer in FactSage","authors":"B. Reis , F. Tang , P. Keuter, M. to Baben","doi":"10.1016/j.calphad.2025.102800","DOIUrl":"10.1016/j.calphad.2025.102800","url":null,"abstract":"<div><div>The Calphad Optimizer available since FactSage 8.2 is presented. It contains both a user-friendly graphical interface, as well as input and output files that are easily readable by humans and machines. For a number of typical experiments (liquidus and solidus temperatures, two-phase equilibria, heat of mixing, heat of reaction, enthalpy increment) tailored recipes exist to enable beginners and non-specialists the input of the relevant data. For many other experimental data, user-defined experiments can also be created. Two different optimizers are currently implemented. While running the optimization, the user is presented with graphs showing the convergence progress, both globally (error sum vs. iteration), as well as for each experiment (comparison between experimental and calculated data) and for each optimization parameter (error sum vs. parameter value). As a first post-processing option, phase formation maps can be calculated.</div><div>In the latest version of the Calphad Optimizer, available since FactSage 8.3, the error sum is calculated primarily based on Gibbs energy differences, not the raw experimental data. The details of the implementation are described. Using the Pb-Sn and Cr-Ni systems as examples, we show how the change in the error sum calculation increases robustness and speed of the optimization, making one-shot Calphad database optimizations possible.</div></div>","PeriodicalId":9436,"journal":{"name":"Calphad-computer Coupling of Phase Diagrams and Thermochemistry","volume":"88 ","pages":"Article 102800"},"PeriodicalIF":1.9,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143181095","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 : 2025-01-24DOI: 10.1016/j.calphad.2025.102801
Soumya Sridar , Liangyan Hao , Thomas Kirtley , Ethan Schneider , Toni Karlsson , Guy L. Fredrickson , Elizabeth Sooby , Wei Xiong
Sodium-cooled fast reactors utilize metallic fuels that include bond-sodium within the fuel element. Molten salt electrolysis at 773 K with eutectic KCl-LiCl mixed with UCl3 as an electrolyte can recover the actinides from spent fuel. The critical factor affecting the useful life of the electrolyte is the increase in liquidus temperature from the accumulation of lanthanides, actinides, and sodium. Therefore, thermodynamic modeling of the KCl-LiCl-NaCl-UCl3 system was carried out by considering experimental data from the present work and literature as input. The liquidus and solidus temperatures for the two ternary systems, KCl-NaCl-UCl3 and LiCl-NaCl-UCl3, were determined using differential scanning calorimetry. The thermodynamic parameters for pure UCl3 were optimized for liquid and solid states over a wide temperature range. Several constituent binary (AkCl-UCl3; Ak: K, Li, Na) and ternary (KCl-LiCl-UCl3, KCl-NaCl-UCl3 and LiCl-NaCl-UCl3) systems were assessed or reassessed in this work. A new intermediate phase (K3UCl6) was included in the reassessment for the KCl-UCl3 system. There is good agreement between the experimental and calculated thermochemical and phase diagram data for all the systems optimized in the present work. This work is beneficial to determine the effect of NaCl on the liquidus temperature and other thermodynamic properties of KCl-LiCl electrolyte mixed with UCl3 for improving the efficiency of molten salt electrolysis.
