The atomic structures of interstitial-type dislocation loops, and interactions between these loops and an edge dislocation, were investigated by means of computer simulation in order to clarify the processes which were involved in cascade formation. Clusters of crowdions or dumb-bells were placed in the model lattice, and the final structures were observed after full relaxation. It was found that, in the case of clusters of crowdions, a splitting of the strain concentration for each crowdion in the cluster occurred upon increasing the number of crowdions. The splitting occurred when the number of crowdions exceeded about 10, and indicated a transition to dislocation loops. Study of the interaction between an initial cluster and an edge dislocation revealed that the stacking fault of an extended edge dislocation was heavily deformed by the presence of an interstitial cluster just below the slip plane. As the loop-size increased, the Peierls stress decreased and approached the level for a straight edge dislocation.

Computer Simulation of the Interaction between an Edge Dislocation and Interstitial Clusters in Fe and Ni. E.Kuramoto, K.Ohsawa, T.Tsutsumi, M.Koyanagi: Journal of Nuclear Materials, 1999, 271-272, 26-9