Microstructural evolution of aluminum/magnesium lap joints welded using MIG process with zinc foil as an interlayer

Abstract Dissimilar material welding between 1 mm-thick magnesium and aluminum alloy plates in lap form was performed using the MIG process with zinc foil as the interlayer material. The zinc foil acted as a barrier layer that restrained reactions between the aluminum and magnesium atoms, and a crack-free lap joint of dissimilar materials was obtained. The interfacial layer between the fusion zone and the unmelted magnesium substrate was mainly composed of Mg–Zn binary intermetallic compounds. The tensile strength of the lap joint was 64 MPa, and a fracture occurred at the interface between the fusion zone and the unmelted magnesium alloy.