A simple model,namely the equivalence precipitation model of η-type precipitate,has been established based on CALPHAD for the Al-Zn-Mg-1.5Cu alloy with a rich Al angle.The relationship of the theoretical mass fractio...A simple model,namely the equivalence precipitation model of η-type precipitate,has been established based on CALPHAD for the Al-Zn-Mg-1.5Cu alloy with a rich Al angle.The relationship of the theoretical mass fraction of η-type precipitate,the total content of Zn and Mg,and the Zn/Mg ratio is disclosed through the equivalence precipitation model.Moreover,the evolution of microstructure and mechanical properties in alloys with different theoretical mass fractions of η-type precipitate are explored.The findings imply that the fluctuation of theoretical mass fraction of η-type precipitate in the alloy primarily impacts the precipitation behavior of η-type precipitate.The increase of theoretical mass fraction of η-type precipitate leads to a higher volume fraction of η'phase,resulting in an improvement in strength.However,alloys with a higher theoretical mass fraction of η-type precipitate are inclined to form the quench-inducedηphase,showing higher quench sensitivity.These results are attributed to the regulation of the precipitation behavior by the total content of Zn and Mg and the Zn/Mg ratio with different theoretical mass fractions of η-type precipitate.Experimental verification has demonstrated that the equivalence precipitation model can effectively predict precipitation strengthening and evaluate the quench sensitivity of Al-Zn-Mg-1.5Cu alloys.展开更多
High pressure solution treatment,followed by ambient pressure aging treatment,may serve as a powerful tool for enhancing the alloy properties by tailoring plenty of nanoscale precipitates.However,no theoretical descri...High pressure solution treatment,followed by ambient pressure aging treatment,may serve as a powerful tool for enhancing the alloy properties by tailoring plenty of nanoscale precipitates.However,no theoretical descriptions of the microstructure evolution and prediction of mechanical properties during high pressure heat treatment(HPHT)exist.In this work,a novel atomic mobility model for binary system under pressure was first developed in the framework of CALculation of PHAse Diagram(CALPHAD)approach and applied to assess the pressure-dependent atomic mobilities of(Al)phase in the Al-Si system.Then,quantitative simulation of particle dissolution and precipitation growth for HPHT Al-Si alloys was achieved through the CALPHAD tools by coupling the present pressure-dependent atomic mobilities together with previously established thermodynamic descriptions.Finally,the relationship among composition,process,microstructure,and properties was constructed by combining the CALPHAD and machine learning methods to predict the hardness values for HPHT Al-Si alloys over a wide range of compositions and processes with limited experimental data.This work contributes to realizing the quantitative simulation of microstructure evolution and accurate prediction of mechanical properties in HPHT alloys and illustrates pathways to accelerate the discovery of advanced alloys.展开更多
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
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financially supported by the National Key Research and Development Program of China(No.2023YFB3710501).
文摘A simple model,namely the equivalence precipitation model of η-type precipitate,has been established based on CALPHAD for the Al-Zn-Mg-1.5Cu alloy with a rich Al angle.The relationship of the theoretical mass fraction of η-type precipitate,the total content of Zn and Mg,and the Zn/Mg ratio is disclosed through the equivalence precipitation model.Moreover,the evolution of microstructure and mechanical properties in alloys with different theoretical mass fractions of η-type precipitate are explored.The findings imply that the fluctuation of theoretical mass fraction of η-type precipitate in the alloy primarily impacts the precipitation behavior of η-type precipitate.The increase of theoretical mass fraction of η-type precipitate leads to a higher volume fraction of η'phase,resulting in an improvement in strength.However,alloys with a higher theoretical mass fraction of η-type precipitate are inclined to form the quench-inducedηphase,showing higher quench sensitivity.These results are attributed to the regulation of the precipitation behavior by the total content of Zn and Mg and the Zn/Mg ratio with different theoretical mass fractions of η-type precipitate.Experimental verification has demonstrated that the equivalence precipitation model can effectively predict precipitation strengthening and evaluate the quench sensitivity of Al-Zn-Mg-1.5Cu alloys.
基金supported by the National Key Research and Development Program of China(Grant No.2019YFB2006500)the Science and Technology Program of Guangxi province,China(Grant No.AB21220028)+5 种基金the Lvyangjinfeng Talent program of Yangzhou.Qian Li acknowledges the financial support from the National Natural Science Foundation of China(Grant No.U2102212)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)financial support from the Youth Fund of the National Natural Science Foundation of China(Grant No.52401047)the China Postdoctoral Science Foundation(Grant No.2023M741244)financial support from the Postdoctoral Fellowship Program of CPSF(Grant No.GZC20233311).
文摘High pressure solution treatment,followed by ambient pressure aging treatment,may serve as a powerful tool for enhancing the alloy properties by tailoring plenty of nanoscale precipitates.However,no theoretical descriptions of the microstructure evolution and prediction of mechanical properties during high pressure heat treatment(HPHT)exist.In this work,a novel atomic mobility model for binary system under pressure was first developed in the framework of CALculation of PHAse Diagram(CALPHAD)approach and applied to assess the pressure-dependent atomic mobilities of(Al)phase in the Al-Si system.Then,quantitative simulation of particle dissolution and precipitation growth for HPHT Al-Si alloys was achieved through the CALPHAD tools by coupling the present pressure-dependent atomic mobilities together with previously established thermodynamic descriptions.Finally,the relationship among composition,process,microstructure,and properties was constructed by combining the CALPHAD and machine learning methods to predict the hardness values for HPHT Al-Si alloys over a wide range of compositions and processes with limited experimental data.This work contributes to realizing the quantitative simulation of microstructure evolution and accurate prediction of mechanical properties in HPHT alloys and illustrates pathways to accelerate the discovery of advanced alloys.
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.
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.
