SYNTHESIS OF NANOSTRUCTURED MATERIALS BY MECHANICAL MILLING - PROBLEMS AND OPPORTUNITIES

Mechanical attrition as a method to produce nanocrystalline (nc) mater ials is reviewed. its advantages include the fact that all classes of materials-including brittle compounds-are amenable to the method; it c an be easily scaled up to tonnage quantities. The phenomenology and su ggested mechanisms for formation of nc microstructures are discussed f or ball milling of single component powders, mechanical alloying of mu lticomponent powders, and mechanical crystallization of amorphous allo ys. The phenomenology is well documented but microscopic mechanisms aw ait better understanding of the nature of deformation processes in nc materials. The problems of contamination and powder consolidation are briefly considered. (C) 1997 Acta Metallurgica Inc.