Onset and Direction of Shear Banding Instability in Metallic Glasses

作     者：Yan Chen Lanhong Dai 

作者机构：State Key Laboratory of Nonlinear Mechanics Institute of Mechanics Chinese Academy of Sciences 

出 版 物：《Journal of Materials Science & Technology》 (材料科学技术（英文版）)

年 卷 期：2014年第30卷第6期

页      面：616-621页

核心收录：

学科分类：08[工学] 0817[工学-化学工程与技术] 0806[工学-冶金工程] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 0703[理学-化学] 0802[工学-机械工程] 0801[工学-力学（可授工学、理学学位）] 0702[理学-物理学] 

基　　金：Financial support is from the National Key Basic Research Program of China (Grant No. 2012CB937500) the National Natural Science Foundation of China (Grants Nos. 11202221 and 11132011) the CAS/SAFEA International Partnership Program for Creative Research Teams 

主　　题：Metallic glasses Shear banding instability Bifurcation 

摘      要：The shear banding instability occurs as the homogenous deformation in metallic glasses （MGs） develops to a critical point, at which the discontinuity in deformation rate is incipient across nano-scale shear bands. When and where the shear instability takes place is an important issue for understanding the shear band origin. However, such condition and direction of shear localization concerning the unique properties of MGs is still lacking for general stress state. In this paper, a new constitutive is introduced for MGs accounting for the pressure sensitivity, dilatancy and structural evolution; the shear banding is regarded as the appearance of instability in the constitutive description of inelastic deformation. Tying the bifurcation theory to the new constitutive, the general condition of deformation localization is derived. The shear band orientation corresponding to the easiest direction of shear instability is then obtained in dependence on pressure sensitivity, dilatancy and Poisson＇s ratio for MGs. The range of the predicted shear band angles is consistent with the experimental observations.