Modeling of a self-interstitial atom in α-iron and its interaction with voids

摘要

Different configurations of self-interstitial atoms (SIA) inα-iron and their interaction with the voids have been studied by molecular dynamics method. Pairwise interatomic potential was calculated on the basis of pseudopotential theory. According to the results obtained, the most energetically preferable configurations of the SIA are <111> dumb-bell and crowdion. Migration energies of these stable configurations along their axis are very small and do not exceed 0.01 eV. It was shown that under the stress field of the void nucleus, containing 9 vacancies, crowdion may athermally migrate and, as a result, be captured by the void nucleus from considerably large distance. The form of the trajectory for crowdion athermall motion depends on the orientation between radius vector of the crowdion center and its axis. In dependence on the crowdion axis orientations in relation to the void nucleus, two- or three-dimensional athermal motion of an interstitial takes place. Modeling of crowdion interaction with a large void additionally has shown that the interaction between the crowdion and elastic field of the void can cause its athermal motion, which resulted in the crowdion capture by the void. The distance of such a (pulling>) of a crowdion into a void can reach several diameters of the void.