Novel atomic-scale mechanism of incipient plasticity in a chemically complex CrCoNi medium-entropy alloy associated with inhomogeneity in local chemical environment

doi:10.1016/j.actamat.2020.05.042

IMECH-IR > 非线性力学国家重点实验室

	Novel atomic-scale mechanism of incipient plasticity in a chemically complex CrCoNi medium-entropy alloy associated with inhomogeneity in local chemical environment
	Cao FH(曹富华)1,2,3 ; Wang YJ(王云江)1,2,3 ; Dai LH(戴兰宏)1,2,3
发表期刊	ACTA MATERIALIA
	2020-08-01
卷号	194 页码:283-294
ISSN	1359-6454
摘要	Understanding the incipient plastic mechanism in metals is critical for their associated mechanical properties. While heterogeneous dislocation nucleation from pre-existing defects constitutes the most prevalent onset mechanism of plasticity in the conventional solutions, such a scenario may break down in the recently emerging chemically-disordered high/medium entropy alloys (HEAs/MEAs), owing to their unique multiple-component feature and the inevitable inhomogeneity in local atomic environments. Here, classical molecular dynamics simulations and first-principles density functional theory calculations are carried out to study the atomic-scale mechanisms governing the incipient plasticity in a prototypical chemically complex face-centered cubic (fcc) CrCoNi MEA. Dislocation nucleation is found to occur preferentially at an energetically unstable defect cluster with body-centered cubic like (bcc-like) atomic environment as a precursor, after certain deformation before plasticity, which is in contrast with the usual mechanism of heterogeneous dislocation nucleation in the conventional solute solution metals. The minimum energy pathway of dislocation nucleation from a bcc precursor is discussed to rationalize the usual phenomenon. First-principles athermal quasi-static compression test validates the mechanism suggested by atomistic simulations. Further electronic structure analysis suggests that the local bcc-like defect cluster is related to the localized electronic behaviors of Cr atoms and the weak Cr-Cr bonding, which promote the dislocation nucleation and therefore the incipient plasticity of CrCoNi MEA. The atomic and electronic insights reported here highlight the significant role of local chemical order in determining the mechanical property, and shed light on the strategy of optimizing mechanical performance via tailoring composition and local atomic arrangement in the generic highly concentrated solutions. (C) 2020 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
关键词	Dislocation nucleation Medium-entropy alloy Local chemical order Molecular dynamics Density functional theory
DOI	10.1016/j.actamat.2020.05.042
收录类别	SCI ; EI
语种	英语
WOS记录号	WOS:000542971400024
关键词[WOS]	SURFACE DISLOCATION NUCLEATION ; HYDROGEN EMBRITTLEMENT ; ACTIVATION VOLUME ; RATE SENSITIVITY ; SIZE DEPENDENCE ; DEFORMATION ; RESISTANCE ; ALUMINUM ; BEHAVIOR ; METALS
WOS研究方向	Materials Science ; Metallurgy & Metallurgical Engineering
WOS类目	Materials Science, Multidisciplinary ; Metallurgy & Metallurgical Engineering
项目资助者	NSFC Basic Science Center Program for ''Multiscale Problems in Nonlinear Mechanics''[11988102] ; NSFC[11790292] ; NSFC[11672299] ; National Key Research and Development Program of China[2017YFB0702003] ; National Key Research and Development Program of China[2017YFB0701502] ; Strategic Priority Research Program[XDB22040302] ; Strategic Priority Research Program[XDB22040303] ; Key Research Program of Frontier Sciences[QYZDJSSW-JSC011] ; Science Challenge Project[TZ2016001] ; Youth Promotion Association of Chinese Academy of Sciences[2017025] ; opening project of State Key Laboratory of Explosion Science and Technology[KFJJ18-14 M]
论文分区	一类
力学所作者排名	1
RpAuthor	Wang, Yun-Jiang ; Dai, Lan-Hong
引用统计	被引频次：97[WOS] [WOS记录] [WOS相关记录]
文献类型	期刊论文
条目标识符	http://dspace.imech.ac.cn/handle/311007/84736
专题	非线性力学国家重点实验室
作者单位	1.Chinese Acad Sci, Inst Mech, State Key Lab Nonlinear Mech, Beijing 100190, Peoples R China; 2.Univ Chinese Acad Sci, Sch Engn Sci, Beijing 101408, Peoples R China; 3.CAS Ctr Excellence Complex Syst Mech, Beijing 100190, Peoples R China
推荐引用方式 GB/T 7714	Cao FH,Wang YJ,Dai LH. Novel atomic-scale mechanism of incipient plasticity in a chemically complex CrCoNi medium-entropy alloy associated with inhomogeneity in local chemical environment[J]. ACTA MATERIALIA,2020,194:283-294.
APA	曹富华,王云江,&戴兰宏.(2020).Novel atomic-scale mechanism of incipient plasticity in a chemically complex CrCoNi medium-entropy alloy associated with inhomogeneity in local chemical environment.ACTA MATERIALIA,194,283-294.
MLA	曹富华,et al."Novel atomic-scale mechanism of incipient plasticity in a chemically complex CrCoNi medium-entropy alloy associated with inhomogeneity in local chemical environment".ACTA MATERIALIA 194(2020):283-294.

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