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

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.;hear 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 3.4kN, 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. [doi: 10.2320/matertrans.M2009022]