Designing high-performance high-entropy alloys(HEAs)with transformation-induced plasticity(TRIP)or twinning-induced plasticity(TWIP)effects requires precise control over stacking fault energy(SFE)and phase stability.H...Designing high-performance high-entropy alloys(HEAs)with transformation-induced plasticity(TRIP)or twinning-induced plasticity(TWIP)effects requires precise control over stacking fault energy(SFE)and phase stability.However,the vast complexity of multicomponent systems poses a major challenge for identifying promising candidates through conventional experimental or computational methods.A high-throughput CALPHAD framework is developed to identify compositions with potential TWIP/TRIP behaviors in the Cr-Co-Ni and Cr-Co-Ni-Fe systems through systematic screening of stacking fault energy(SFE),FCC phase stability,and FCC-to-HCP transition temperatures(T0).The approach combines TC-Python automation with parallel Gibbs energy calculations across hundreds of thousands of compositions,enabling efficient extraction of metastable FCC-dominant alloys.The high-throughput results find 214 compositions with desired properties from 160,000 candidates.Detailed analysis of the Gibbs energy distributions,phase fraction trends,and temperature-dependent SFE evolution reveals critical insights into the thermodynamic landscape governing plasticity mechanisms in HEAs.The results show that only a narrow region of the compositional space satisfies all screening criteria,emphasizing the necessity of an integrated approach.The screened compositions and trends provide a foundation for targeted experimental validation.Furthermore,this work demonstrates a scalable,composition-resolved strategy for predicting deformation mechanisms in multicomponent alloys and offers a blueprint for integrating thermodynamic screening with mechanistic understanding in HEA design.展开更多
Metal additive manufacturing(MAM)technology has experienced rapid development in recent years.As both equipment and materials progress towards increased maturity and commercialization,material metallurgy technology ba...Metal additive manufacturing(MAM)technology has experienced rapid development in recent years.As both equipment and materials progress towards increased maturity and commercialization,material metallurgy technology based on high energy sources has become a key factor influencing the future development of MAM.The calculation of phase diagrams(CALPHAD)is an essential method and tool for constructing multi-component phase diagrams by employing experimental phase diagrams and Gibbs free energy models of simple systems.By combining with the element mobility data and non-equilibrium phase transition model,it has been widely used in the analysis of traditional metal materials.The development of CALPHAD application technology for MAM is focused on the compositional design of printable materials,the reduction of metallurgical imperfections,and the control of microstructural attributes.This endeavor carries considerable theoretical and practical significance.This paper summarizes the important achievements of CALPHAD in additive manufacturing(AM)technology in recent years,including material design,process parameter optimization,microstructure evolution simulation,and properties prediction.Finally,the limitations of applying CALPHAD technology to MAM technology are discussed,along with prospective research directions.展开更多
High pressure technology has been utilized as an important means to regulate phase structure and improve the properties/performance of alloys.The CALPHAD approach based on accurate databases has great advantages in ef...High pressure technology has been utilized as an important means to regulate phase structure and improve the properties/performance of alloys.The CALPHAD approach based on accurate databases has great advantages in efficient alloy design.However,the application of CALPHAD in high pressure field is hindered by the lack of reliable thermodynamic model/database for multicomponent alloys under pressure.In this paper,a phenomenologically thermodynamic model for multicomponent alloys under pressure is first developed by separating the contribution into two parts,one is at atmosphere pressure and the other is caused by an increase in pressure,and then successfully applied to