Optimization of process parameters in friction stir welding of dissimilar aluminum alloys (AA6061-T6 and AA5052-H32)

Friction stir welding (FSW) is a solid-state welding method for the welding of aluminum alloys and has been used in aerospace, railway, automotive, and marine applications. Solid-state welding processes solve several problems that occur during fusion welding of Al-alloys like HAZ liquation cracking, porosity, and segregation. Aluminum alloys of two different series AA5052 and AA6061 thickness of 6 mm are FS welded using process parameters like tool rotational speed (900, 1100, 1400) rpm, transverse speed (40, 50, 60) mm/min, and pin profiles (cylindrical, conical, and square). This article aims to optimize the mechanical and metallurgical properties of the above dissimilar combination to evaluate the performance and characteristics of the welded joints. The combined Taguchi and Grey relation analysis experimental method was chosen to construct the number of welding experiments. The plates are successfully welded, and the welded plates are tested at room temperature to examine their tensile strength and hardness. The findings indicate that the maximum tensile strength of 183.04 MPa, which is 79.58% with AA5052-H32 and 59.05% with AA6061-T6 individually of the base material strength and the square pin profile, the rotational speed of 1400 rpm, and the transverse speed of 40 mm/min are the optimum parameters for joining these dissimilar joints. Tool pin profile has the most prominent FSW process parameters, with a 54.15% contribution.