Dynamic deformation behavior of a face-centered cubic FeCoNiCrMn high-entropy alloy  

作　　者：Junyang He Qi wang Husheng Zhang Lanhong Dai Toshiji Mukai Yuan Wu Xiongjun Liu Hui Wang Tai-Gang Nieh Zhaoping Lu 

机构地区：[1]State Key Laboratory for Advance Metals and Materials, University of Science and Technology Beijing, Beijing 100083, China [2]Max-Planck-Institut für Eisenforschung, Max-Planck-StraBe 1,D-40237 Dusseldorf, Germany [3]State Key Laboratory of Nonlinear Mechanics. Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China [4]China Ship Development and Design Center, Wuhan 430064, China [5]Department of Mechanical Engineering, Kobe University, 1-1, Rokkodai, Nada, Kobe 657-8501, Japan [6]Department of Materials Science and Engineering, The University of Tennessee, Knoxville, TN 37996,USA

出　　处：《Science Bulletin》2018年第6期362-368,共7页科学通报（英文版）

基　　金：supported by the National Natural Science Foundation of China(51671018,51531001,51422101,51371003,and 51671021);111 Project(B07003);International S&T Cooperation Program of China(2015DFG52600);Program for Changjiang Scholars and Innovative Research Team in University of China(IRT_14R05);the Projects of SKL-AMM-USTB(2016Z-04,2016-09,2016Z-16);the financial support from the Top-Notch Young Talents Program;the Fundamental Research Funds for the Central Universities;the financial support by US-NSF under contract DMR-1408722

摘　　要：In this study, mechanical tests were conducted oil a face-centered cubic FeCoNiCrMn high-entropy alloy, both in tension and compression, in a wide range of strain rates （10^-4-10^4 s^-1） to systematically investigate its dynamic response and underlying deformation mechanism. Materials with different grain sizes were tested to understand the effect of grain size, thus grain boundary volume, on the mechanical prop-erties. Microstructures of various samples both before and after deformation were examined using elec-tron backscatter diffraction and transmission electron microscopy. The dislocation structure as well as deformation-induced twins were analyzed and correlated with the measured mechanical properties. Plastic stability during tension of the current high-entropy alloy （HEA）, in particular, at dynamic strain rates, was discussed in lights of strain-rate sensitivity and work hardening rate. It was found that, under dynamic conditions, the strength and uniform ductility increased simultaneously as a result of the mas-sive formation of deformation twins. Specifically, an ultimate tensile strength of 734 MPa and uniform elongation of-63% are obtained at 2.3×10^3 s^-1, indicating that the alloy has great potential for energy absorption upon impact loading.In this study, mechanical tests were conducted on a face-centered cubic Fe Co Ni Cr Mn high-entropy alloy,both in tension and compression, in a wide range of strain rates(10^(-4)–10~4 s^(-1)) to systematically investigate its dynamic response and underlying deformation mechanism. Materials with different grain sizes were tested to understand the effect of grain size, thus grain boundary volume, on the mechanical properties. Microstructures of various samples both before and after deformation were examined using electron backscatter diffraction and transmission electron microscopy. The dislocation structure as well as deformation-induced twins were analyzed and correlated with the measured mechanical properties.Plastic stability during tension of the current high-entropy alloy(HEA), in particular, at dynamic strain rates, was discussed in lights of strain-rate sensitivity and work hardening rate. It was found that, under dynamic conditions, the strength and uniform ductility increased simultaneously as a result of the massive formation of deformation twins. Specifically, an ultimate tensile strength of 734 MPa and uniform elongation of $63% are obtained at 2.3 × 10~3 s^(-1), indicating that the alloy has great potential for energy absorption upon impact loading.

关 键 词：High-entropy alloys Dynamic deformation Deformation twinning Work-hardening Plastic stability 

分 类 号：TG139[一般工业技术—材料科学与工程]