Effect of twin boundaries on nanovoid growth based on dislocation emission

A theoretical model to describe the growth of nanovoid in nanotwinned materials was proposed in this paper. In the framework of the model, dislocations emitted from the surface of the void were subjected to four stresses: the local stress generated by applied stress, the image stress at the place of the dislocation exerted by the free surface of the nearby void, the lattice friction stress and the stress from the previously emitted dislocations. The surface effect was taken into consideration. The critical stress required for dislocation emission as a function of the void radius and the maximum number of edge dislocations emitted from the surface of the void as a function of the twin lamellae thickness were calculated. The critical stress as well as the maximum number was also analyzed for various angles between loading axis and twin boundary. In addition, the effects of the twin lamellae thickness and the angle between loading axis and twin boundary on the damage process of nanotwinned materials were discussed.