Properties and Nanostructures of Materials Processed by Spd Techniques

Metallic materials usually exhibit higher strength but lower ductility after being plastically deformed by conventional techniques such as rolling, drawing and extrusion. In contrast, nanostructured metals and alloys processed by severe plastic deformation (SPD) have demonstrated both high strength and high ductility. This extraordinary mechanical behavior is attributed to the unique nanostructures generated by SPD processing. It demonstrates the possibility of tailoring the microstructures of metals and alloys by SPD to obtain superior mechanical properties. The SPD-generated nanostructures have many features related to deformation, including high dislocation densities, and highand low-angle grain boundaries in equilibrium or non-equilibrium states. This paper reviews the mechanical properties and the defect structures of SPD-processed nanostructured materials.