文献类型：期刊文献

英文题名：Dislocation structure and dynamics govern pop-in modes of nanoindentation on single-crystal metals

作者：Zhou, Nian Elkhodary, Khalil I. Huang, Xiaoxu Tang, Shan Li, Ying

第一作者：周念

通信作者：Tang, S[1];Li, Y[2];Li, Y[3]

机构：[1]Guizhou Inst Technol, Sch Mat & Met Engn, Guiyang, Guizhou, Peoples R China;[2]Amer Univ Cairo, Dept Mech Engn, New Cairo, Egypt;[3]Dalian Univ Technol, State Key Lab Struct Anal Ind Equipment, Res Ctr Computat Mech, Dept Engn Mech, Dalian, Peoples R China;[4]Univ Connecticut, Inst Mat Sci, Dept Mech Engn, Storrs, CT 06269 USA;[5]Univ Connecticut, Inst Mat Sci, Polymer Program, Storrs, CT 06269 USA

第一机构：贵州理工学院材料与冶金工程学院

通信机构：corresponding author), Dalian Univ Technol, State Key Lab Struct Anal Ind Equipment, Res Ctr Computat Mech, Dept Engn Mech, Dalian, Peoples R China;corresponding author), Univ Connecticut, Inst Mat Sci, Dept Mech Engn, Storrs, CT 06269 USA;corresponding author), Univ Connecticut, Inst Mat Sci, Polymer Program, Storrs, CT 06269 USA.

年份：2020

卷号：100

期号：12

起止页码：1585-1606

外文期刊名：PHILOSOPHICAL MAGAZINE

收录：;EI(收录号：20201208306178);Scopus(收录号：2-s2.0-85081604583);WOS:【SCI-EXPANDED(收录号:WOS:000519716900001)】；

基金：LThis work was supported by the National Natural Science Foundation of China (NSFC) [grant numbers 11472065 and 11872139].

语种：英文

外文关键词：Nanoindentation; pop-in; dislocation; molecular dynamics simulation

摘要：There are two types of pop-in mode that have been widely observed in nanoindentation experiments: the single pop-in, and the successive pop-in modes. Here we employ the molecular dynamics (MD) modelling to simulate nanoindentation for three face-centred cubic (FCC) metals, including Al, Cu and Ni, and two body-centred cubic (BCC) metals, such as Fe and Ta. We aim to examine the deformation mechanisms underlying these pop-in modes. Our simulation results indicate that the dislocation structures formed in single crystals during nanoindentation are mainly composed of half prismatic dislocation loops. These half prismatic dislocation loops in FCC metals are primarily constituted of extended dislocations. Lomer-Cottrell locks that result from the interactions between these extended dislocations can resist the slipping of half dislocation loops. These locks can build up the elastic energy that is needed to activate the nucleation of new half dislocation loops. A repetition of this sequence results in successive pop-in events in Al and other FCC metals. Conversely, the half prismatic dislocation loops that form in BCC metals after first pop-in are prone to slip into the bulk, which sustains plastic indentation process after first pop-in and prevents subsequent pop-ins. We thus conclude that pop-in modes are correlated with lattice structures during nanoindentation, regardless of their crystal orientations.