Relationship between micro-structure and mechanical properties of dissimilar aluminum alloy plates by friction stir welding

Friction stir welding can be applied to weld dissimilar aluminum alloys which have different chemical and mechanical properties without causing any weld defects under a wide range of welding conditions. In this study, AA2024-T3 and AA6063-T6 aluminum alloys were selected and successfully welded in butt position together using by friction stir welding. The welding trials were conducted using different rotational speed and traverse speed conditions also investigating their effect on mechanical and micro-structural behavior of friction stir welding joints. The micro-structural evolution of the material was analyzed by optical observations and scanning electron microscopy inspections of the weld cross-sections. Tension and fatigue studies were also employed to the study. On the other hand, the fracture characterizations of samples were examined by scanning electron microscopy. Fatigue tests were performed by using a resonant electro-mechanical fatigue testing machine by axial bending fatigue test procedure. The fatigue strength has been analyzed drawing S-N curves. Experimental results indicate that micro-structural and mechanical properties are significantly affected by changing welding parameters within the chosen range of welding conditions