10-12 twin boundaries migration accompanied by void in magnesium

CL Xu and L Yuan and DB Shan and B Guo, COMPUTATIONAL MATERIALS SCIENCE, 184, 109857 (2020).

DOI: 10.1016/j.commatsci.2020.109857

Grain boundary (GB) migration plays a vital role in the plastic deformation of nanopolycrystalline metals. Molecular dynamics (MD) simulation on a bicrystalline Mg model is employed to investigate the mechanism of basal-prismatic (BP) boundary migration. Furthermore, a cylindrical void is inserted in the grain or at BP boundary to study its influence on the boundary migration. The results show the BP boundary migration might be hindered by void with parts of GB pinned at the intersection. The location of void can affect the start position of BP boundary migration. For intergranular void, due to the heterogeneous nucleation, the BP boundary migration always starts at the junction between void and boundary. For intragranular void, due to the attraction from void to GB dislocation, BP boundary migration always start at one side of void and tends to move towards the void. As the void size increases, the yield stress of BP boundary migration will be reduced.

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