Optimization of Wear Parameters on Friction Stir Welded Dissimilar Aluminium Joints

The welds in this study were prepared by adapting a two-pass friction stir welding strategy with a cylindrical pin tool rotated and traversed at 800 RPM and 40 mm/min, respectively. Four pins of parent alloys (AA 6061 and AA 7075), unreinforced, and reinforced weld were subjected to wear characteristic testing. The experimental trials were performed as per Taguchi L 16 orthogonal array using a pin-on-disc machine with varied input parameters like plate/pin type, applied load, sliding velocity, and sliding distance. The output responses namely the wear rate, wear resistance, and coefficient of friction for different pins were analysed using the MINITAB tool, and wear parameters were optimized. The main effects plot presented a reinforced weld pin, an applied load of 10 N, a sliding velocity of 1 m/s, and a sliding distance of 2000 m as optimal conditions for better wear responses. This could be due to the presence of the h-BN phase in dissimilar weld matrix contributing to the emergence of tribo-layer at the interface, dynamic surface interaction, and high dislocation density. Individual response optimization and grey relational analysis are found to be reasonably matched. A confirmation test was performed using the best parameter combination, and the results were compared.