报告题目：Atomistic simulation of grain boundary motion
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
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.