Atomistic Investigation of the Effect of Non-Glide Stress on the Deformation and Dislocation Transfer at Hexagonal Close-Packed Metal Grain Boundary

Abstract

Abstract The molecular dynamics method was utilized in this study to investigate the dislocation transfer mechanism at the atomic scale at basal and prismatic (BP) boundaries in Magnesium. Firstly, uniaxial deformation (pre-tensile and pre-compression) is dynamically applied at the BP interface. The results demonstrate that when plastic deformation increases, there is a remarkable change in the structure of the BP interface. Furthermore, the interaction mechanism between the BP interface and basal dislocations (edge and screw) was observed. The results show that for the basal and the prismatic slip when the Burgers vector is aligned in a direction that is perpendicular to the interface, a basal dislocation is transmuted to a prismatic dislocation and vice versa. The critical resolved shear stress for first basal screw dislocation transmutation is considerably higher than edge dislocation. The pre-normal strain and temperature analyses for the BP interface were also performed to understand the interactions’ mechanism better. As the pre-tensile strain increases, the maximum critical resolved shear stresses to initiate basal edge and screw dislocation transmutation through the BP interface are progressively reduced. In contrast, when the pre-compression strain increases, the maximum critical resolved shear stresses increase.