Interactions between [112] partial dislocations, interactions of vacancies and interstitials with partial dislocations, and self-diffusion along partial dislocations were studied by using a constant number of atoms, constant temperature and constant volume in molecular dynamics and many-atom models. The interaction energy between the partial dislocations was found to agree closely with the elastic continuum energy at the equilibrium separation distance and beyond. The former energy increased much more strongly at smaller separations, due to the increased core repulsion. This behavior indicated a small core overlap at equilibrium. A vacancy at the edge of a partial dislocation was found to have the form of a distorted hexagon, whereas an interstitial was found to form a long <110> crowdion in the (11¯1) plane in front of the edge of a partial dislocation, in Au or Cu. The self-diffusion activation energy for the vacancy mechanism was found to be at least 0.33eV lower than that for the interstitial mechanism in the region of the partial dislocation pair in Au. The corresponding activation energies were predicted to be equal in Cu. It was found that self-diffusion had almost equal components along the edges of the partial dislocations and stacking fault ribbon. It was suggested that this explained why self-diffusion in metals had a tendency to be weaker along partial dislocation pairs than along perfect dislocations.

J.Von Boehm, R.M.Nieminen: Physical Review B, 1996, 53[14], 8956-66