Effect of Strain Per Pass on Microstructure and Mechanical Properties of Multi-Axially Forged Cast AA5083 Alloy at Room Temperature

Abstract

This paper investigates the effect of strain per pass over a cycle on, multi-axially forged cast AA5083 alloy at room temperature. To begin with, Multi-Axial Forging (MAF) with two different strains per pass was imposed on the alloy without changing the die geometry. Samples were deformed to cumulative strains of Σɛ = 2.46 (2 Cycles) and Σɛ = 2.79 (3 Cycles), with two different strains per pass ε = 0.41 and ε = 0.31 respectively. Microstructural analysis was carried out by using OM, XRD, and SEM with EDS. Structural changes were characterized, and it was revealed that grain fragmentation was caused by the frequent development of deformation and micro shear bands, which was followed by the evolution of new fine grains in the original grain structure. Mechanical properties were evaluated by tensile, and hardness tests. MAF of ɛ = 0.41 per pass results in high tensile strength and hardness, 428 MPa and 147 Hv; respectively at a cumulative strain of Σɛ =2.46. Processing with strain ɛ = 0.31 per pass produced strength of 380 MPa and hardness of 131 HV after cycle III with a cumulative strain of 2.79. MAF of strain ɛ = 0.41 per pass with cumulative strain of 2.46 resulted in a higher grain refinement structure with increased strength compared to a strain of 0.31 per pass with a cumulative strain of 2.79. Therefore, with the imposition of the high strain per pass produced more grain refinement and consequently higher strength.