Grain size effect on crack blunting in nanocrystalline materials

The effect of grain size on the blunting of cracks in nanocrystalline materials is described theoretically. Within our description, lattice dislocations emitted from cracks are stopped at grain boundaries. The stress fields of these dislocations suppress further dislocation emission from cracks in nanomaterials, and the suppression depends on grain size. The dependence of the number of dislocations emitted by a crack on grain size in nanocrystalline Ni is calculated, and characterizes the grain size effect on crack blunting.