Modeling and optimization of process parameters for friction stir welding of dissimilar aerospace alloys AA2014 and AA7075

Aluminum alloys possess a high strength-to-weight ratio and good corrosion resistance making them suitable for various structural parts and components used in the aerospace industry. However, the principal barrier restricting their use is their weldability. This experimental study addresses the issues in joining of dissimilar aerospace aluminum alloys. In this work, friction stir welding (FSW) of dissimilar high strength alloys AA2014 and AA7075 has been carried out and the effect of welding parameters has been studied to obtain defect-free high strength welds. Detailed statistical analysis was performed and suitable regression models were developed for prediction and optimization. Multi-objective optimization has been carried out by employing the desirability function to determine the optimal condition for defect-free welds with adequate mechanical properties. Microstructure and fracture surface of the optimum weld was also studied and compared with the lowest and highest heat input welded joints.