Interaction mechanisms of screw dislocations with {10(1)over-bar1} and {10(1)over-bar2} twin boundaries in Mg

Molecular dynamics simulations were carried out to investigate the interactions between screw partials and the {10 (1) over bar1} and {10 (1) over bar2} twin boundaries in Mg. In the {10 (1) over bar1} twin, the interaction was attractive and the partials were absorbed readily in the boundary. In the {10 (1) over bar2} twin, however, they passed through the {10 (1) over bar2} twin boundary because of a repulsive interaction when a large applied strain was applied. The total energy including the dislocation core energy and the twin boundary energy was found to be similar before and after the absorption of the partials in the {10 (1) over bar1} twin boundary, while it increased upon the absorption of the partial in the {10 (1) over bar2} twin boundary. The origins of the total energy variations are discussed from a crystallographic viewpoint.