Phase-Field Modeling of Deformation Twinning and Dislocation Slip Interaction in Polycrystalline Solids

Abstract

Mechanical twinning is a form of inelastic deformation in magnesium and other hexagonal close-packed (hcp) metals, which has a significant effect on material behavior. Magnesium's high strength-to-weight ratio has led to its interest in structural, automotive, and armor applications, requiring a comprehensive understanding of twinning's effect on material response. Past studies have taken either a microscopic approach, through atomistic simulations, or a macroscopic approach, through simplified pseudo-slip models. However, twins interact across the mesoscale, forming collectively across grains with complex local morphology propagating into bulk behavior. With the goal of describing twinning's mesoscale behavior, we propose a model where twinning is treated using a phase-field approach, while slip is considered using crystal plasticity, with lattice reorientation, twinning length scale, and twin-slip interactions all accounted. We present GPU accelerated simulations on polycrystalline solids and summarize the insights gained from these studies and the implications on the macroscale behavior of hcp materials.

Additional details