Molecular dynamics simulations of the interactions between screw dislocations and self-interstitial clusters in body-centered cubic Fe

Molecular dynamics simulations were performed to elucidate the interactions between screw dislocations and self-interstitial atom (SIA) defects in body-centered cubic Fe, using an embedded atom method potential fitted to ab initio forces. Two interaction mechanisms were identified: the junction mechanism, in which the original 1/2〈1 1 1〉 SIA loop was transformed into a 〈1 0 0〉 loop after the interaction, and the helical dislocation mechanism. The strengthening factor due to the interaction was estimated to be in the 0.4–0.6 range, in good agreement with experiments.