Multiple extrusion and consolidation of Al-4Mg-1Zr

In the continued quest for metallic alloys with better properties, metallurgists have employed a variety of thermo-mechanical processing routes and non-conventional methods. While steady progress has been made in this area, recent work promises to produce alloys with a step change in properties via severe plastic deformation (SPD) techniques. Several SPD techniques are now being studied such as Equal-Channel Angular Pressing (ECAP), High Pressure Torsion (HPT) and Accumulative Roll Bonding (ARB). In this paper a new SPD technique is applied to a novel experimental alloy, Al-4Mg-1Zr. The alloy has been subjected to six passes of conventional extrusion. The mechanical properties and the microstructure was studied after each pass. Analysis showed that after the each pass the microstructure has been refined, the primary Al3Zr particles were broken down and the hardness increased slightly. However, the yield stress and the ultimate strength increased significantly after the first pass and decreased for the following passes.