A Molecular dynamics study on the generation and gliding of a non-basal dislocation and its interaction with a twin boundary in magnesium

Kaburaki, Hideo; Itakura, Mitsuhiro  ; Yamaguchi, Masatake   ; Tsuru, Tomohito   

The generation of non-basal dislocations near the c-axis direction and the introduction of twin boundaries are the fundamental processes for enhancing plasticity in highly anisotropic hcp magnesium materials. Using the molecular dynamics method, we have successfully generated a c+a dislocation from the obstacle set in the perfect magnesium crystal by extending the material in the c-axis direction. A structure of the stacking fault is found to be corrugated and is extended indefinitely in the perfect crystal. The introduction of a twin boundary in the system enables the extended c+a dislocation to emit from the source and glide in the system. The interaction of a c+a dislocation or a basal dislocation with a twin boundary is found to be manifested in various results. A dislocation is absorbed in the twin boundary, and, in some condition, is reemitted from the boundary. The results of these interaction processes are assessed by simulating the systems in various configurations.