Narrow Results

Nowadays, Severe Plastic Deformation (SPD) methods are at the focus of material researchers and among these methods, Twist Extrusion (TE) is one of promising ones to pave the way of commercialization. In this Investigation the magnitude of strain distribution along 4 selected paths of sample after 3 passes of Twist Extrusion were investigated by computer simulation and its influence on aluminum 1100 microstructure by experimental tests. ABAQUS 6.5 software based on FEM was applied for the former and 70 mm length samples with cross-section of 18*28 mm were exploited for the latter. According to the simulation results, corner, middle of small side, middle of long side and center of the cross-section are placed from maximum to minimum magnitude of strain respectively. Theses achievements were verified with metallographic images in aspect of metal flow and grain size as well.

Recently, severe plastic deformation processes have been the essence of metal forming researches to produce ultrafine-grained materials. Twist Extrusion is one of the most unprecedented methods developed in recent years, but has some deficiencies. The main one is the microstructure and mechanical heterogeneity, occurring after twist extrusion. Performing rolling as a conventional forming technique was suggested as a solution in this paper. It not only decreased the grain size, but also reduced the mechanical heterogeneity, and improved the grain size distribution. Employing the twist extrusion process on pure copper samples was carried out using a twisted die with 60° die angle, and the samples were processed through rolling subsequently. The results demonstrated that employing the rolling process enhanced grain size homogeneity and bulk strength.