Plastic deformation and strength of materials in small dimensions

Materials with characteristic crystallite dimensions in the nanometer regime are expected to have interesting and useful mechanical properties (high strength and ductility). However, understanding of these properties has been obscured by variations in the density and possibly the composition of the tested samples. An overview of recent progress in understanding plastic deformation and strength in nanocrystalline metals in bulk and thin film form is presented. Deviations from classical scaling laws are discussed from a mechanistic point of view.