A hierarchical dislocation-grain boundary interaction model based on 3D discrete dislocation dynamics and molecular dynamics  

作　　者：GAO Yuan ZHUANG Zhuo YOU XiaoChuan 

机构地区：[1]Applied Mechanics Lab, School of Aerospace, Tsinghua University, Beijing 100084, China

出　　处：《Science China(Physics,Mechanics & Astronomy)》2011年第4期625-632,共8页中国科学：物理学、力学、天文学（英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant No. 10772096);the National Basic Research Program of China(Grand No. 2010CB631005)

摘　　要：We develop a new hierarchical dislocation-grain boundary （GB） interaction model to predict the mechanical behavior of poly- crystalline metals at micro and submicro scales by coupling 3D Discrete Dislocation Dynamics （DDD） simulation with the Molecular Dynamics （MD） simulation. At the microscales, the DDD simulations are responsible for capturing the evolution of dislocation structures; at the nanoscales, the MD simulations are responsible for obtaining the GB energy and ISF energy which are then transferred hierarchically to the DDD level. In the present model, four kinds of dislocafion-GB interactions, i.e. transmission, absorption, re-emission and reflection, are all considered. By this methodology, the compression of a Cu mi- cro-sized bi-crystal pillar is studied. We investigate the characteristic mechanical behavior of the bi-crystal compared with that of the single-crystal. Moreover, the comparison between the present penetrable model of GB and the conventional impenetrable model also shows the accuracy and efficiency of the present model.We develop a new hierarchical dislocation-grain boundary (GB) interaction model to predict the mechanical behavior of polycrystalline metals at micro and submicro scales by coupling 3D Discrete Dislocation Dynamics (DDD) simulation with the Molecular Dynamics (MD) simulation.At the microscales,the DDD simulations are responsible for capturing the evolution of dislocation structures;at the nanoscales,the MD simulations are responsible for obtaining the GB energy and ISF energy which are then transferred hierarchically to the DDD level.In the present model,four kinds of dislocation-GB interactions,i.e.transmission,absorption,re-emission and reflection,are all considered.By this methodology,the compression of a Cu micro-sized bi-crystal pillar is studied.We investigate the characteristic mechanical behavior of the bi-crystal compared with that of the single-crystal.Moreover,the comparison between the present penetrable model of GB and the conventional impenetrable model also shows the accuracy and efficiency of the present model.

关 键 词：Grain boundary Multiscale simulation Discrete dislocation dynamics Bi-crystal compression 

分 类 号：TG139.8[一般工业技术—材料科学与工程] TU435[金属学及工艺—合金]