A new severe plastic deformation method by repetitive extrusion and upsetting

A novel ultra-high straining process, based on the combination of conventional direct extrusion followed by the upsetting of a cylindrical rod in several cycles of severe plastic deformation (SPD), is presented. This procedure, called repetitive extrusion and upsetting (REU), begins with the extrusion in order to elongate the grains. After extrusion, the specimen is upset until the initial diameter is reached again, so the direct extrusion process can be repeated. During extrusion and upsetting processes, the grains are fragmented along shearing planes. Four cycles of successive REU have been applied to commercial purity aluminum. The effective strain and the potential for grain refinement were evaluated. Preliminary microstructure investigations and mechanical properties evaluation of the processed specimen were carried out.