Multi-response optimization of friction stir welding process of dissimilar AA3003-H12 and C12200-H01 alloys using full factorial method

In current research work, an attempt has been made to join dissimilar metals by employing friction stir welding (FSW), i.e., AA3003-H12 (aluminium alloy) and C12200-H01 (copper alloy). The experiments are designed as per full factorial design at different process parameters, namely tool pin profiles, rotational speed, welding speed, and shoulder diameter while the ultimate tensile strength (UTS), yield strength (YS), and percentage elongation (% E) are considered as a performance parameter. Moreover, a statistical tool, i.e., analysis of variance (ANOVA) is also utilized to check the adequacy of the results. It is observed that the higher UTS, % E and YS are obtained by employing a taper pin profile tool at a rotational speed of 1800 rpm, a welding speed of 16 mm/min, and a shoulder diameter of 22.5 mm. The ANOVA results showed that the rotational speed is the most significant factor for current research work. In addition, a scanning electron microscope is utilized for microstructural analysis of welded joints. It is witnessed that the minimum grain size, i.e., 4 microns, is obtained for highest strength specimen and the maximum grain size is obtained for the lowest strength specimen i.e., 31 microns. Besides this, the swirling of cu particle is also observed from advancing side (AS) to the retreating side (RS). Moreover, energy-dispersive X-ray spectroscopy (EDS) indicates the formation of intermetallic compounds i.e. Al₂Cu, Al₉Cu₄ at nugget zone (NZ). The hardness is found to be higher at NZ due to the presence of Al-Cu intermetallic.