Parametric optimization of friction stir welding of AA 6101 T-64 and pure Cu using response surface methodology

The friction stir welding (FSW) process was used to join electrical grade aluminium alloy 6101 T-64 and pure Cu plates and optimized using the Box–Behkan approach of response surface methodology. The tool rotational speed, traverse speed, tool offset, and tool tilt angle were deemed to be relevant parameters since they have a considerable significance on the weld joint properties. By using mathematical models, the relationship between welding parameters and responses (tensile strength σ s and electrical resistivity ρ) is examined. The responses are maximized or minimized in these models. Response plots produced from mathematical models are used to analyze the interaction effects of the FSW parameters on the output responses. Through the use of the analysis of variance (ANOVA) method, the constructed models are validated. The results of the experimental research demonstrated that a wide range of FSW settings can be used to construct sound weld joints without defects. The findings from the tensile strength ANOVA table showed that the tool rotational speed and tool offset were significant parameters, however the traverse speed and tool tilt angle were not significant parameters for tensile strength. From ANOVA table of electrical resistivity all parameters were found significant for electrical resistivity. The experimental results and predicted models showed good agreement. The microhardness study at optimized welding parameters revealed the variations in microhardness distribution in different regions. It is found that the microhardness distribution was higher in the bottom region followed by top region and middle region.