Molecular dynamics simulations on the interactions between basal edge dislocation and point defects in magnesium at low temperature

DF Li and J Tang and XB Tian and QY Wang and WT Jiang and HD Fan, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS, 510, 20-28 (2022).

DOI: 10.1016/j.nimb.2021.10.019

In this work, we performed molecular dynamics (MD) simulations on the interactions between a basal edge a dislocation and point defects including vacancies and self-interstitial atoms in magnesium. Simulation results suggest that both self-interstitial atoms and vacancies have a blocking effect on dislocation motion, but the blocking effect of vacancies is much weaker than that of self-interstitial atoms. During interactions, selfinterstitial atoms are absorbed and move with dislocation, and the edge dislocation climbs after absorbing self- interstitial atoms. In contrast, vacancies cannot be absorbed. To explain these observations, the binding energy and migration energy are calculated. The binding energy of both vacancies and self-interstitial atoms increases as they approach the dislocation core, seemingly indicating that they can be absorbed. However, the migration barrier of a vacancy is found to be about two orders in magnitude higher than that of a self-interstitial atom. Therefore, only self-interstitial atoms are absorbed, while vacancies cannot.

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