Impact of lattice rotation on dislocation motion

TL;DR

This paper develops a phenomenological model for dislocation motion in two-dimensional lattices, incorporating local lattice rotation and defect densities, with specific results for square and hexagonal lattices.

Contribution

It introduces a new coarse-grained theoretical framework that explicitly accounts for lattice rotation and defect mobility anisotropy in dislocation dynamics.

Findings

Model includes local lattice orientation dependence.

Derives defect mobility equations with nonlocal dependence.

Provides specific results for square and hexagonal lattices.

Abstract

We introduce a phenomenological theory of dislocation motion appropriate for two dimensional lattices. A coarse grained description is proposed that involves as primitive variables local lattice rotation and Burgers vector densities along distinguished slip systems of the lattice. We then use symmetry considerations to propose phenomenological equations for both defect energies and their dissipative motion. As a consequence, the model includes explicit dependences on the local state of lattice orientation, and allows for differential defect mobilities along distinguished directions. Defect densities and lattice rotation need to determined self consistently and we show specific results for both square and hexagonal lattices. Within linear response, dissipative equations of motion for the defect densities are derived which contain defect mobilities that depend nonlocally on defect distribution.