establish the pressure-dependent thermodynamic database of ternary Al-Si-Mg system.The calculated phase equilibria/thermodynamic properties of pressure dependence in related alloys are in good agreement with the limited experimental data in the literature,validating the reliability of the obtained thermodynamic database.After that,a CALPHAD design framework for pressurized solidified alloys is proposed by integrating the present pressure-dependent thermodynamic model/database,CALPHAD-type calculations/simulations,and previously developed high-throughput calculation platform Malac-Distmas.Such a framework is finally applied to predict the pressurized solidification and high pressure heat treatment behaviors in different Al-Si-Mg alloys.The predicted microstructure,phase transitions and phase equilibria after pressurized solidification and high pressure heat treatment are consistent with the experimental data.Furthermore,the insights into effect of pressure on the thermodynamic essence of alloys are gained,which may definitely facilitate the advancement of alloy design under high pressure technology.展开更多
基于纯金属杨氏模量的实验信息,本研究对纯金属的杨氏模量随温度变化的半经验模型中的参数进行了优化.借鉴相图计算的CALPHAD(calculation of phase diagram)方法,构建了多元合金杨氏模量计算的模型.基于二元合金的杨氏模量实验信息,对F...基于纯金属杨氏模量的实验信息,本研究对纯金属的杨氏模量随温度变化的半经验模型中的参数进行了优化.借鉴相图计算的CALPHAD(calculation of phase diagram)方法,构建了多元合金杨氏模量计算的模型.基于二元合金的杨氏模量实验信息,对Fe-Ni和Ta-Mo二元系的杨氏模量计算参数进行了优化,计算了合金在不同温度和成分时的杨氏模量,计算结果与实验数据取得了良好的一致性.基于二元合金的优化参数,运用三元合金的计算模型,预测了TaNb-W和Ta-Nb-Mo在不同温度和成分时的杨氏模量.展开更多
It is widely reported that CALPHAD is an extrapolation method when the thermodynamic properties of a multicomponent system are approximated by its subsystems.In this work the meaning of the words extrapolation and int...It is widely reported that CALPHAD is an extrapolation method when the thermodynamic properties of a multicomponent system are approximated by its subsystems.In this work the meaning of the words extrapolation and interpolation is discussed in context of the CALPHAD method.When assessing the properties in binary and ternary systems,extrapolation method is indeed often used.However,after assessment,the Gibbs energies are in fact interpolated from the lower order systems into the higher order systems in the compositional space.The metastable melting temperatures of bcc and hep in Re-W and the liquid miscibility gap in Mg-Zr system are predicted to illustrate the difference between interpolation and extrapolation.展开更多
A high Si reduced activation ferritic/martensitic(RAFM) steel for nuclear structure application is successfully designed by using Calphad method. The main designed chemical composition is C 0.18–0.22%, Cr10.0–10.5%,...A high Si reduced activation ferritic/martensitic(RAFM) steel for nuclear structure application is successfully designed by using Calphad method. The main designed chemical composition is C 0.18–0.22%, Cr10.0–10.5%, W 1.0–1.5%, Si 1.0–1.3%, V+Ta 0.30–0.45%, and Fe in balance. High Si design brings excellent corrosion resistance, while low activation is advantageous in the nuclear waste processing. The experimental results indicate that the newly designed high Si RAFM steel had full martensitic structure and uniformly distributed fine second phase particles, and exhibited excellent mechanical properties and corrosion resistance. Compared to the P91 steel, this new RAFM steel designed by Calphad method is expected to be a promising candidate used in nuclear power generation, which also provides a new and effective approach to the development of RAFM steel for nuclear application.展开更多
In this paper,a comprehensive understanding of stable and metastable phase equilibria in binary Mg-Gd system was conducted with an aid of the CALculation of PHAse Diagram(CALPHAD)modeling.Firstly,thermodynamic descrip...In this paper,a comprehensive understanding of stable and metastable phase equilibria in binary Mg-Gd system was conducted with an aid of the CALculation of PHAse Diagram(CALPHAD)modeling.Firstly,thermodynamic descriptions of all the stable phases in the Mg-Gd system were re-assessed by considering all the experimental data in the literature.The discrepancy between the phase equilibria and thermochemical properties existing in the previous assessments was eliminated,and the better agreement with the experimental data was achieved in the present