Evolution of the spatial heterogeneity of metallic glasses and its correlation with the macroscopic visco-plasticity

• 主讲人：Xiaoding Wei (College of Engineering, Peking University)
• 举办方： Beijing-Moscow Mathematics Colloquium
• 时间： 2022-05-13 16:00 - 2022-05-13 17:00
• 地点： online

Recording: https://disk.pku.edu.cn:443/link/C48549B953F682393E90162B22FBE108
Valid Until: 2026-06-30 23:59

 

Abstract: Amorphous alloys (also known as metallic glasses) have no long-range order as crystalline counterparts, thus lacking traditional defects such as dislocations and grain boundaries to facilitate plastic deformation and strain hardening mechanisms. Instead, they have intrinsic hierarchical spatial heterogeneity inherited from the material preparation processes. More importantly, this spatial heterogeneity evolves with temperature and stress fields. In this study, we propose a chemo-mechanical constitutive law for metallic glasses that can describe the evolution of their spatial heterogeneity and establish the connection between this evolution with the macroscopic plastic deformation. Furthermore, our constitutive law reveals the underlying micro-mechanisms of metallic glasses under creep, relaxation, and fatigue.

 

Bio: Dr. Xiaoding Wei received his B.S. degree from the department of Modern Mechanics at University of Science and Technology of China in 2003, and Ph.D. degree from the department of Mechanical Engineering at Columbia University in 2009. Then, Dr. Wei worked as a postdoc researcher at Northwestern University until he joined the department of Mechanics and Engineering Science at Peking University in 2016. His research interests include the fundamental mechanics of low-dimensional materials, crystalline and amorphous metals, and bio-inspired materials. His achievements include measuring the intrinsic strength of monolayer graphene for the first time in the world. Dr. Wei has published 55 peer-reviewed papers in Science, Nature Communications, Journal of the Mechanics and Physics of Solids, etc.