ABSTRACT
The friction stir welding of age-hardened aluminum alloy causes degradation of strength properties in the as-welded condition because of the thermal cycle. Hence, to augment the lost strength of the joints, postweld heat treatment is employed. In this research, the effect of solution treatment and artificial aging on tensile strength was systematically examined. The microstructural features were investigated using a microscope, a scanning electron microscope, and a transmission electron microscope. The relationship between these properties and the grain size, precipitate size, and distribution was studied. Based on the results, it was found that the joint solution treated at 500°C and soaking period of 1 hr followed by aging at 165°C for 12 hrs. yielded a higher load than the counterpart because of the recrystallized grains and density distribution of the second phase particle.
