Interstitial cluster motion in displacement cascades

Displacement cascades of energies up to 30 keV were investigated by molecular dynamics simulations in α-iron, nickel and in ordered intermetallic compounds Ni3Al. Different models of embedded-atom potentials were used in conjunction with a modification of the short-range repulsive interaction. Interstitial clusters were found to be very mobile at any size. The direction of the dumbbells in a cluster configuration was different as compared to that in an isolated configuration. A glide mechanism and a one-dimensional motion of these clusters were observed in different systems under investigation. Several types of cluster–cluster interactions have been observed: coalescence of two clusters with distinct glide cylinders assisted by the flip of the Burgers vector of one of the clusters, growth of a cluster by the absorption of isolated interstitials and elimination of vacancies swept by a large interstitial cluster. The migration trajectories and the diffusion coefficients of some clusters were investigated.