Dislocation activity and nano-void formation near crack tips in nanocrystalline Ni

Molecular statics is used to study the crack propagation in model nanocrystalline Ni with a mean grain size of 10 nm. It is shown that the crack propagates intergranularly, creating nano-voids ahead of the crack which coalesce gradually. Plasticity in the neighborhood of the crack tip is observed to be mediated by dislocation activity. The sequential emission of partials results in the observation of full dislocations and twinning.