Study of the Mechanical Properties of Lap Joints of Dissimilar Materials using Friction Stir Spot Welding

The lap joining of aluminum alloy AA 6061 to pure copper was fabricated through FSSW (friction stir spot welding). The welding process parameters are actually tool speed, plunge depth, and dwell time. The research work also gives a description of some of the mechanical characteristics from the tensile-shear tests of the AA7020-pure copper joints. The optimization of process parameters achieved quality improvement, while the best process parameters are obtained from the Taguchi L9 design. The present work examines the effect of welding process parameters on shear load and microhardness of the lap joints is a process based on analysis of variance (ANOVA) system procedure. The maximum values of tensile shear load and microhardness are correspondingly equal to 3.77 KN and 87.2 HV, which occurred at a tool speed of 2200 rpm and a plunge depth of 20 mm. It can be noticed that at a tool speed of 2200 rpm, a plunge depth of 0.1 mm, and a dwell time of 20 s. The tensile shear force increases from 2.46 kN (conventional FSSW) to 2.64 kN (Stitch FSSW at 2 mm distance traveled) and 2.68 kN (Stitch FSSW at 4 mm distance traveled). In this present study, the micro and macro structure of the weld specimens is examined.