Atomistic dynamics of disconnection-mediated grain boundary plasticity:A case study of gold nanocrystals

查看全文 作　　者：Qi [1,2]Zhu;Haofei [3]Zhou;Yingbin [1]Chen;Guang [1]Cao;Chuang [4]Deng;Ze [1]Zhang;Jiangwei [1,2]Wang 机构地区：[1]Center of Electron Microscopy and State Key Laboratory of Silicon Materials,School of Materials Science and Engineering,Zhejiang University,Hangzhou 310027,China;[2]Wenzhou Key Laboratory of Novel Optoelectronic and Nano Materials,Institute of Wenzhou,Zhejiang University,Wenzhou 325006,China;[3]Center for X-Mechanics,Department of Engineering Mechanics,Zhejiang University,Hangzhou 310027,China;[4]Department of Mechanical Engineering,University of Manitoba,Winnipeg,MB R3T 5V6,Canada 出　　处：《Journal of Materials Science & Technology》索引2022年第30期,共10页 基　　金：support of the National Key R&D Program of China(No.2021YFA1200201);the National Natural Science Foundation of China(Nos.52071284 and 51771172);support from NSERC Discovery grant(No.RGPIN-05834-2019)。 摘　　要：Grain boundary(GB)mediated deformation is a vital contributor to the plasticity of polycrystalline materials,where the disconnection model has become a widely recognized approach to depict the GB dynamics.However,experimental understanding of the atomistic disconnection dynamics remains scarce.In this case study of gold nanocrystals,atomistic disconnection dynamics governing the shear-coupled migration of flat GBs have been systematically investigated via in situ transmission electron microscopy nanomechanical testing supported by molecular dynamics simulations.Specifically,the site-dependent nucleation,shear-driven propagation,and diverse interactions associated with distinct GB disconnections are systematically elucidated and quantitatively compared.Moreover,the disconnection-mediated GB plasticity proves to prevail among different tilt and mixed GBs in gold.Eventually,a conceptual map of disconnection-mediated GB dynamics is established,which would furnish a unified understanding of GB plasticity in metallic materials. 关 键 词：Grain boundaries(GBs) Disconnection dynamics Plastic deformation In situ transmission electron microscopy(TEM) Metallic materials