assessment.Secondly,the Gibbs energies for metastable β"-Mg3Gd and β"-Mg7Gd were constructed based on the first-principles and CALPHAD computed results as well as their correlation,and then incorporated into the CALPHAD descriptions.The model-predicted solvuses of(Mg)in equilibrium with the metastable β"-Mg7Gd and β'-Mg7Gd compounds showed very good agreement with the limited experimental data.Finally,the presently obtained thermodynamic descriptions of both stable and metastable phases in the binary Mg-Gd system were further validated by realizing the quantitative Scheil-Gulliver solidification simulations of 5 as-cast Mg-Gd alloys,and the successful prediction of the precipitation sequences in Mg-15Gd and Mg-12Gd alloys during the aging process.展开更多
This study used the pseudo-spinodal mechanism to obtain the ultrafineαphase for designing highstrength titanium alloy.Diffusion multiple experiments were designed to find the composition range of TM-x Mo-y V alloy(TM...This study used the pseudo-spinodal mechanism to obtain the ultrafineαphase for designing highstrength titanium alloy.Diffusion multiple experiments were designed to find the composition range of TM-x Mo-y V alloy(TM:Ti-4.5 Al-2 Cr-2.5 Nb-2 Zr-1 Sn)for obtaining ultrafineαphase.CALPHAD results confirm that when the alloy composition is located near the intersection of theαandβphase free energy curves,the alloy will undergo pseudo-spinodal transformation and obtain the ultrafineαphase.The designed TM-6 Mo-3 V alloy has a yield strength of 1411 MPa and an elongation of 6.5%.The strength of the alloy depends on the thickness,fraction of theαphase and the solid solution strengthening effect of the alloying elements.The deformation mechanism of the alloy is the dislocation slip of theαandβphases and the twin deformation of theαphase.The large number ofα/βinterfaces produced by the fineαphase is the main reason for limiting the ductility of the alloy.The use of the pseudo-spinodal mechanism combined with diffusion multiple experiments and CALPHAD is an effective method for designing high-strength titanium alloys.展开更多
The Co-Cr-Ni ternary system was critically assessed using the CALPHAD technique.The solution phases including the liquid,γ(Co,Ni),εCo and αCr phases were described by a substitutional solution model.The·phase ...The Co-Cr-Ni ternary system was critically assessed using the CALPHAD technique.The solution phases including the liquid,γ(Co,Ni),εCo and αCr phases were described by a substitutional solution model.The·phase was characterized by a three-sublattice model of (Co,Ni)8Cr4(Co,Cr,Ni)18 in order to reproduce its homogeneity range determined by experiments.A self-consistent set of thermodynamic parameters for each phase was derived.展开更多
To obtain the aluminum alloy with high thermal and mechanical properties,the effects of alloying elements and the second phases on the thermal conductivity of Al alloys were investigated by CALPHAD and first-principle...To obtain the aluminum alloy with high thermal and mechanical properties,the effects of alloying elements and the second phases on the thermal conductivity of Al alloys were investigated by CALPHAD and first-principles calculation,respectively.The properties of the second phases,including Young's modulus,Poisson's ratio and minimum thermal conductivity,were systematically studied.Results show that the ranking order of the effects of the alloying elements on the thermal conductivity is Mg>Cu>Fe>Si,and for Al-12Si alloys,the mathematical model of the relationship between the alloying elements and the thermal conductivity can be expressed as λ=ax^(2)-bx+c when the second phase precipitates in the matrix.All kinds of ternary phases of Al-Fe-Si have higher deformation resistance,rigidity,theoretical hardness,Debye temperature and thermal conductivity than the other phases which possibly exist in the Al-12Si alloys.Based on the guidance of CALPHAD and first-principles calculation,the optimized chemical composition of Al alloy with high conductivity is Al-11.5Si-0.4Fe-0.2Mg(wt.%)with a thermal conductivity of 137.50 W·m^(-1)·K^(-1)and a hardness of 81.3 HBW.展开更多
基金supported by the U.S.Army Research Laboratory through their award#W911NF-22-2-0040the Ministry of Education,Youth and Sports of the Czech Republic through the e-INFRA CZ(ID:90254).
