Effect of welding parameters and aging process on the mechanical properties of friction stir-welded 6063-T4 Al alloy

Abstract

6063-T4 Al alloy was friction stir welded at various tool rotations (800, 1120, and 1600 rpm) and welding speeds (200 and 315 mm/min) using a specially manufactured tool with a height-adjustable and right-hand-threaded pin. The postweld aging process (at 185 A degrees C for 7 h) was applied to a group of the welded plates. In this study, the effects of the welding parameters and the postweld aging treatment on the microstructural and mechanical properties of 6063-T4 Al alloy were studied. The maximum weld temperatures during the welding process were recorded, and the fracture surfaces of tensile specimens were examined using a scanning electron microscope. The homogeneous hardness profiles were obtained for all the weldings with no trace of softening regions. It was observed that the ultimate tensile strengths (UTS) increased slightly (on average by approx. 8%) and the percent elongations decreased (on average by approx. 33%) by the postweld aging treatment. The maximum bending forces (F (max)) of all the welds were less than that of the base metal. It was observed that the F (max) values increased after the postweld aging process at the welding speed of 315 mm/min and decreased at the welding speed of 200 mm/min.