Dislocation in Motion as the Dynamic Distribution of Elastic Field Singularity

TL;DR

This paper introduces a novel model representing dislocation motion as a dynamic elastic field singularity distribution, revealing insights into dislocation energetics and the influence of surrounding elastic regions.

Contribution

The paper presents a new approach to model dislocation motion by treating it as a dynamic elastic field singularity distribution, capturing energetics and barrier effects.

Findings

Model exhibits energetics similar to dislocation in Peierls barrier

Singularity distribution results from external shear stress

Elastic region around core significantly affects potential barrier

Abstract

Plastic deformation of crystals is a physical phenomenon, which has immensely driven the development of human civilisation since the onset of the Chalcolithic period. This process is primarily governed by the motion of line defects, called dislocations. Each dislocation traps a quantum of plastic deformation expressible in terms of its Burgers vector[1,2]. Theorising the mechanisms of dislocation motion at the atomistic scales of length and time remains a challenging task on account of the extreme complexities associated with the dynamics. We present a new concept of modelling a moving dislocation as the dynamic distribution of the elastic field singularity within the span of the Burgers vector. Surprisingly, numerical implementation of this model for the periodic expansion-shrinkage cycle of the singularity is found to exhibit an energetics, which resembles that of a dislocation moving in the presence of the Peierls barrier[1-4]. The singularity distribution is shown to be the natural consequence under the external shear stress. Moreover, in contrast to the conventional assumption, here the calculations reveal a significant contribution of the linear elastic region surrounding the core towards the potential barrier.