Synergistic Manufacturing of Efficiency, Formation Quality, and Strength for Al/Mg Alloy Joints via Submerged Friction Stir Welding

The dissimilar welding of Al/Mg alloys is a challenging task due to conflicting requirements among efficiency, quality, and load‐bearing capacity. ZK60 Mg/6013‐T6 Al alloys are joined by submerged friction stir welding (SFSW) to meet three requirements. The experiment achieves the coordination between the formation and strength of the materials at a high welding speed of 200 mm min −1 . The appropriate rotational velocity (650 rpm) is adopted to ensure the flow of the materials to promote excellent formation of flash‐free and defect‐free, and to avoid thick intermetallic compound (IMC) layer due to excessive heat input. Metallurgical bonding and mechanical connection are observed on the cross section of the joint at 650 rpm, 200 mm min −1 , enhancing formation and strength. The growth of intermetallic compounds (IMCs) is inhibited with the IMC layer thickness only 1.59 μm, only one‐tenth of the conventional FSW joint, which greatly improves the mechanical properties. Dimples are found at the fracture of the SFSW joint, and the fracture mode is a mixed ductile‐brittle fracture, confirming that inhibiting the growth of IMCs is important for enhancing the mechanical properties. The joint is obtained at 200 mm min −1 with excellent formation, and the ultimate tensile strength of 156 ± 10 MPa.