Optimization of Process Parameters for Friction Stir Welding of Dissimilar Aluminum Alloys Using Response Surface Methodology
Authors: A. Kumar, R. Singh, S. Sharma
Friction stir welding (FSW) is a solid-state joining process widely used for dissimilar aluminum alloys in aerospace and automotive applications. This study investigates the effect of process parametersโtool rotational speed, welding speed, and tool tilt angleโon the mechanical properties of friction stir welded joints of AA6061-T6 and AA7075-T6 alloys. Response surface methodology (RSM) based on central composite design was employed to develop empirical models for tensile strength, hardness, and elongation. Analysis of variance (ANOVA) revealed that rotational speed and welding speed significantly affect the joint properties, while tool tilt angle has a lesser influence. The optimal parameters were found to be a rotational speed of 1200 rpm, welding speed of 60 mm/min, and tilt angle of 2ยฐ, yielding a maximum tensile strength of 245 MPa, which is 82% of the base metal strength. Microstructural analysis showed fine equiaxed grains in the nugget zone, contributing to enhanced mechanical properties. The developed models can be used to predict and optimize FSW parameters for similar dissimilar alloy combinations.
