Friction Stir Welding of Al ۲۰۲۴ with Al ۷۰۷۵ Alloys and evaluate its structural and mechanical properties

The overarching goal of this research was to use the FSW method to join the Al ۲۰۲۴ and Al ۷۰۷۵ alloys, examine the structural and mechanical properties of the joint, and eventually find the optimum welding parameters. The welding operation was carried out using a milling machine and a device with cylindrical pins. The transverse cross-section of the weld was used for optical as well as electron microscopy observations. The evaluation of mechanical properties at room temperature i.e., tensile strength and hardness were done. The size of the grains measured using an optical microscope varied between approximately ۲.۶ and ۱۱ µm. The results of the welding process revealed that the specimen with a traverse speed of ۳۰ mm/min, a rotation speed of ۶۰۰ rpm, and the highest ultimate tensile strength (۱۹۵ MPa), and the specimen with a traverse speed of ۷۰ mm/min, a rotation speed of ۱۲۰۰ rpm, and an ultimate tensile strength of ۱۹۳ MPa were selected as the optimum specimens due to their off-fusion-zone failure, their high strength in the tensile strength test, and their adequate input heat. Moreover, in the specimen with the traverse speed of ۱۰۰ mm/min and the rotation speed of ۶۰۰ rpm, the highest percentage of elongation (۳.۸۰%) was observed in the tensile strength test. The results from the tensile test indicated that with a decrease in the traverse speed, the tensile strength of the specimens increased, the elongation percent decreased, and the stirring improved.