Branching mechanism of intergranular crack propagation in three dimensions

TL;DR

This paper explores how intergranular cracks branch in three dimensions, revealing that geometrical randomness of grain boundaries causes partial arresting of crack fronts, leading to branching instability.

Contribution

It introduces a finite element model to analyze slow intergranular crack propagation and discusses the mechanism behind branching instability in disordered media.

Findings

Branching is caused by partial arresting of the crack front due to grain boundary randomness.

Finite element simulations successfully model slow intergranular crack propagation.

A scenario for crack branching instability in disordered materials is proposed.

Abstract

We investigate the process of slow intergranular crack propagation by the finite element method model, and show that branching is induced by partial arresting of crack front owing to the geometrical randomness of grain boundaries. A possible scenario for branching instability of crack propagation in disordered continuum medium is also discussed.