Various configurations of self-interstitial atoms, and their interaction with voids, were studied by using molecular dynamics methods. A pairwise interatomic potential was developed on the basis of pseudopotential theory. According to the results, the energetically preferable configurations of the self-interstitial atom were <111> dumb-bells and crowdions. The migration energies of these stable configurations along their axes were very small and did not exceed 0.01eV. It was shown that, under the stress field of a void nucleus containing 9 vacancies, a crowdion could migrate athermally and therefore be captured - by the void nucleus - from a considerably large distance. The form of the trajectory for crowdion athermal motion depended upon the orientation between the radius vector of the crowdion center, and its axis. Depending upon the crowdion axis orientation with respect to the void nucleus, 2- or 3-dimensional athermal motion of an interstitial took place. Modelling of crowdion interaction with a large void also showed that interaction between the crowdion and the elastic field of the void could cause its athermal motion, which resulted in crowdion capture by the void. The distance of attraction of a crowdion to a void could attain several void diameters.

Modelling of a Self-Interstitial Atom in α-Iron and its Interaction with Voids. A.A.Vasiliev, D.B.Mizandrontsev: Proceedings of the SPIE, 2000, 4064, 212-9