Quasicontinuum Models of Interfacial Structure and Deformation

TL;DR

This paper extends a mixed atomistic-continuum model to study how grain boundaries interact with dislocations and cracks, providing insights into microscopic mechanisms and quantifying critical parameters affecting material deformation.

Contribution

The paper introduces an extended quasicontinuum model to analyze interfacial defect interactions, enabling detailed microscopic understanding and quantitative evaluation of deformation processes.

Findings

Identified mechanisms for defect interactions at grain boundaries.

Quantified stress required to nucleate dislocations.

Determined forces influencing grain boundary migration.

Abstract

Microscopic models of the interaction between grain boundaries (GBs) and both dislocations and cracks are of importance in understanding the role of microstructure in altering the mechanical properties of a material. A recently developed mixed atomistic and continuum method is extended to examine the interaction between GBs, dislocations and cracks. These calculations elucidate plausible microscopic mechanisms for these defect interactions and allow for the quantitative evaluation of critical parameters such as the stress to nucleate a dislocation at a step on a GB and the force needed to induce GB migration.