An investigation of microstructural and mechanical properties of friction stir welded Al 6013-T6 alloy

Aluminum alloys are widely used in aircraft structures especially in the fuselage and wing fairings. For the joining of these structures, the traditional technique of riveting is used. However, riveting increases the structural weight of the aircraft and rivet holes cause stress concentration for the fatigue cracks. Intraditional welding techniques, metal is heated up to the melting point for this reason the mechanical behavior of the material deteriorates. In addition to that 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; the weldability by FSW of 6013-T6, an aluminum alloy having an important place in aviation and space industries; the mechanical properties of the material after riveting; and the changes in the internal structure have been examined. Along the course of this study, the raw material, the welded material, and the material which has undergone further heat treatment, have been tested by microhardness test, tensile test, and fatigue test. The microstructure has been examined by the optical microscope and the electron microscope. The particles within metals and the grain structure in the welded material have been analyzed by optical microscope and scanning electron microscope.