Nanostructured materials -mind over matter-

Considerable interest is being exhibited in the novel and enhanced properties of nanostructured materials. These materials, with their constituent phase or grain structures modulated on a length scale less than 100 nm, are now artificially synthesized by a wide variety of physical, chemical, and mechanical methods. Nanostructured materials with modulation dimensionalities of zero (clusters), one (multilayers), two (ultrafine-grained overlayers), and three (nanophase materials) are considered. The basic principles involved in the synthesis of these new materials are discussed in terms of the special properties sought using selected examples from particular synthesis and processing methodologies. Some examples of the property changes that can result from one of these methods, cluster assembly of nanophase materials, are presented.