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

作     者：Nan-Jun Liu Zhang-Jie Wang Jun Ding Mark Asta Robert O.Ritchie Bin Gan Evan Ma Zhi-Wei Shan Nan-Jun Liu;Zhang-Jie Wang;Jun Ding;Mark Asta;Robert O.Ritchie;Bin Gan;Evan Ma;Zhi-Wei Shan

作者机构：Center for Advancing Materials Performance from the Nanoscale(CAMP-Nano)State Key Laboratory for Mechanical Behavior of MaterialsXi’an Jiaotong UniversityXi’an 710049China Center for Alloy Innovation and Design(CAID)State Key Laboratory for Mechanical Behavior of MaterialsXi’an Jiaotong UniversityXi’an 710049China Materials Sciences DivisionLawrence Berkeley National LaboratoryBerkeleyCA 94720United States Department of Materials Science&EngineeringUniversity of CaliforniaBerkeleyCA 94720United States Beijing Key Laboratory of Advanced High Temperature MaterialsCentral Iron and Steel Research InstituteBeijing 100081China 

出 版 物：《Journal of Materials Science & Technology》 (材料科学技术（英文版）)

年 卷 期：2024年第183卷第16期

页      面：63-71页

核心收录：

学科分类：08[工学] 080502[工学-材料学] 0805[工学-材料科学与工程（可授工学、理学学位）] 

基　　金：supported by the National Natural Science Foundation of China(Nos.52231001,51971167,and 52031011) the Xi’an Science and Technology Plan(No.2017xasjl014) B.G.gratefully acknowledges the financial support of the project from the Ministry of Science and Technology of China(No.2017YFA0700703) the support by the National Natural Science Foundation of China(No.92060102) E.M.and J.D.acknowledge the support at CAID by XJTU.J.D.acknowledges support from the National Natural Science Foundation of China(No.12004294) the HPC platform of Xi’an Jiaotong University supported by the Office of Science,Office of Basic Energy Sciences,Materials Sciences and Engineering Division,of the U.S.Department of Energy under Contract No.DE-AC02-05-CH11231 

主　　题：High-entropy alloys CrCoNi Nanotwins Twin nucleation 

摘      要：Single-phase face-centered cubic(fcc)high/medium-entropy alloys(H/MEAs)exhibit a much higher tendency 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 ***,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 *** contrast,for similar experiments 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 *** 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 ***,twin thickening through successive 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.