New Methods for Severe Plastic Deformation Processing

Several new concepts for possible methods of severe plastic deformation (SPD) of bulk quantities of materials are presented. The first of these are variations of equal channel angular extrusion (ECAE) in which the conventional fixed die is replaced by rotating tools, for the inner die corner, the outer die corner, or both corners. Other methods share some characteristics of ECAE in that they use shearing strains to deform the material; these are reversed shear spinning and transverse rolling. Deformation sequences for a cylindrical or annular workpiece that deform the workpiece while eventually restoring the initial workpiece geometry can be performed by numerous processes. These techniques can be used to accumulate high strains by repeated deformation cycles. These methods offer possible alternatives to ECAE and high-pressure torsion, with potential benefits that include different and larger workpiece geometries, simplified tooling design, lower tooling loads, ease of lubrication, automated or reduced part handling, and, in some cases, potentially continuous operation. It is hoped that these suggestions will prompt new examination of alternative methods for SPD. This article was presented at Materials Science & Technology 2006, Innovations in Metal Forming symposium held in Cincinnati, OH, October 15-19, 2006.