Optimization of process parameters of multichannel angular twist extrusion (MATE) to process AA2024 alloy

Abstract

The severe plastic deformation (SPD) processes like Equal channel angular pressing (ECAP) and Twist extrusion (TE) have grabbed the attention of the researcher for producing ultra fine grain (UFG) bulk sample. More number of passes and poor strain homogeneity are the major pitfall of these processes. To overcome this drawbacks a novel single pass process named Multichannel angular twist extrusion (MATE) is devised. In the MATE, the TE, ECAP and direct extrusion channel are integrated; thereby strain is induced in the three regions. The selection of the appropriate process parameters plays a critical role in deciding the effectiveness of the MATE process. So in this work the input parameters like, ram speed, co-efficient of friction and billet temperature were optimized against the Vickers hardness and ultimate tensile strength of the extruded material. Experiments were conducted using Response surface methodology (RSM). Analysis of variance is performed to find the influential input parameters on the mechanical properties. An empirical equation is developed to optimize the process parameter. Based on the results, it is found that co-efficient of friction has the significant effect on the Vickers hardness and ultimate tensile strength. The ram speeds of 4mm/sec, co-efficient of friction of 0.2 and billet temperature of 150°C are identified as optimal input parameters. Considerable increase in the tensile strength and hardness is observed in the MATE proceed sample.