Dissimilar butt friction stir welding of Al 5083-H321 and 316L stainless steel alloys

The effect of rotational and traverse speeds during dissimilar butt friction stir welding of Al 5083-H321 and 316L stainless steel plates was studied. The macrostructure and microstructure of the joints were examined using optical microscope and scanning electron microscope equipped with energy-dispersive X-ray analysis. The strength of the joints was measured using tensile test. The results showed that with increasing the rotational speed, the tensile strength of the joints increased up to a maximum value and then decreased. In addition, decreasing the traverse speed resulted in higher tensile strength. The 238-MPa maximum value of the tensile strength was achieved at rotational speed of 280 rpm and traverse speed of 160 mm/min. The formation of surface and cross section defects at lower rotational speeds and higher traverse speeds and existence of cracks and microcracks at higher rotational speeds were responsible for the lower tensile strengths of the corresponding joints. In addition, the FeAl3 intermetallic compound was detected in the interface of the steel particles and Al.