A theoretical model was suggested which described the generation of nanoscale voids (nano-voids) at grain boundaries in deformed nanocrystalline and nanocomposite materials. In the framework of the model, nano-voids were generated in the stress fields of the dislocations characterized by large Burgers vectors and formed at grain boundary steps and triple junctions due to intense intergrain sliding. The model accounted  for reported experimental observations of nano-voids at grain boundaries in deformed nanomaterials.

Nanovoid Generation due to Intergrain Sliding in Nanocrystalline Materials. I.A.Ovidko, A.G.Sheinerman: Philosophical Magazine, 2006, 86[23], 3487-502