An analysis on effect of multipass twist extrusion process of AA6061 alloy

Intensive plastic deformation has received the attention of researchers in the recent years. Twist extrusion is one such technique which produces high strain on bulk materials resulting in excellent grain refinement without any change in the overall sample dimensions. The effect of performing three twist extrusion passes on AA6061 aluminum samples at various temperatures were studied numerically and experimentally in this work. The finite element analysis of the von Mises stress and the equivalent strain in the outer cross-sections was carried out on the DEFORM-3D platform successfully. From the simulation results it was observed that the normal plastic strain is more at end of the workpiece compared to the head of the sample. It was also observed that more strain is experienced at the corner region than the centre zone. This variation in strain distribution is decreased by performing more twist extrusion passes. The experimental outcomes such as microstructure evolutions and micro hardness were studied and tensile test results were validated with the simulation results. The billet volume reduction from initial to final stage of deformation was found to be minimum with all twist extrusion passes. (C) 2013 Elsevier Ltd. All rights reserved.