An unprecedented synergy of high-temperature tensile strength and ductility in a NiCoCrAlTi high-entropy alloy

作     者：Zhang, Hongmin Meng, Fanchao Meng, Haoyan Tong, Yang Liaw, Peter K. Yang, Xiao Zhao, Lei Wang, Haizhou Gao, Yanfei Chen, Shuying 

作者机构：Institute for Advanced Studies in Precision Materials Yantai University Shandong Yantai264005 China Department of Materials Science and Engineering The University of Tennessee KnoxvilleTN37996 United States Key Laboratory of Cryogenics Technical Institute of Physics and Chemistry Chinese Academy of Sciences Beijing100190 China Beijing Advanced Innovation Center for Materials Genome Engineering Beijing Key Laboratory of Metal Materials Characterization Central Iron and Steel Research Institute Beijing100081 China 

出 版 物：《arXiv》 (arXiv)

年 卷 期：2023年

核心收录：

主　　题：Stacking faults 

摘      要：The present work reported a novel L12-strengthening NiCoCrAlTi high entropy alloy (HEA) with an outstanding synergy of tensile strength and ductility at both ambient and high temperatures. Transmission electron microscopy (TEM) characterization revealed a high density of rod-like and spheroidal L12 precipitates distributing in the micro/nanograins and non-recrystallized regions in the annealed specimens. The tremendously high yield stress, ultimate tensile stress (UTS), and ductility of the HEA at 600 °C were ~1060 MPa, 1271 MPa, and 25%, respectively, which were significantly superior to most reported HEAs and Co- and Ni-based superalloys to date. Systematic TEM analysis unveiled that the cooperation among L12 precipitation, extensive stacking faults (SFs), deformation twins (DTs), immobile Lomer-Cottrell (L-C) locks formed from interactions between SFs and SFs/DTs, hierarchical SFs/DTs networks, as well as hetero-deformation-induced strengthening dominated the plastic deformation at 600 °C. Such a unique deformation mechanism enabled extremely high tensile strength and sustained ductility of the HEA at a high temperature. © 2023, CC BY-NC-ND.