Optimization of ultrasonic assisted friction stir welding (UAFSW) of electrical grade AA 6101T-64 and Cu

Ultrasonic assisted friction stir welding (UAFSW) of electrical grade aluminum alloy 6101 (T-64) and pure Cu plates was performed with Box–Behnken design matrix and optimized by response surface methodology. Tool rotational speed, machine table traverse speed, tool pin offset, and tool tilt angle are taken into account as experimental parameters since they play a key role in the formation of sound weld joints. The correlation between UAFSW input process parameters and output response variables (ultimate tensile strength σ_s and electrical resistivity ρ) is studied in this research work by developing the mathematical models. In order to maximize or minimize the responses, the process is optimized. The interface effects of the UAFSW input process parameters on the output responses variables are interpreted using the response plots generated using the mathematical models. Analysis of variance (ANOVA) is used to verify the established models. As per the ANOVA table, the tool rotational speed and tool pin offset were the significant input process parameters for σ_s of the weld joint. On the other hand, it was observed that all the parameters were significant for ρ. Good agreement was seen between the experiment results and the predicted models of the research. The microhardness evaluation showed the variations in the distribution of microhardness in top zone, middle zone, and bottom zone of the weld joint cross section. Peak microhardness distribution was observed in the top zone of the weld joint cross section followed by middle zone and bottom zone.