Impact of gradient microstructure on strain hardening via activation of multiple deformation mechanisms in CoCrNi medium entropy alloy  

作　　者：Jiaqi Meng Yonghao Zhao Yi Liu Zongyao Li Bo Gao Mengning Xu Weiheng Xia Xuefei Chen Hao Zhou Yuntian Zhu 

机构地区：[1]Nano and Heterogeneous Materials Center,School of Materials Science and Engineering,Nanjing University of Science and Technology,Nanjing 210094,People’s Republic of China [2]School of Materials Science and Engineering,Hohai University,Chanazhou 213200,People’s Republic of China [3]Liaoning Academy of Materials,Shenyang 110167,People’s Republic of China [4]Department of Materials Science and Engineering,City University of Hong Kong,Hong Kong Special Administrative Region of China 999077,People’s Republic of China

出　　处：《Materials Futures》2024年第4期11-21,共11页材料展望（英文）

基　　金：supported by the National Key R&D Program of China(Grant No.2021YFA1200203);National Natural Science Foundation of China(Grant Nos.51931003,52071178 and 52201124);Jiangsu Province Leading Edge Technology Basic Research Major Project(BK20222014).

摘　　要：Face centered cubic(FCC)structural medium/high entropy alloys(MEAs),characterized by excellent strength and ductility,have attracted significant attention by the research community.The incorporation of gradient structures(GSs)further can enhance their mechanical properties.In the present research,we employ the rotation acceleration shot peening technique to introduce a GS within the CoCrNi FCC MEA to investigate underlying mechanisms governing the physical deformation processes during the generation of GSs through processing,which the primary goal is mitigating the intrinsic trade-off between strength and ductility.Through the microstructures analysis along the depth direction,both pre and post uniaxial tensile plastic deformation,we unveiled that the low stacking fault(SF)energy characteristic of the CoCrNi MEA triggered the emergence of diverse defects in the core region.The presence of nanoscale deformation twins,SFs,Lomer–Cottrell dislocation locks and phase transformation from FCC to hexagonal close-packed at twin boundaries synergistically enhanced the strain hardening capacity of the material.

关 键 词：CoCrNi MEA heterogeneous structure TWINNING phase transformation strain hardening 

分 类 号：TG14[一般工业技术—材料科学与工程]