MECHANICAL-PROPERTIES OF NANOPHASE METALS

Nanophase metals have grain-size dependent mechanical properties that are significantly different than those of their coarse-grained counter parts. Pure metals are much stronger and apparently less ductile than conventional ones; intermetallics are also strengthened, but they tend toward increased ductility at the smallest grain sizes. These properl y changes are primarily related to grain size limitations, but they ar e also affected by the large percentage of atoms in grain boundaries a nd other microstructural features. Strengthening appears to result fro m a limitation of dislocation activity, while increased ductility prob ably relates to grain boundary sliding. A brief overview of our presen t understanding of the mechanical properties of nanophase metals is pr esented.