Multi-response optimization of process parameters for weld performances during underwater friction-stir welding of dissimilar aluminum alloys AA6063-T6 and AA5083-H32
Sachin Gadakh, Chitresh Nayak
Abstract
This study investigates the multi-response optimization of process parameters in welding for superior welds performance in welds for AA6063-T6 and AA5083-H32 aluminum alloys. Underwater friction stir welding (UFSW) emerges as a promising technique, offering improved mechanical properties through accelerated cooling rates. The response surface methodology coupled with desirability function analysis was used to optimizing three key process parameters are tool rotational speed, welding speed, and plunge depth. The objective is to simultaneously maximize tensile strength, minimize weld defects, and improve corrosion resistance. Experimental results show that at a weld speed of 17 mm/min and 1400 rpm, the maximum ultimate tensile strength (UTS) of 267 MPa occurs at a 2° tilt angle, while the highest yield strength (YS) of 226.04 MPa is observed at a 1° tilt. Optimal elongation (12.72%), impact energy (18.29 J), and microhardness (102.03 VHN) occur at a 2.5° tilt angle. Analysis of Variance (ANOVA) reveals that spindle speed has a significant impact on UTS, yield stress YS, impact energy, and microhardness, whereas tilt angle predominantly affects elongation. The microhardness profile indicates higher values in stir zone (SZ) and thermo-mechanical affected zone (TMAZ) zones compared to the heat-affected zone (HAZ) and base metal (BM), emphasizing distinct material property variations across weld regions.