The role of recalcitrant grain boundaries in cleavage cracking in polycrystals

Recalcitrant grain boundaries offer an important resistance to cleavage crack advance through crack trapping. In this article, this effect is studied based on an energy analysis. It is found that the critical energy release rate is dominated by a single parameter, Q, that collects together factors such as work of separation, grain size, and crack length. For short cracks, the crack trapping effect leads to an increase in fracture resistance by 20-30%. For long cracks, the crack trapping effect is negligible.