Pipe diffusion along a dissociated edge dislocation was investigated. The formation energies of a vacancy and an interstitial in the cores and the fault ribbon were calculated by quasi-dynamics relaxation at 0K. The diffusion rates of these defects were calculated at high temperatures by counting the number of atomic jumps due to the migration of the defects. The variation in the diffusion coefficients with the inverse of the temperature yields the migration energies for pipe diffusion, and it was interesting to note that the value of the energy obtained for the interstitial was comparable with the bulk value. Contrary to current assumptions in favour of a vacancy mechanism, it was found that the two types of defect may contribute comparably with pipe diffusion since their activation energies were very close. Owing to the extension of the cores, the trajectories of the migrating defects involved not only the partials but also the stacking-fault ribbon. For this reason, pipe diffusion was slower when the dislocations were dissociated.

Migration of Point Defects Along a Dissociated Edge Dislocation in Copper. a Molecular Dynamics Study of Pipe Diffusion. Huang, J., Meyer, M., Pontikis, V.: Philosophical Magazine A, 1991, 63[6], 1149-65