Nano-and Micro-Mechanical Properties of Ultrafine-Grained Materials Processed by Severe Plastic Deformation Techniques

The processing of bulk metals through the application of severe plastic deformation (SPD) provides the potential for achieving exceptional grain refinement leading to ultrafine-grained (UFG) materials. These materials generally exhibit high strength but very limited ductility at room temperature. The recent development in the nanoindentation technique provides significant feasibility in evaluating the micro-mechanical behavior of UFG materials. Accordingly, this review examines the available experimental results showing the enhancement in strength and ductility through nanoindentation analysis in various materials after different SPD techniques. A comprehensive tabulation is also presented listing the available data for the strain rate sensitivity, m, in a variety of UFG metals processed by SPD.