Atomistic Insights into the Competition between Damage and Dynamic Recrystallization Stimulated by the Precipitate Mg17Al12 in Magnesium Alloys

Abstract

Precipitates are closely related to ductile damage and dynamic recrystallization (DRX) in magnesium alloys. Using molecular dynamics simulation and the embedded atomic method, the competition between damage and DRX stimulated by the precipitate of magnesium alloys is investigated. The effects of precipitate distribution and dimensions on the void nucleation, dislocation emission, void growth, and DRX of magnesium alloys are quantitatively discussed. It is found that compared to the system with a pre-existing void, the system with a single precipitate has two extra stages during damage evolution, namely atomic disorder and void nucleation, and its strength is clearly better. Void growth is attributed to the dislocation emission from void tips. Keeping the same volume fraction and varying the dimensions and spacings of the precipitates, the results show that the refinement and densification can increase the deformation compatibility of the system, hindering void nucleation and elevating the toughness. This can be attributed to the reduction in stress concentration and the prevalence of the particle-stimulated DRX.