Nucleation kinetics of the beta'' precipitate in dilute Mg-Y alloys: A kinetic Monte Carlo study

HT Liao and H Kimizuka and A Ishii and JP Du and S Ogata, SCRIPTA MATERIALIA, 210, 114480 (2022).

DOI: 10.1016/j.scriptamat.2021.114480

The beta'' precipitate is a primary strengthening precipitate in Mg-Y alloys. It nucleates as localized zigzag and hexagonal-shaped clusters. Studies on the nucleation kinetics of beta'' precipitate are scarce. In this study, we applied the kinetic Monte Carlo (KMC) approach to explore the nucleation kinetics of the beta'' precipitates in the Mg-3.0 at.%Y system using a density functional theory-based interatomic potential. The time evolution of nucleation of the beta'' precipitates was characterized based on the KMC results. Using these results, we predicted the existence of an optimum temperature for the formation of the beta'' precipitates to be 550 K, at which the time necessary for nucleation is the shortest. Moreover, an upper temperature limit, above which the beta'' precipitates cannot nucleate, was computed as 700 K. This study explains precipitate nucleation in Mg-Y alloys at an atomic level and provides the theory for obtaining an optimal age-hardening response. (C)& nbsp;2021 The Authors. Published by Elsevier Ltd on behalf of Acta Materialia Inc.

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