Thermal Effects in Dislocation Theory II: Shear Banding and Yielding Transitions

TL;DR

This paper applies thermodynamic dislocation theory to analyze shear banding and yielding transitions in polycrystalline solids, emphasizing the role of effective temperature and dislocation depinning in plastic deformation.

Contribution

It introduces a thermodynamic framework for understanding shear banding and yielding, linking effective temperature and dislocation depinning to plastic instability.

Findings

Shear banding instabilities are explained through thermodynamic dislocation theory.

Yielding transitions are interpreted as thermodynamic phase changes.

Effective temperature governs the onset of plastic deformation.

Abstract

The thermodynamic dislocation theory presented in preceding papers is used here to describe shear-banding instabilities. Central ingredients of the theory are a thermodynamically defined effective configurational temperature, and a formula for the plastic deformation rate determined by thermally activated depinning of entangled dislocations. An important feature of this paper is an interpretation of yielding transitions in polycrystalline solids.