A crystal plasticity investigation of grain size-texture interaction in magnesium alloys

Abstract

This work investigates the microstructure-property linkages in magnesium (Mg) with an emphasis on understanding interaction effects between the grain size, texture, and loading orientation. A single crystal plasticity framework endowed with experimentally informed micro Hall-Petch type relations for the activation thresholds for slip and twinning is adopted to resolve polycrystalline microstructures over a broad texture-grain size space. The macroscopic trends from the simulations corroborate with experiments. The synergistic effects of microstructural engineering on the micromechanical characteristics are mapped, which reveal their role in the emergent macroscopic behaviors. The simulations predict reduced extension twinning with grain size refinement even though the micro Hall-Petch coefficient for twinning is smaller than that for the non-basal slip modes. While grain refinement and textural weakening generally reduce the net plastic anisotropy and tension-compression asymmetry, the degree to which these macroscopic behaviors are tempered depends on the loading orientation. The results offer preliminary insight into the roles that texture and grain size may play in the damage behavior of engineered Mg microstructures.