Effects of different interlayers on the microstructure and properties of Mg/Cu dissimilar alloy welded joints

AZ31B Mg alloy and Cu (T2) were combined with different interlayers and laser pulse-welded in the form of lap joints. The microstructure and properties of Mg/Cu dissimilar alloy welded joints of different interlayer materials were studied. The results indicated that the morphology of the welded joint of different interlayer materials were unique. There were cracks in the welded joints of Ti foil and Sn foil. The best welding profile was observed from the Zn foil middle layer, and Cu2Ti and MgZn were formed in Ti and Zn foil welded joints, respectively. The msc marc software was used to simulate the welding temperature and stress of different welded joints. The average thermal stress on the Cu surface was significantly reduced by the different interlayers. The corrosion potential (Ecorr) of the Ti foil welded joint was −0.9111 V, and the corrosion current densities (Icorr) with the Ti foil, Zn foil, and noninterlayer were 32.612, 332.551, and 538.473 μA/cm2, respectively. The corrosion resistance of the welding joints by the Ti foil was the best. The most favorable interlayer was Zn foil, and the shear strength was 48.15 MPa, which was 161% higher than that of the without interlayer welded Mg/Cu joint.