Enthalpy induced phase partition toward hierarchical,nanostructured high-entropy alloys

作     者：Rong Guo Lanlan Yu Zhenyu Liu Jie Pan Yonggang Yao Lin Liu Rong Guo;Lanlan Yu;Zhenyu Liu;Jie Pan;Yonggang Yao;Lin Liu

作者机构：State Key Laboratory of Materials Processing and Die&Mould TechnologySchool of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074China 

出 版 物：《Nano Research》 (纳米研究（英文版）)

年 卷 期：2022年第15卷第6期

页      面：4893-4901页

核心收录：

学科分类：08[工学] 080502[工学-材料学] 0805[工学-材料科学与工程（可授工学、理学学位）] 

基　　金：supported by the National Natural Science Foundation of China(Nos.52061160483 52022100 and 52101255) 

主　　题：nanocrystalline high-entropy alloys enthalpy hierarchical structures coherent precipitates 

摘      要：Heterogeneous nanostructured metals are emerging strategies for achieving both high strength and ductility,which are particularly attractive for high entropy alloys(HEAs)to combine the synergistic enhancements from multielement composition,grain boundaries,and heterogeneity ***,the construction of heterogeneous nanostructured HEAs remains elusive and can involve delicate processes that are not practically *** we report using composition design(i.e.,enthalpy engineering)to create hierarchical,nanostructured HEAs as demonstrated by adding Ni into FeCrCoAlTi_(0.5)*** strong enthalpic interaction between(Ni,Co)and(Al,Ti)pairs in FeCrCoAlTi_(0.5)Nix(x=0.5–1.5)induced phase partitions into B2(ordered phase,hard)matrix and A2(disordered phase,soft)precipitates,resulting in a hierarchical structure of B2 grains and sub-grains of near-coherent A2 nanodomains(~12.5 nm)divided by A2 interdendritic *** a result,the FeCrCoAlTi_(0.5)Ni_(0.5)HEA with this unique hierarchical nanostructure exhibits the best combination of strength and plasticity,i.e.,a 2-fold increase in compressive strength(2.60 GPa)and significant enhancement of plastic strain(15.8%)as compared with the original FeCrCoAlTi_(0.5)*** analysis and simulation study reveal the phase partition process during cooling induced by an enthalpy-driven order-disorder transition while the order parameters illustrate the strong ordering in(Ni,Co)(Al,Ti)-rich B2 phase and high entropy mixing in less interactive FeCrCo-rich A2 *** work therefore provides a strategy for hierarchical nanostructured HEA formation by composition design considering enthalpy and entropy interplay.