Friction Stir Lap Welding of Magnesium Alloy and Zinc-Coated Steel

Abstract

AZ31 Mg alloy and zinc-coated steel were lap welded using friction stir welding technology. The microstructures and mechanical properties of the joints were examined. The lap shear tensile test results showed that the welding speed had a significant effect on the failure loads of the joints at the rotation speed of 1500 rpm. The maximum failure loads of 3.4 kN, 65% of that of the zinc-coated steel base material, could be obtained when the welding speed was 150 mm/min. Microstructure analysis showed that the intervention of zinc coat promoted the formation of Mg-Zn low-melting-point eutectic structure at the interface. The joining mechanism and the role of Zn coat on friction stir lap welding of Mg alloy and zinc-coated steel were put forward.