Dislocation impediment by the grain boundaries in polycrystals

TL;DR

This paper develops a thermodynamic dislocation theory that models how grain boundaries impede dislocation movement in polycrystals, successfully simulating stress-strain behavior and slip distributions during load reversal.

Contribution

It introduces a physics-based model incorporating grain boundary effects to accurately simulate polycrystal deformation under shear tests.

Findings

Simulates stress-strain curves consistent with experimental data.

Provides detailed slip distribution evolution during load reversal.

Explains extended transition stages in load reversal.

Abstract

Thermodynamic dislocation theory incorporating dislocation impediment by the grain boundaries is developed to analyze the shear test of polycrystals. With a small set of physics based material parameters, we are able to simulate the stress-strain curves for the load and its reversal, which are consistent with the experimental curves of Thuillier and Manach [2009]. Representative distributions of plastic slip under load and its reversal are presented, and their evolution explains the extended length of the transition stage during load reversal.