报告题目：Atomistic simulation of grain boundary motion

报告人：Chuang Deng教授，加拿大曼尼托巴大学

时间：2017年5月23日下午1:00

地点：徐祖耀楼500号

联系人：祝国珍老师

报告人简介：

1999-2003      B.S. in Materials Physics, Fudan University

2005-2009      Ph.D. in Materials Science, the University of Vermont, USA

2010-2012      Postdoc at MIT, USA

    2012-2016      Assistant professor, Department of Mechanical Engineering, the University of Manitoba, Canada

    2016-present Associate Professor, Department of Mechanical Engineering, the University of Manitoba, Canada

摘要:

The physical properties of materials highly depend on their grain size and many novel properties emerge when the grain size reduces to the nanometer scale. However, nanocrystalline materials are generally unstable and suffer from rapid grain growth via the motion of grain boundaries when exposed to high temperature or mechanical deformation, which poses great challenge to maintain their superior properties over their coarse-grained counterparts during thermal processing or service. In this work, molecular dynamics simulations were used to investigate grain boundary motion driven by both thermal and mechanical effects. In particular, the impurity effects on thermally grain boundary motion was quantified, which was the first attempt through molecular dynamics simulations. On the other hand, shear coupled grain boundary motion with the presence of constraints such as void and crack was investigated. An interesting crack-healing was found during the crack-grain boundary interaction and a mechanism based on grain boundary structural transformation was proposed to explain the observed unusual crack healing.