|About this Abstract
||2022 TMS Annual Meeting & Exhibition
||First-principles Investigation of Early-stage Precipitation in Mg-Sn and Mg-Zn Alloys
||Du Cheng, Kang Wang, Bi-Cheng Zhou
|On-Site Speaker (Planned)
Mg-Sn and Mg-Zn alloys exhibit strong age-hardening effect and have become promising bases for high-strength and low-cost Mg alloys. However, the stoichiometries, atomic structures, phase stabilities, and formation mechanisms of the various nanoscale precipitates and intermetallic compounds during the heat treatment in these systems remain unclear. Here we use a combined approach of first-principles calculations, cluster expansion, and Monte Carlo simulation to investigate the atomic structures and thermodynamic stabilities of the experimentally reported precipitates as well as orderings on the FCC and HCP lattices in Mg-Sn and Mg-Zn alloys. The morphologies and formation mechanisms of precipitates are further inferred from the constituent strain energy analysis. In addition to the structure and stability of commonly observed compounds, potential Guinier-Preston (GP) zones are identified from preferred HCP orderings. Metastable phase diagrams with GP zones are constructed with both chemical and strain energy contributions which could help design better age-hardened Mg alloys.
||Magnesium, Modeling and Simulation, Phase Transformations