The effect of alloying elements on the dislocation climbing velocity in Ni: A first-principles study

By using density functional theory calculations in conjunction with the climbing images nudged elastic band method, the effects of alloying elements Re, W, Mo, Cr, Co and Ru on the velocity of dislocation climbing in gamma Ni were studied. The results shed a light on the mechanism of these elements suppressing the dislocation motion by connecting the stacking fault energy and the migration activation energy of vacancy with the dislocation climbing velocity. It is found that the elements can decrease the stacking fault energy of Ni and raise the migration activation energy of vacancy. The changes of these two energies result in the increase of the formation energy and the diffusion activation energy of the jog, thus the dislocation climbing is restricted. The results also reveal that the influences of alloying elements on dislocation climbing velocity depend on the characters of dislocations.