Aluminium alloys are widely used on aircraft structures especially on the fuselage and wing fairings. During the joining of these structures, the traditional technique riveting is used. But riveting increases the structural weight of the aircraft and rivet holes form stress concentration for the fatigue cracks. An alternative joining technique is welding. In traditional
welding techniques metal is heated till the melting point for this reason the mechanical behavior of the material deteriorates. And also the weldability of high strength materials is low. In recent years Friction Stir Welding (FSW) has been used as an alternative joining technique. In this study T6 heat treatment is applied to Aluminium 6013 sheet and this sheet joined by using FSW technique. Tensile specimens were machined from the welded plate in the dimension of A0 = 12.5 mm, l0 = 200 mm and tensile tests were performed. Vickers microhardness values were taken at 1 mm increments from base metal to base metal across the weld, on the weld cross-sections. The intermetallic particles and the grain structure of the welded sheet were examined via optical and scanning electron microscopy.