Enhancement of joint strength of dissimilar aluminum/polymer hybrid joints by friction stir spot welding by surface textures

The joining of different materials, particularly metals and polymers, is exceptionally challenging due to the necessity of producing lightweight hybrid structures in the automotive, aeronautics, and shipbuilding industries. In this research, an attempt was made to fabricate hybrid joints between aluminum alloy 5052-H32 and polycarbonate. The weld joint was made using friction stir spot welding. Response surface methodology was used to optimize the working process parameters. In addition, laser presurface treatment techniques were used to compare the joint’s performance. The mechanical and metallurgical findings demonstrate that these welds were effectively bonded together. Chemical adhesion was found to be the bonding mechanism between these dissimilar materials. The maximum tensile shear value obtained was 19.02 MPa at a tool rotational speed (TRS) of 1381 rpm, dwell time (DT) of 10 sec, and plunge depth (PD) of 0.9 mm in friction stir spot welding. Interestingly, the maximum joint strength of 23.37 MPa was obtained with the influence of laser-based presurface treatment at the same optimized welding parameters. This technology offers a feasible alternative to mechanical fastening and adhesive bonding for structural applications.