Interaction between deformation twinning and dislocation slip in polycrystalline solids

TL;DR

This paper develops a mesoscale model combining phase-field and crystal plasticity approaches to study the interaction between deformation twinning and dislocation slip in polycrystalline hcp metals, with implications for macroscopic behavior.

Contribution

It introduces a unified, GPU-accelerated model that captures twin and slip morphology, evolution, and interactions across multiple grains, advancing understanding of mesoscale deformation mechanisms.

Findings

Model effectively simulates twin-slip interactions in polycrystals.

GPU implementation enables fast, large-scale simulations.

Results inform how mesoscale phenomena influence bulk mechanical properties.

Abstract

Deformation twinning is a form of permanent deformation that is commonly observed in low symmetry crystals such as hexagonal close-packed (hcp) metals. With recent increased interest in using hcp metals, such as magnesium, in structural, automotive, and armor applications due to their high strength to weight ratio, there is a need for a comprehensive understanding of deformation twinning and its interaction with dislocation slip. A great deal has been learned at the microscopic level where individual dislocations interact with twin boundaries through atomistic simulations, and at the macroscopic level by ignoring morphology and treating twinning as `pseudo-slip'. However, twins form collectively across multiple grains with complex morphology that affects the bulk behavior. These mesoscale aspects have been less studied and are the focus of this paper. We present a model that describes the twin and slip morphology, its evolution, and interactions in a unified manner at the scale of several grains and use it to study the implications on macroscopic behavior. The key ideas are to combine a phase-field model of twinning with a crystal plasticity model of slip, and to implement it in parallel on graphic processing units for fast computations.