A study on mechanical properties in friction stir lap welding of AA 6061-T6 and AISI 304

This article focuses on the study of mechanical properties of lap joints between AA 6061-T6 and AISI 304 stainless steel having a thickness of 1mm each using friction stir welding. The effect of process parameters such as welding traverse speed and plunge depth (pin penetration) on the ultimate tensile strength, microhardness, and bonding mechanism have been studied. Welding traverse speed and plunge depth appear to be very influential parameters on the mechanical properties. Microhardness profile reveals that the maximum hardness occurs at the interface zone, which indicates the brittle nature of the intermetallic compound. AlFe, Al13Fe4 and AlCrFe2 were detected at the interface zone by using XRD tests. SEM study shows that the fracture in the heat affected zone is quasi-cleavage in nature.