Interaction of Point Defects with Twin Boundaries in Copper

The interaction between small vacancy clusters and twin boundaries in copper is studied by using many-body potential developed by Ackland et al. for fcc metals. The interaction energies of single-, di- and tri-vacancy clusters with (111) and (112) twin boundaries are computed using well established simulation techniques. For (111) twins the vacancy clusters are highly repelled when they are on the adjacent planes, and are attracted when they are away from the boundary. In the case of (112) twins, vacancy clusters are more attracted to the boundary when they are near the boundary as compared to away from it. Vacancy clusters on both the sides of the boundary are also investigated, and it is observed that the clusters energetically preferto lie on the off-mirror sites as compared to the mirror position across the twin.