文摘Designing high-performance high-entropy alloys(HEAs)with transformation-induced plasticity(TRIP)or twinning-induced plasticity(TWIP)effects requires precise control over stacking fault energy(SFE)and phase stability.However,the vast complexity of multicomponent systems poses a major challenge for identifying promising candidates through conventional experimental or computational methods.A high-throughput CALPHAD framework is developed to identify compositions with potential TWIP/TRIP behaviors in the Cr-Co-Ni and Cr-Co-Ni-Fe systems through systematic screening of stacking fault energy(SFE),FCC phase stability,and FCC-to-HCP transition temperatures(T0).The approach combines TC-Python automation with parallel Gibbs energy calculations across hundreds of thousands of compositions,enabling efficient extraction of metastable FCC-dominant alloys.The high-throughput results find 214 compositions with desired properties from 160,000 candidates.Detailed analysis of the Gibbs energy distributions,phase fraction trends,and temperature-dependent SFE evolution reveals critical insights into the thermodynamic landscape governing plasticity mechanisms in HEAs.The results show that only a narrow region of the compositional space satisfies all screening criteria,emphasizing the necessity of an integrated approach.The screened compositions and trends provide a foundation for targeted experimental validation.Furthermore,this work demonstrates a scalable,composition-resolved strategy for predicting deformation mechanisms in multicomponent alloys and offers a blueprint for integrating thermodynamic screening with mechanistic understanding in HEA design.
基金supported by the National Key Research and Development Program of China(No.2021YFB3702500)。
文摘Metal additive manufacturing(MAM)technology has experienced rapid development in recent years.As both equipment and materials progress towards increased maturity and commercialization,material metallurgy technology based on high energy sources has become a key factor influencing the future development of MAM.The calculation of phase diagrams(CALPHAD)is an essential method and tool for constructing multi-component phase diagrams by employing experimental phase diagrams and Gibbs free energy models of simple systems.By combining with the element mobility data and non-equilibrium phase transition model,it has been widely used in the analysis of traditional metal materials.The development of CALPHAD application technology for MAM is focused on the compositional design of printable materials,the reduction of metallurgical imperfections,and the control of microstructural attributes.This endeavor carries considerable theoretical and practical significance.This paper summarizes the important achievements of CALPHAD in additive manufacturing(AM)technology in recent years,including material design,process parameter optimization,microstructure evolution simulation,and properties prediction.Finally,the limitations of applying CALPHAD technology to MAM technology are discussed,along with prospective research directions.
基金supported by the Science and Technology Program of Guangxi province,China(Grant No.AB21220028)the Natural Science Foundation of Hunan Province for Distinguished Young Scholars(Grant No.2021JJ10062)+2 种基金the Lvyangjinfeng Talent program of Yangzhou.Yi Wang acknowledges the financial support from the Fundamental Research Funds for the Central Universities of Central South University(Grant No.2021zzts0094)the Hunan Provincial Innovation Foundation for Postgraduate(Grant No.CX20210094)Jianbao Gao acknowledges the financial support from China Postdoctoral Science Foundation(Grant No.2023M741244).
文摘High pressure technology has been utilized as an important means to regulate phase structure and improve the properties/performance of alloys.The CALPHAD approach based on accurate databases has great advantages in efficient alloy design.However,the application of CALPHAD in high pressure field is hindered by the lack of reliable thermodynamic model/database for multicomponent alloys under pressure.In this paper,a phenomenologically thermodynamic model for multicomponent alloys under pressure is first developed by separating the contribution into two parts,one is at atmosphere pressure and the other is caused by an increase in pressure,and then successfully applied to establish the pressure-dependent thermodynamic database of ternary Al-Si-Mg system.The calculated phase equilibria/thermodynamic properties of pressure dependence in related alloys are in good agreement with the limited experimental data in the literature,validating the reliability of the obtained thermodynamic database.After that,a CALPHAD design framework for pressurized solidified alloys is proposed by integrating the present pressure-dependent thermodynamic model/database,CALPHAD-type calculations/simulations,and previously developed high-throughput calculation platform Malac-Distmas.Such a framework is finally applied to predict the pressurized solidification and high pressure heat treatment behaviors in different Al-Si-Mg alloys.The predicted microstructure,phase transitions and phase equilibria after pressurized solidification and high pressure heat treatment are consistent with the experimental data.Furthermore,the insights into effect of pressure on the thermodynamic essence of alloys are gained,which may definitely facilitate the advancement of alloy design under high pressure technology.
