EFFECT OF SOLUTIONIZING TEMPERATURE AND COLD ROLLING ON THE MECHANICAL PROPERTIES AND MICROSTRUCTURE OF AA6061 ALUMINIUM ALLOY

ABSTRACT
AA6061 wrought Al-alloys of 6xxx series were heat treated chiefly involving solutionizing heat treatment, age hardening and cold deformation rolling. The solution heat treatments were conducted at various temperatures, the age hardening was carried out at a constant temperature for all specimen and the cold deformation was varied at three different levels of percentage deformation. Their effects were examined in terms of microstructure using optical analysis and mechanical properties by tensile tests, hardness and impact measurements. The solutionizing treatment done at various temperature namely (520◦C, 530◦C and 540◦C) for solution heat treatment and aging treatment at a constant temperature of 180◦C. Deformation ratio of about (10%, 20% and 30%.) was done on the samples after aging. The changes in hardness and microstructure during heat treatments were determined by traditional material characterization methods. Nearly 180.5 HB hardness was obtained with solutionizing at 530◦C, aging at 180 ◦C for 4 h and 30% percentage deformation, which was the optimum treatment for obtaining peak hardness. When shaping (deformation) was concerned, a little higher strength and hardness achieved as compared to the nondeformed alloy due to lower strains.