Experimental studies and optimization of process variables in multi-angular twist extrusion (MATE) of Cu-Cr-Zr alloy

Abstract

Researchers have recently interested in devising integrated severe plastic deformation (SPD) techniques that can create ultra-fine grained (UFG) metal in one pass. This paper proposes a novel integrated severe plastic technique called multi-angular twist channel extrusion (MATE). This technique was created the aim of retaining strain uniformity while applying a significant strain in a single pass. The input parameters such as annealing temperature, type of lubricant and ram speed, were optimized in this study in relation to the Vickers hardness, hardness inhomogeneity and ultimate tensile strength of the extruded material. Experiments were carried out based on full factorial design, and the TOPSIS approach was used to find the best combination of input parameters. The analysis of variance is used to determine the amount of contribution of input parameters on the mechanical properties. Finite element analysis was performed with the identified optimum parameter of annealing temperature = 550 °C, type of lubricant = MoS2 and ram speed = 3 mm/sec. The average effective strain of 2.72 is obtained by in the MATE process. Experimental studies revealed that the strength and hardness of copper alloy was increased by 69.8 % and 80.5 % respectively. Scanning electron microscope image revealed the grain refinement by MATE process in the copper alloy.