Feasibility Study of Friction Stir Welding of Dissimilar Metals between 6063 Aluminium Alloy and Pure Copper

Abstract

Butt joints of dissimilar metals between 6063 aluminium alloy (Al6063) and commercial pure copper (Cu) were fabricated by friction stir welding (FSW) using the rotational speed of 1100, 1400 and 1800 rpm and welding speed of 20 and 40 mm/min. The effect of rotational and welding speeds in FSW process on surface morphology, microstructure and mechanical properties of dissimilar FSW Al6063–Cu joints was investigated. The experimental results showed that defect–free dissimilar FSW Al6063–Cu joints could be achieved when rotational and welding speeds in FSW process were used as listed follow: 1100 rpm and 20 mm/min, 1400 rpm and 20 mm/min, 1800 rpm and 20 mm/min. Microstructural analysis revealed that a good mixing of Al6063 and Cu metal with lamellar structure was observed. Furthermore, fine Cu metal and Al6063 particles were also found in stir zone (SZ) of the dissimilar FSW Al6063–Cu joints. EDS and XRD results indicated that intermetallic compounds such as AlCu, Al₂Cu and Al₄Cu₉ were formed in SZ of the dissimilar FSW Al6063–Cu joints. High tensile strength of the dissimilar FSW Al6063–Cu joints would significantly result from a large area of SZ in the joints due to using proper welding pitch.