Thermodynamic theory of dislocation/grain boundary interaction

TL;DR

This paper develops a thermodynamic framework to understand how dislocations interact with grain boundaries, affecting plastic deformation and work hardening in polycrystals, considering different boundary conditions.

Contribution

It introduces a thermodynamic theory for dislocation-grain boundary interactions, analyzing various boundary conditions and their effects on work hardening in bicrystals.

Findings

Impermeable grain boundaries hinder dislocation transfer.

Absorbing boundaries increase work hardening.

Transferable boundaries facilitate dislocation movement.

Abstract

The thermodynamic theory of dislocation/grain boundary interaction, including dislocation pile-up against, absorption by, and transfer through the grain boundary, is developed for nonuniform plastic deformations in polycrystals. The case study is carried out on the boundary conditions affecting work hardening of a bicrystal subjected to plane constrained shear for three types of grain boundaries: (i) impermeable hard grain boundary, (ii) grain boundary that allows dislocation transfer without absorption, (iii) grain boundary that absorbs dislocations and allows them to pass later.