Local chemical inhomogeneities in TiZrNb-based refractory high-entropy alloys  

作　　者：Kaihui Xun Bozhao Zhang Qi Wang Zhen Zhang Jun Ding En Ma 

机构地区：[1]Center for Alloy Innovation and Design(CAID),State Key Laboratory for Mechanical Behavior of Materials,Xi’an Jiaotong University,Xi’an 710049,China [2]Science and Technology on Surface Physics and Chemistry Laboratory,P.O.Box 9-35,Jiangyou 621908,China

出　　处：《Journal of Materials Science & Technology》2023年第4期221-230,共10页材料科学技术（英文版）

基　　金：J.D.and E.M.acknowledge XJTU for hosting their research at the Center for Alloy Innovation and Design(CAID).This work was funded by the Natural Science Foundation of China(No.12004294);National Youth Talents Program and the HPC platform of Xi’an Jiaotong University。

摘　　要：Multi-principal element solid solutions are prone to develop local chemical inhomogeneities,i.e.,chemi-cal order/clustering and/or compositional undulation.However,these structural details from short-range(first couple of nearest-neighbor atomic shells)to nanometer length scale are very challenging to re-solve in both experimental characterization and computer simulations.For instance,Monte Carlo model-ing based on density-functional-theory calculations is severely limited by the sample size and the sim-ulation steps practical in the simulations.Adopting the cluster expansion approach,here we systemati-cally reveal the local chemical inhomogeneity,including chemical order and compositional fluctuation,in three representative equiatomic TiZrNb-based body-centered cubic refractory high-entropy alloys(HEAs):TiZrNb,TiZrHfNb and TiZrHfNbTa.Ti-Zr pairs are found to exhibit the highest degree of chemical pref-erence among all atomic pairs.Such chemical short-range order(CSRO)induces an accompanying com-positional undulation,both extending to characteristic dimensions of the order of one nanometer.The chemical inhomogeneity trend uncovered for this series of TiZrNb-based HEAs is expected to impact their mechanical properties;e.g.,incorporating the CSRO effects in a current model significantly improves its agreement with experimental measured yield strength.

关 键 词：Local chemical inhomogeneity Cluster expansion TiZrNb-based high-entropy alloy Chemical short-range order Compositional fluctuation 

分 类 号：TG139[一般工业技术—材料科学与工程]