Hierarchical grain size and nanotwin gradient microstructure for improved mechanical properties of a non-equiatomic CoCrFeMnNi high-entropy alloy

Zibing An ¹Shengcheng Mao ¹Yinong Liu ²Hao Zhou ³Yadi Zhai ¹Zhiyong Tian ¹Cuixiu Liu ¹Ze Zhang ⁴Xiaodong Han¹

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作者信息

1. Beijing Key Lab of Microstructure and Property of Advanced Materials,Faculty of Materials and Manufacturing,Beijing University of Technology,Beijing 100124,China
2. Department of Mechanical Engineering,The University of Western Australia,Perth,WA 6009,Australia
3. Nano and Heterogeneous Structural Materials Center,School of Materials Science and Engineering,Nanjing University of Science and Technology,Nanjing 210094,China
4. Beijing Key Lab of Microstructure and Property of Advanced Materials,Faculty of Materials and Manufacturing,Beijing University of Technology,Beijing 100124,China;State Key Laboratory of Silicon Materials,Department of Materials Science and Engineering,Zhejiang University,310058 Hangzhou,China
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Abstract

This study explored a multi-mechanism approach to improving the mechanical properties of a CoCr-FeMnNi high-entropy alloy through non-equiatomic alloy design and processing.The alloy design en-sures a single-phase face-centered cubic structure while lowering the stacking fault energy to encour-age the formation of deformation twins and stacking faults by altering the equiatomic composition of the alloy.The processing strategy applied helped create a hierarchical grain size gradient microstructure with a high nanotwins population.This was achieved by means of rotationally accelerated shot peen-ing(RASP).The non-equiatomic CoCrFeMnNi high-entropy alloy achieved a yield strength of 750 MPa,a tensile strength of 1050 MPa,and tensile uniform elongation of 27.5％.The toughness of the alloy was 2.53×1010 kJ/m3,which is about 2 times that of the same alloy without the RASP treatment.The strength increase is attributed to the effects of grain boundary strengthening,dislocation strengthening,twin strengthening,and hetero-deformation strengthening associated with the heterogeneous microstruc-ture of the alloy.The concurrent occurrence of the multiple deformation mechanisms,i.e.,dislocation deformation,twining deformation and microband deformation,contributes to achieving a suitable strain hardening of the alloy that helps to prevent early necking and to assure steady plastic deformation for high toughness.

Key words

High entropy alloy/Gradient and hierarchical structure/Mechanical property/Deformation mechanism

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基金项目

Basic Science Center Program for Multiphase Evolution in Hyper-gravity of the National Natural Science Foundation of China(51988101)

NSFC programs(52071003)

NSFC programs(91860202)

NSFC programs(11604006)

Beijing Munici-pal Education Commission Project(PXM2020_014204_000021)

Beijing Munici-pal Education Commission Project(PXM2019_014204_500032)

Beijing Outstanding Young Scientists Projects(BJJWZYJH01201910005018)

Beijing Natural Science Foundation(Z180014)

"111"project(DB18015)

Australian Research Council(DP190102990)

出版年

2021

材料科学技术(英文版)

中国金属学会中国材料研究学会中国科学院金属研究所

材料科学技术(英文版)

CSTPCDCSCDSCI

影响因子：0.657

ISSN：1005-0302

参考文献量62

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