A Survey on Technological Developments for Fabricating Nanostructured Metals and Alloys

Since the early studies of Hall and Petch, it is a well known fact that fine grain sized materials have better mechanical properties, namely strength, hardness and toughness. However, conventional processing techniques have never been able to produce ultrafine grained metals and alloys, i.e., these methods can not achieve fine grain size beyond some limits around a few micrometers. More recently, the development of new processes comprising severe plastic deformation has demonstrated some capability of producing ultrafine grained, or even nanostructured, materials with better mechanical properties, opening a wide landscape of opportunities for applications in many industrial fields. In this work, new technological developments on the processing of nanostructured metallic materials by severe plastic deformation methods are described, focusing on an analysis of patents registered in the last years on this subject, complemented by available information collected on articles published about this theme.