Processing and behavior of nanostructured metallic alloys and composites by cryomilling

Recent interest in nanostructured materials stems, not only from their potential use in a variety of applications, but also from the reported discovery of novel fundamental phenomena. The consolidation of cryomilled powder provides a potential pathway towards large scale manufacturing of nanostructured metallic materials. This approach typically engenders the mechanical attrition of powders in liquid nitrogen, followed by consolidation, using established commercial techniques, such as isostatic pressing and extrusion. In this overview paper, published data are reviewed and discussed with particular emphasis on the following topics: nanostructure evolution mechanisms; primary consolidation and secondary processing methods; thermal stability of cryomilled materials; and mechanical behavior of consolidated materials. Recent mechanical behavior data and the associated mechanisms of cryomilled Al alloys are discussed in an effort to shed light into the fundamental behavior of ultrafine grained and nanostructured materials.