Optimization of processing variables of friction stir welded dissimilar composite joints of AA6061 and AA7075 using response surface methodology

In the current work, quadratic mathematical models at a 95% confidence level were developed to predict the optimum value of output responses such as the tensile strength, microhardness, and % strain of SiC particles-based friction stir welded composite joints of AA6061 and AA7075. Tool rotating speed, transverse speed, and volume percentage of SiC particles were considered as processing variables to multi-optimize the output responses using the desirability function in the Response surface methodology. ANOVA analysis was carried out to confirm the validity and adequacy of the developed model. The developed models showed that rotating speed is the most influential and transverse speed is the least influential variable. The highest tensile strength of 263 MPa, microhardness of 189 HV, and % strain of 29.4% was found at a rotating speed (RS) of 1200 rpm, transverse speed (TS) of 30 mm/min, and 10% volume percentage of SiC particles. The optimized processing variables, including transverse speed, rotating speed, and volume percentage of SiC particles, were found to be 32 mm/min, 1164 rpm, and 8.7%, respectively. The value of multi-optimized output responses, including tensile strength, % strain, and microhardness, was found to be 252 MPa, 26.7%, and 178 HV, respectively.