Large Local Deflections of a Dynamic Crack Front Induced by Intrinsic Dislocations in Brittle Single Crystals

We show that intrinsic dislocations in brittle single crystals can be a source of strong local perturbations along the crack path. A theoretical model was developed which predicts substantial crack front deflections. Investigating the crack surfaces in Si crystals with induced dislocation density of [Formula presented] revealed a significant amount of crack front perturbations in the form of V-shaped grooves, which were completely missing in dislocation-free Si specimens. The measured depths of the perturbations were in the range of 2–20 nm and in excellent agreement with the theoretical model.