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 corrosion resistance of alloys is essential for their structural applications;however,most alloys suffer from degradation of their corrosion resistance with the increasing acidity of their surround-ings.Nonethele...High corrosion resistance of alloys is essential for their structural applications;however,most alloys suffer from degradation of their corrosion resistance with the increasing acidity of their surround-ings.Nonetheless,we developed a series of medium-entropy alloys(MEAs)in this work,which ex-hibit high strength,superior fracture toughness and ultra-high corrosion resistance,outperforming the variety of corrosion resistant alloys hitherto reported.Most interestingly,our MEAs exhibit an unusual anti-corrosion behavior and their corrosion resistance increases with acidity in Cl−containing solutions.Through extensive thermodynamic calculations,density functional theory(DFT)simulations and experi-ments,we reveal that the unusual anti-corrosion behavior of our MEAs can be attributed to their surface chemical complexity,which facilitates the physio-chemical-absorption of H_(2)O and O_(2)and thus the rapid formation of metastable medium entropy passive films that contain the lowest amount of defects,as compared to the passive films on conventional alloys reported in the literature.展开更多
In order to efficiently explore the nearly infinite composition space in multicomponent solid solution alloys for reaching higher mechanical performance,it is important to establish predictive design strategies using ...In order to efficiently explore the nearly infinite composition space in multicomponent solid solution alloys for reaching higher mechanical performance,it is important to establish predictive design strategies using computation-aided methods.Here,using ab initio calculations we systematically study the effects of magnetism and chemical composition on the generalized stacking fault energy surface(γ-surface) of Cr-Co-Ni medium entropy alloys and show that both chemistry and the coupled magnetic state strongly affect the γ-surface,consequently,the primary deformation modes.The relations among various stable and unstable stacking fault energies are revealed and discussed.The present findings are useful for studying the deformation behaviors of Cr-Co-Ni alloys and facilitate a density functional theory based design of transformation-induced plasticity and twinning-induced plasticity mechanisms in Cr-Co-Ni alloys.展开更多
As potential cast and wrought Mg alloys,Mg-X(X=Al,Zn,Sn)based alloys have attracted great interest.This work is to develop a dataset of atomic mobilities that is valid over a wide composition range.With the obtained m...As potential cast and wrought Mg alloys,Mg-X(X=Al,Zn,Sn)based alloys have attracted great interest.This work is to develop a dataset of atomic mobilities that is valid over a wide composition range.With the obtained mobilities,and a compatible thermodynamic description,as well as thermophysical parameters,simulations are performed to predict the characteristics of precipitation evolution.Examples are presented for the isothermal aging processes in Mg-x wt.%Al(x=5.9,6,8.8,9),Mg-x wt.%Zn(x=6,6.2,8,8.65),Mg-x wt.%Sn(x=6.04,6.92,8.64)alloys.The simulated size distribution,number density and volume fraction of precipitates reasonably account for the experimental results and provide additional information for further alloy composition design and heat treatment optimization.展开更多
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Y.Yang was supported by Research Grant Council(RGC),Hong Kong Government,through General Research Fund(RGC)(Nos.CityU11213118,CityU11200719 and CityU11209317).
文摘High corrosion resistance of alloys is essential for their structural applications;however,most alloys suffer from degradation of their corrosion resistance with the increasing acidity of their surround-ings.Nonetheless,we developed a series of medium-entropy alloys(MEAs)in this work,which ex-hibit high strength,superior fracture toughness and ultra-high corrosion resistance,outperforming the variety of corrosion resistant alloys hitherto reported.Most interestingly,our MEAs exhibit an unusual anti-corrosion behavior and their corrosion resistance increases with acidity in Cl−containing solutions.Through extensive thermodynamic calculations,density functional theory(DFT)simulations and experi-ments,we reveal that the unusual anti-corrosion behavior of our MEAs can be attributed to their surface chemical complexity,which facilitates the physio-chemical-absorption of H_(2)O and O_(2)and thus the rapid formation of metastable medium entropy passive films that contain the lowest amount of defects,as compared to the passive films on conventional alloys reported in the literature.
基金financially supported by the Major State Basic Research Development Program of China(No.2016YFB0701405)supported by the KTH-SJTU collaborative research and development seed grant in 2018,the Swedish Research Council(No.2019-04971)+2 种基金the Swedish Foundation for Strategic Research,the China Scholarship Council,the Swedish Energy Agency,the Hungarian Scientific Research Fund(No.research project OTKA 128229)the Fundamental Research Funds for the Central Universities(No.N180204015)The computation resource provided by the Swedish National Infrastructure for Computing(SNIC)at the National Supercomputer Centre in Linkoping,which is partially funded by the Swedish Research Council through grant agreement no.2018-05973。
文摘In order to efficiently explore the nearly infinite composition space in multicomponent solid solution alloys for reaching higher mechanical performance,it is important to establish predictive design strategies using computation-aided methods.Here,using ab initio calculations we systematically study the effects of magnetism and chemical composition on the generalized stacking fault energy surface(γ-surface) of Cr-Co-Ni medium entropy alloys and show that both chemistry and the coupled magnetic state strongly affect the γ-surface,consequently,the primary deformation modes.The relations among various stable and unstable stacking fault energies are revealed and discussed.The present findings are useful for studying the deformation behaviors of Cr-Co-Ni alloys and facilitate a density functional theory based design of transformation-induced plasticity and twinning-induced plasticity mechanisms in Cr-Co-Ni alloys.
基金financially supported by the National Key Research and Development Program of China(No.2016YFB0701202)the Innovation Foundation for Postgraduate and Fundamental Research Funds of Central South University(No.1053320182102)China Scholarship Council(No.201906370116)for the award of a fellowship and funding。
文摘As potential cast and wrought Mg alloys,Mg-X(X=Al,Zn,Sn)based alloys have attracted great interest.This work is to develop a dataset of atomic mobilities that is valid over a wide composition range.With the obtained mobilities,and a compatible thermodynamic description,as well as thermophysical parameters,simulations are performed to predict the characteristics of precipitation evolution.Examples are presented for the isothermal aging processes in Mg-x wt.%Al(x=5.9,6,8.8,9),Mg-x wt.%Zn(x=6,6.2,8,8.65),Mg-x wt.%Sn(x=6.04,6.92,8.64)alloys.The simulated size distribution,number density and volume fraction of precipitates reasonably account for the experimental results and provide additional information for further alloy composition design and heat treatment optimization.
