The interaction of vacancies with dislocations was studied by using the semi-discrete variational Peierls-Nabarro model and an ab initio determined γ-surface. For the first time theoretically, the so-called vacancy lubrication effect on dislocation motion in Al was confirmed, thus helping to resolve a long-standing controversy in the dislocation theory of face-centered cubic metals. Insights were obtained into the lubrication effect by exploring the relationship between dislocation mobility and core width. Increased dislocation splitting in the presence of vacancies was predicted. It was found that, on average, there was a weak repulsion between vacancies and dislocations which was independent of dislocation character.

Can Vacancies Lubricate Dislocation Motion in Aluminium? G.Lu, E.Kaxiras: Physical Review Letters, 2002, 89[10], 105501 (4pp)