Refractory high-entropy alloys with ultra-high strength and strain hardening ability induced by heterogeneous deformation and microbands  

作　　者：Yaxi Ma Yang Zhang Lixin Sun Zhongwu Zhang 

机构地区：[1]Key Laboratory of Superlight Materials and Surface Technology,Ministry of Education,College of Materials Science and Chemical Engineering,Harbin Engineering University,Harbin 150001,China

出　　处：《Journal of Materials Science & Technology》2024年第25期215-227,共13页材料科学技术(英文版)

基　　金：supported by the NSFC Funding(Nos.U2141207,52001083,and 52171111);the Natural Science Foun-dation of Heilongjiang(No.YQ2023E026);the Youth Talent Project of China National Nuclear Corporation(No.CNNC2021YTEP-HEU01).

摘　　要：Refractory high-entropy alloys(RHEAs)are potential materials for high-temperature structural applica-tions due to their excellent high-temperature performance.However,the early onset of plastic instability in RHEAs is a critical issue to be addressed.In this study,a novel Zr35 Ti30 Nb20 Al10 V5 RHEA was subjected to 95%cold rolling and annealing,achieving outstanding mechanical properties.Notably,the cold-rolled alloy exhibited the highest reported tensile strength(∼2.0 GPa)among RHEAs with a moderate ductil-ity of∼8.5%.Moreover,Additionally,the subsequent annealing process enabled the alloy to achieve an outstanding combination of yield strength(1.1 GPa)and fracture elongation(20%).The cold-rolled alloy has a heterogeneous lamella structure with high-density dislocation cells and dislocation pile-ups,and lattice distortion in the locally chemically ordered structure.The high work hardening behavior origi-nates from the heterogeneous deformation-induced(HDI)hardening,which makes the HDI stress and hardening rate increase with increasing strain.In the annealed alloy,lattice distortion increases signifi-cantly with increasing strain,promoting dislocation cross-slip.The dislocation pile-ups and interactions facilitate the transition of microbands,and the relatively stable work-hardening behavior of the alloy is mainly attributed to the microband-induced plasticity effect.This study provides novel insights into the design and optimization of highly formable RHEAs with excellent mechanical properties.

关 键 词：Refractory high-entropy alloy Severe plastic deformation Heterogeneous structure Heterogeneous deformation-induced hardening Microband-induced plasticity 

分 类 号：TG1[金属学及工艺—金属学]