For many years nanocrystalline materials have been produced as curious byproducts of certain manufacturing procedures. The fabrication of thin films by electron beam evaporation and other forms of physical vapor deposition [ 13], the melt spinning of ribbons [4], the electrodeposition of zinc coatings [5], the dehydration and firing of sols (liquid mixtures) to make ceramic fibers and bubbles [6], and the cold drawing and heat treatment of superconductor wires [7] have all yielded solids with sub-100 nm grain sizes. However, not until the recent surge of interest in the properties of such ultrafine-grained materials has a concerted effort been made to design manufacturing procedures specifically with the goal of producing nanocrystalline solids reliably in a variety of bulk sizes and geometries.