Disclination-Based Crystal Plasticity FE Analysis for Influence of Kink Formation and Grain Size on Material Strength in Dual-Phase Mg Alloy with LPSO Phase

Abstract

Dual-phase Mg alloys consisting of α-Mg phase and LPSO phase are attracting attention as structural materials of next-generation because of its high specific strength and relatively high ductility. These alloys have excellent mechanical properties attributed to kink deformation and grain refinement based on dynamic recrystallization. However, the influence of kink formation and difference in grain size on material strength of the alloys has never been clarified computationally. In this paper, a crystal plasticity Cosserat model is newly developed considering disclination density to take account of information of rotational crystal defect important for kink formation. Using the preset model, a two-dimensional FE analysis is performed for a rectangular three-crystal plate and a polycrystalline plate of the dual-phase Mg alloys with LPSO phase. Through such computation, the effects of shape of kink band and recrystallized grain size of α-Mg phase on change in material strength are numerically predicted in the process of reverse loading after compression one.