文摘基于纯金属杨氏模量的实验信息,本研究对纯金属的杨氏模量随温度变化的半经验模型中的参数进行了优化.借鉴相图计算的CALPHAD(calculation of phase diagram)方法,构建了多元合金杨氏模量计算的模型.基于二元合金的杨氏模量实验信息,对Fe-Ni和Ta-Mo二元系的杨氏模量计算参数进行了优化,计算了合金在不同温度和成分时的杨氏模量,计算结果与实验数据取得了良好的一致性.基于二元合金的优化参数,运用三元合金的计算模型,预测了TaNb-W和Ta-Nb-Mo在不同温度和成分时的杨氏模量.
基金financial support from the National Natural Science Foundation of China (Nos. 51671118 and 51871143)Young Elite Scientists Sponsorship Program by CAST (No. 2017QNRC001)+2 种基金the “Chenguang” project supported by Shanghai Municipal Education Commission and Shanghai Education Development Foundation (No. 17CG42)Science and Technology Committee of Shanghai (No. 16520721800)Aeronautical Science Fund ¨Integrated computational research of the additive manufacturing for ultra-high strength Ti alloys¨(No. 2017ZF25022)
文摘It is widely reported that CALPHAD is an extrapolation method when the thermodynamic properties of a multicomponent system are approximated by its subsystems.In this work the meaning of the words extrapolation and interpolation is discussed in context of the CALPHAD method.When assessing the properties in binary and ternary systems,extrapolation method is indeed often used.However,after assessment,the Gibbs energies are in fact interpolated from the lower order systems into the higher order systems in the compositional space.The metastable melting temperatures of bcc and hep in Re-W and the liquid miscibility gap in Mg-Zr system are predicted to illustrate the difference between interpolation and extrapolation.
基金supported by "Excellent Scholar Funding" with the title of "R&D on advanced structural steels in new nuclear energy system" initialed by Institute for Materials Research, Chinese Academy (grant number: Y7A7A111A1)
文摘A high Si reduced activation ferritic/martensitic(RAFM) steel for nuclear structure application is successfully designed by using Calphad method. The main designed chemical composition is C 0.18–0.22%, Cr10.0–10.5%, W 1.0–1.5%, Si 1.0–1.3%, V+Ta 0.30–0.45%, and Fe in balance. High Si design brings excellent corrosion resistance, while low activation is advantageous in the nuclear waste processing. The experimental results indicate that the newly designed high Si RAFM steel had full martensitic structure and uniformly distributed fine second phase particles, and exhibited excellent mechanical properties and corrosion resistance. Compared to the P91 steel, this new RAFM steel designed by Calphad method is expected to be a promising candidate used in nuclear power generation, which also provides a new and effective approach to the development of RAFM steel for nuclear application.
基金The financial support from the National Key Research and Development Program of China(Grant no.2016YFB0301101)the Hunan Provincial Science and Technology Program of China(Grant no.2017RS3002)-Huxiang Youth Talent Plan+2 种基金the Youth Talent Project of Innovation-driven Plan at Central South University(Grant no.2019XZ027)the Hebei Provincial Science and Technology Program of China(Grant no.BJ2018026)-Outstanding Young Talents Plan is acknowledgedYing Tang acknowledges the financial support from the Yuanguang fellowship released by Hebei University of Technology.
