New Developments in the Processing of Bulk Nanoscale Metals Using High-Pressure Torsion

High-pressure torsion is a processing technique involving the application of a high pressure with concurrent torsional straining. Excellent grain refinement may be achieved using this process with the average grain size often reduced to the nanoscale range. Although this processing is expected to lead to significant microstructural inhomogeneity, experiments consistently demonstrate a gradual evolution towards a homogeneous structure. Recent results have also revealed unusual flow patterns in HPT processing including grain agglomeration in a two-phase alloy and the development of double-swirls and vortices in a stainless steel. ?? 2010 American Scientific Publishers.