Experimental Modeling and Multi-Response Optimization in Friction Stir Welding Process Parameters of AA2024-T3 Using Response Surface Methodology and Desirability Approach

This work deals with the regression models and multi-objective optimization method of the ultimate tensile strength, percentage of elongation, and average arithmetic surface roughness of butt friction stir welded AA2024-T3 aluminum alloy. Machining experiments were carried out according to the face centered central composite design of the response surface methodology. The effect of friction stir welding process parameters such as rotation speed, welding speed, and tool shoulder diameter on responses was investigated. Adequacies of the models are checked by the analysis of variance. The optimization of multiple responses was performed using the desirability analysis to achieve the higher ultimate tensile strength, maximum percentage of elongation, and minimum arithmetic surface roughness. From this investigation, it is found that the joints fabricated with the tool rotational speed of 752 rpm, welding speed of 100 mm/min, and tool shoulder diameter of 12.5 mm yield the maximum ultimate tensile strength and percentage of elongation, and minimum arithmetic surface roughness of 379.69 MPa, 10.22% MPa, and 6.66 HV, respectively. The effects of process parameters on the microhardness of welded zone were studied. The macrostructure, microstructure, and residual stress characterization of joints are examined.