文摘In this paper,a comprehensive understanding of stable and metastable phase equilibria in binary Mg-Gd system was conducted with an aid of the CALculation of PHAse Diagram(CALPHAD)modeling.Firstly,thermodynamic descriptions of all the stable phases in the Mg-Gd system were re-assessed by considering all the experimental data in the literature.The discrepancy between the phase equilibria and thermochemical properties existing in the previous assessments was eliminated,and the better agreement with the experimental data was achieved in the present assessment.Secondly,the Gibbs energies for metastable β"-Mg3Gd and β"-Mg7Gd were constructed based on the first-principles and CALPHAD computed results as well as their correlation,and then incorporated into the CALPHAD descriptions.The model-predicted solvuses of(Mg)in equilibrium with the metastable β"-Mg7Gd and β'-Mg7Gd compounds showed very good agreement with the limited experimental data.Finally,the presently obtained thermodynamic descriptions of both stable and metastable phases in the binary Mg-Gd system were further validated by realizing the quantitative Scheil-Gulliver solidification simulations of 5 as-cast Mg-Gd alloys,and the successful prediction of the precipitation sequences in Mg-15Gd and Mg-12Gd alloys during the aging process.
基金the National Key Technologies R&D Program of China(Nos.2018YFB0704100 and 2016YFB0701301)the National Natural Science Foundation of China(Nos.51901251 and 51671218)the Natural Science Foundation of Hunan Province China(No.2020JJ5750)。
文摘This study used the pseudo-spinodal mechanism to obtain the ultrafineαphase for designing highstrength titanium alloy.Diffusion multiple experiments were designed to find the composition range of TM-x Mo-y V alloy(TM:Ti-4.5 Al-2 Cr-2.5 Nb-2 Zr-1 Sn)for obtaining ultrafineαphase.CALPHAD results confirm that when the alloy composition is located near the intersection of theαandβphase free energy curves,the alloy will undergo pseudo-spinodal transformation and obtain the ultrafineαphase.The designed TM-6 Mo-3 V alloy has a yield strength of 1411 MPa and an elongation of 6.5%.The strength of the alloy depends on the thickness,fraction of theαphase and the solid solution strengthening effect of the alloying elements.The deformation mechanism of the alloy is the dislocation slip of theαandβphases and the twin deformation of theαphase.The large number ofα/βinterfaces produced by the fineαphase is the main reason for limiting the ductility of the alloy.The use of the pseudo-spinodal mechanism combined with diffusion multiple experiments and CALPHAD is an effective method for designing high-strength titanium alloys.
基金financially supported by the National Natural Science Foundation of China (No.50771027)
文摘The Co-Cr-Ni ternary system was critically assessed using the CALPHAD technique.The solution phases including the liquid,γ(Co,Ni),εCo and αCr phases were described by a substitutional solution model.The·phase was characterized by a three-sublattice model of (Co,Ni)8Cr4(Co,Cr,Ni)18 in order to reproduce its homogeneity range determined by experiments.A self-consistent set of thermodynamic parameters for each phase was derived.
基金the National Natural Science Foundation of China(Nos.51801045 and 52171113)the Key Laboratory of Materials Modification by Laser,Ion and Electron Beams,Ministry of Education,Dalian University of Technology(No.KF2002).
文摘To obtain the aluminum alloy with high thermal and mechanical properties,the effects of alloying elements and the second phases on the thermal conductivity of Al alloys were investigated by CALPHAD and first-principles calculation,respectively.The properties of the second phases,including Young's modulus,Poisson's ratio and minimum thermal conductivity,were systematically studied.Results show that the ranking order of the effects of the alloying elements on the thermal conductivity is Mg>Cu>Fe>Si,and for Al-12Si alloys,the mathematical model of the relationship between the alloying elements and the thermal conductivity can be expressed as λ=ax^(2)-bx+c when the second phase precipitates in the matrix.All kinds of ternary phases of Al-Fe-Si have higher deformation resistance,rigidity,theoretical hardness,Debye temperature and thermal conductivity than the other phases which possibly exist in the Al-12Si alloys.Based on the guidance of CALPHAD and first-principles calculation,the optimized chemical composition of Al alloy with high conductivity is Al-11.5Si-0.4Fe-0.2Mg(wt.%)with a thermal conductivity of 137.50 W·m^(-1)·K^(-1)and a hardness of 81.3 HBW.
