材料科学技术(英文版)2024，Vol.183Issue(16) ：63-71.DOI:10.1016/j.jmst.2023.10.025

Origin of the high propensity for nanoscale deformation twins in CrCoNi medium-entropy alloy

Nan-Jun Liu Zhang-Jie Wang Jun Ding Mark Asta Robert O.Ritchie Bin Gan Evan Ma Zhi-Wei Shan
材料科学技术(英文版)2024，Vol.183Issue(16) ：63-71.DOI:10.1016/j.jmst.2023.10.025
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Origin of the high propensity for nanoscale deformation twins in CrCoNi medium-entropy alloy

Nan-Jun Liu 1Zhang-Jie Wang 2Jun Ding 2Mark Asta 3Robert O.Ritchie 3Bin Gan 4Evan Ma 2Zhi-Wei Shan1
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作者信息

  • 1. Center for Advancing Materials Performance from the Nanoscale(CAMP-Nano),State Key Laboratory for Mechanical Behavior of Materials,Xi'an Jiaotong University,Xi'an 710049,China
  • 2. Center for Alloy Innovation and Design(CAID),State Key Laboratory for Mechanical Behavior of Materials,Xi'an Jiaotong University,Xi'an 710049,China
  • 3. Materials Sciences Division,Lawrence Berkeley National Laboratory,Berkeley,CA 94720,United States;Department of Materials Science & Engineering,University of California,Berkeley,CA 94720,United States
  • 4. Beijing Key Laboratory of Advanced High Temperature Materials,Central Iron and Steel Research Institute,Beijing 100081,China
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Abstract

Single-phase face-centered cubic(fcc)high/medium-entropy alloys(H/MEAs)exhibit a much higher ten-dency to form nanoscale deformation twins than conventional fcc metals with similar low stacking fault energies(SFEs).This extraordinary propensity for nanotwin formation in H/MEAs cannot therefore be ex-plained by their low SFEs alone.Here,using in situ compression tests of CrCoNi in comparison with Ag nanopillars inside a transmission electron microscope,we found that in the CrCoNi MEA,a high density of nanoscale twins continuously formed with an average thickness of 4.6 nm.In contrast,for similar ex-periments on Ag with almost identical SFE,following the nucleation of a few twins,they could further thicken to above one hundred nanometers by twin boundary migration.Molecular dynamics calculations indicated that in the highly-concentrated CrCoNi solid solution,the magnitude of the energy barriers for nucleating a stacking fault as a twin precursor in the pristine lattice and for the thickening of an existing twin both span a wide range and largely overlap with each other.Therefore,twin thickening through suc-cessive addition of atomic layers is prone to discontinuation,giving way to the nucleation of new twins at other sites where a lower energy barrier is encountered for partial-dislocation mediated fault formation.

Key words

High-entropy alloys/CrCoNi/Nanotwins/Twin nucleation

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基金项目

National Natural Science Foundation of China(52231001)

National Natural Science Foundation of China(51971167)

National Natural Science Foundation of China(52031011)

Xi'an Science and Technology Plan(2017xasjl014)

project from the Ministry of Science and Technology of China(2017YFA0700703)

National Natural Science Foundation of China(92060102)

CAID by XJTU()

National Natural Science Foundation of China(12004294)

HPC platform of Xi'an Jiaotong University()

Office of Science,Office of Basic Energy Sciences,Materials Sciences and Engineering Division,of the U.S.Department of Energ(DE-AC02-05-CH11231)

出版年

2024
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)

CSTPCD
影响因子：0.657
ISSN：1005-0302
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