Abstract
In this work, the effects of rotational and traverse speeds on the 1.5 mm butt joint performance of friction stir welded 2024-T4 aluminum alloy sheets have been investigated. Five rotational speeds ranging from 560 to 1800 rpm and five traverse speeds ranging from 11 to 45 mm/min have been employed. The characterization of microstructure and the mechanical properties (tensile, microhardness, and bending) of the welded sheets have been studied. The results reveal that by varying the welding parameters, almost sound joints and high performance welded joints can be successfully produced at the rotational speeds of 900 rpm and 700 rpm and the traverse speed of 35 mm/min. The maximum welding performance of joints is found to be 86.3% with 900 rpm rotational speed and 35 mm/min traverse speed. The microhardness values along the cross-section of the joints show a dramatic drop in the stir zone where the lowest value reached is about 63% of the base metal due to the softening of the welded zone caused by the heat input during joining.