Interactions between twin boundary and point defects in magnesium at low temperature

摘要

The interactions between a {1012} twin boundary and point defects including vacancies and self-interstitial atoms in magnesium were investigated by molecular dynamics simulations at low temperature. The simulation results suggest that vacancies have a softening effect on TB migration, while interstitials lead to a hardening effect. During the interactions, vacancies were observed to be not absorbed by the TB. In contrast, interstitials are able to be absorbed by TB and migrate on TB. Finally, those absorbed interstitials aggregate and form interstitial clusters, which are released from the TB. The migration energies of vacancy and interstitial are calculated through nudged elastic band method. The aforementioned observations can be well explained by the migration energies, where the energies of a vacancy in a bulk crystal and on TB are both two order in magnitude higher than those of an interstitial. The current work provides new insights into the irradiation effects in magnesium.