Dissimilar Friction Stir Spot Welding of AA2014 and AA7075 Aluminum Alloys

Friction stir spot welding is a novel single-point solid-state joining process for difficult to weld metals by conventional spot welding processes. In the present study, AA2014-T6 (1.7 mm) and AA7075-T6 (2.5 mm) aluminum alloys were friction stir spot welded using optimized process parameters and computer numerical controlled milling machine. The microstructural and mechanical characterizations of developed welds were completed by optical microscopy and tensile tests. The weld joint showed microstructural features typical to friction stir spot welding. The grain size in weld nugget zone, thermo-mechanically affected zone and heat-affected zone was changed significantly as compared to base metals. The maximum shear load on weld joints was found to be 4.15 kN. Fractography was performed using scanning electron microscopy to identify the mode of failure.