In this study, dissimilar joining of degradable AZ31 magnesium alloy to commercially pure titanium and 316L stainless steel (SS316L) was performed using rotary friction welding (FW). The microstructure, mechanical properties, and corrosion behavior of the joints were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), tensile testing, microhardness measurements, and electrochemical polarization and impedance tests. Both SS316L/Mg and Ti/Mg alloy joints exhibited sound continuity with defect-free weld interfaces. On the Mg side, the microstructure consisted of a dynamically recrystallized (DRX) region, a thermo-mechanically affected zone (TMAZ), and a partial deformation zone (PDZ), whereas no distinct zones were observed on the Ti and SS316L sides. The tensile strengths of the Ti/Mg and SS316L/Mg joints were 174 MPa and 144 MPa, respectively. The increase in hardness of the Mg base metal toward the Ti/Mg interface is attributed to grain refinement induced by elevated temperature and plastic deformation, together with the formation of Ti₃Al intermetallic compounds. In contrast, in the SS316L/Mg joint, Al₃Fe₂ and Al₁₃Fe₄ intermetallic compounds were identified at the interface. Immersion tests further indicated that the corrosion resistance of the SS316L/Mg joint is lower than that of the Ti/Mg joint.
Gogheri et al. (Thu,) studied this question.