Plasticity and Dislocation Dynamics in a Phase Field Crystal Model

TL;DR

This paper investigates dislocation avalanches in plastic flow using a phase field crystal model, revealing critical dynamics and confirming interface depinning behavior with mean field exponents.

Contribution

It introduces a PFC model where dislocations are generated naturally under shear, linking plasticity to interface depinning phenomena.

Findings

Dislocations are created, diffuse, interact, and annihilate, forming avalanches.

Event energy distributions collapse onto a universal curve across shear rates.

Critical exponents match mean field theory predictions.

Abstract

The critical dynamics of dislocation avalanches in plastic flow is examined using a phase field crystal (PFC) model. In the model, dislocations are naturally created, without any \textit{ad hoc} creation rules, by applying a shearing force to the perfectly periodic ground state. These dislocations diffuse, interact and annihilate with one another, forming avalanche events. By data collapsing the event energy probability density function for different shearing rates, a connection to interface depinning dynamics is confirmed. The relevant critical exponents agree with mean field theory predictions.