Phase field model for self-climb of prismatic dislocation loops by vacancy pipe diffusion

TL;DR

This paper introduces a phase field model for simulating the self-climb motion of prismatic dislocation loops driven by vacancy pipe diffusion, capturing complex topological changes and aligning well with experimental and discrete dislocation dynamics results.

Contribution

A novel phase field model based on the Cahn-Hilliard framework for accurately simulating dislocation self-climb including topological changes.

Findings

Model accurately predicts self-climb velocity in the sharp interface limit.

Simulations reproduce loop evolution, translation, coalescence, and repelling behaviors.

Results agree with discrete dislocation dynamics and experimental observations.

Abstract

In this paper, we present a phase field model for the self-climb motion of prismatic dislocation loops via vacancy pipe diffusion driven by elastic interactions. This conserved dynamics model is developed under the framework of the Cahn-Hilliard equation with incorporation of the climb force on dislocations, and is based on the dislocation self-climb velocity formulation established in Ref.[1]. The phase field model has the advantage of being able to handle the topological and geometrical changes automatically during the simulations. Asymptotic analysis shows that the proposed phase field model gives the dislocation self-climb velocity accurately in the sharp interface limit. Numerical simulations of evolution, translation, coalescence and repelling of prismatic loops by self-climb show excellent agreement with discrete dislocation dynamics simulation results and the experimental observation.