Optimising aluminium 2024/7075 friction stir welded joints

Abstract

The present novel work is the investigation of dissimilar AA2024/AA7075 aluminium alloy friction stir spot welded joint. The input welding process parameters were analysed to determine the most influencing process parameter on mechanical and morphological properties of the weld. The welding process and input parameters were optimised by Box–Behnken design and response surface methodology. Among the enhanced mechanical characteristics, tensile shear force was observed to be enhanced to maximum being influenced by the rotational speed of the friction stir tool. Optimised performance characteristics were obtained by using desirability approach, and the resulting optimal input parameters were: Tool plunge depth = 3.3 mm, rotational speed of tool = 2000 rpm and Tool dwell time = 40 s. The optimal tensile shear force and hardness obtained were 4.18 kN and 134 HV, respectively, which were validated by comparing the experimental and predicted output response. The elemental composition and morphology of materials were tcharacterised by X-ray diffraction – scanning electron microscope, while the mechanical properties were analysed by tensile and Vickers hardness testing.