{"title":"Thermodynamic modeling of the KCl-LiCl-NaCl-UCl3 system for molten salt electrolysis and reprocessing of spent nuclear fuel","authors":"Soumya Sridar , Liangyan Hao , Thomas Kirtley , Ethan Schneider , Toni Karlsson , Guy L. Fredrickson , Elizabeth Sooby , Wei Xiong","doi":"10.1016/j.calphad.2025.102801","DOIUrl":"10.1016/j.calphad.2025.102801","url":null,"abstract":"<div><div>Sodium-cooled fast reactors utilize metallic fuels that include bond-sodium within the fuel element. Molten salt electrolysis at 773 K with eutectic KCl-LiCl mixed with UCl<sub>3</sub> as an electrolyte can recover the actinides from spent fuel. The critical factor affecting the useful life of the electrolyte is the increase in liquidus temperature from the accumulation of lanthanides, actinides, and sodium. Therefore, thermodynamic modeling of the KCl-LiCl-NaCl-UCl<sub>3</sub> system was carried out by considering experimental data from the present work and literature as input. The liquidus and solidus temperatures for the two ternary systems, KCl-NaCl-UCl<sub>3</sub> and LiCl-NaCl-UCl<sub>3,</sub> were determined using differential scanning calorimetry. The thermodynamic parameters for pure UCl<sub>3</sub> were optimized for liquid and solid states over a wide temperature range. Several constituent binary (AkCl-UCl<sub>3</sub>; Ak: K, Li, Na) and ternary (KCl-LiCl-UCl<sub>3</sub>, KCl-NaCl-UCl<sub>3</sub> and LiCl-NaCl-UCl<sub>3</sub>) systems were assessed or reassessed in this work. A new intermediate phase (K<sub>3</sub>UCl<sub>6</sub>) was included in the reassessment for the KCl-UCl<sub>3</sub> system. There is good agreement between the experimental and calculated thermochemical and phase diagram data for all the systems optimized in the present work. This work is beneficial to determine the effect of NaCl on the liquidus temperature and other thermodynamic properties of KCl-LiCl electrolyte mixed with UCl<sub>3</sub> for improving the efficiency of molten salt electrolysis.</div></div>","PeriodicalId":9436,"journal":{"name":"Calphad-computer Coupling of Phase Diagrams and Thermochemistry","volume":"88 ","pages":"Article 102801"},"PeriodicalIF":1.9,"publicationDate":"2025-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143181079","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-24DOI: 10.1016/j.calphad.2025.102799
Xi Li , Minsi Liao , Chong Chen , Cong Zhang , Shizhong Wei
The Fe-Al-Ni alloys are widely used in the thermal management systems of electronic devices and the production of electromagnetic components because of their high heat dissipation characteristics. In this work, the thermal conductivity of the Fe-Al-Ni system was evaluated by means of CALPHAD (CALculation of PHAse Diagrams) method. The thermal conductivity of solid solutions was described using Redlich-Kister interaction parameters. For alloys in a two-phase region, an interface thermal resistance parameter was introduced into the model to account for the impedance of interfaces on heat transfer. The corresponding parameters for the pure element, binary and ternary systems were optimized, which enables the modeling exhibit good consistency with the experimental data. This work is helpful for predicting the thermal conductivity of Fe-Al-Ni alloys system during the industrial production process and provide key thermophysical properties for microstructure and processing simulations.
{"title":"Thermal conductivity calculation of Fe-Al-Ni alloys by CALPHAD method","authors":"Xi Li , Minsi Liao , Chong Chen , Cong Zhang , Shizhong Wei","doi":"10.1016/j.calphad.2025.102799","DOIUrl":"10.1016/j.calphad.2025.102799","url":null,"abstract":"<div><div>The Fe-Al-Ni alloys are widely used in the thermal management systems of electronic devices and the production of electromagnetic components because of their high heat dissipation characteristics. In this work, the thermal conductivity of the Fe-Al-Ni system was evaluated by means of CALPHAD (CALculation of PHAse Diagrams) method. The thermal conductivity of solid solutions was described using Redlich-Kister interaction parameters. For alloys in a two-phase region, an interface thermal resistance parameter was introduced into the model to account for the impedance of interfaces on heat transfer. The corresponding parameters for the pure element, binary and ternary systems were optimized, which enables the modeling exhibit good consistency with the experimental data. This work is helpful for predicting the thermal conductivity of Fe-Al-Ni alloys system during the industrial production process and provide key thermophysical properties for microstructure and processing simulations.</div></div>","PeriodicalId":9436,"journal":{"name":"Calphad-computer Coupling of Phase Diagrams and Thermochemistry","volume":"88 ","pages":"Article 102799"},"PeriodicalIF":1.9,"publicationDate":"2025-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143181094","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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