Coordinated grain boundary deformation governed nanograin annihilation in shear cycling

Yingbin Chen ¹Qishan Huang ²Qi Zhu ¹Kexing Song ³Yanjun Zhou ³Haofei Zhou ²Jiangwei Wang¹

扫码查看

作者信息

1. Center of Electron Microscopy and State Key Laboratory of Silicon Materials,School of Materials Science and Engineering,Zhejiang University,Hangzhou,310027,PR China
2. Center for X-Mechanics,Department of Engineering Mechanics,Zhejiang University,Hangzhou,310027,PR China
3. School of Materials Science&Engineering,Henan University of Science and Technology,Luoyang,471023,PR China
折叠

Abstract

Grain growth and shrinkage are essential to the thermal and mechanical stability of nanocrystalline metals,which are assumed to be governed by the coordinated deformation between neighboring grain boundaries(GBs)in the nanosized grains.However,the dynamics of such coordination has rarely been reported,especially in experiments.In this work,we systematically investigate the atomistic mechanism of coordinated GB deformation during grain shrinkage in an Au nanocrystal film through combined state-of-the-art in situ shear testing and atomistic simulations.We demonstrate that an embedded nanograin experiences shrinkage and eventually annihilation during a typical shear loading cycle.The continu-ous grain shrinkage is accommodated by the coordinated evolution of the surrounding GB network via dislocation-mediated migration,while the final grain annihilation proceeds through the sequen-tial dislocation-annihilation-induced grain rotation and merging of opposite GBs.Both experiments and simulations show that stress distribution and GB structure play important roles in the coordinated defor-mation of different GBs and control the grain shrinkage/annihilation under shear loading.Our findings establish a mechanistic relation between coordinated GB deformation and grain shrinkage,which reveals a general deformation phenomenon in nanocrystalline metals and enriches our understanding on the atomistic origin of structural stability in nanocrystalline metals under mechanical loading.

Key words

Nanocrystalline metals/Grain shrinkage and annihilation/Grain boundary migration/Grain rotation/Coordinated deformation

引用本文复制引用

基金项目

J.W.acknowledges the supports of the National Key Research and Development Program of China(2018YFB2000704)

National Natural Science Foundation of China(51771172)

National Natural Science Foundation of China(52071284)

and the Innovation Fund of the Zhejiang Kechuang New Materials Research Institute(ZKN-18-Z02)

H.Z.acknowledges financial support from the National Natural Science Foundation of China(11902289)

and computational support from the Super Cloud Computing Center in Beijing()

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86

段落导航