Abstract:Dissimilar AZ31B magnesium alloy and DC56D steel were welded via AA1060 aluminum alloy by magnetic pulse welding. The effects of primary and secondary welding processes on the welded interface were comparatively investigated. Macroscopic morphology, microstructure, and interfacial structure of the joints were analyzed using scanning electron microscope, energy dispersive spectrometer, and X-ray diffractometer (XRD). The results show that magnetic pulse welding of dissimilar Mg/Fe metals is achieved using an Al interlayer, which acts as a bridge for deformation and diffusion. Specifically, the AZ31B/AA1060 interface exhibits a typical wavy morphology, and a transition zone exists at the joint interface, which may result in an extremely complex microstructure. The microstructure of this transition zone differs from that of AZ31B magnesium and 1060 Al alloys, and it is identified as brittle intermetallic compounds (IMCs) Al3Mg2 and All2Mg17. The transition zone is mainly distributed on the Al side, with the maximum thickness of Al-side transition layer reaching approximately 13.53 μm. Incomplete melting layers with varying thicknesses are observed at the primary weld interface, while micron-sized hole defects appear in the transition zone of the secondary weld interface. The AA1060/DC56D interface is mainly straight, with only a small number of discontinuous transition zones distributed intermittently along the interface. These transition zones are characterized by the presence of the brittle IMC FeAl3, with a maximum thickness of about 4 μm.