Adding longitudinal alternating intermittent magnetic field, using ER5356 aluminum magnesium welding wire as filler metal, the butt welding of T2 copper plate and 2A16 aluminum alloy plate was carried out, by studying the joint forming, interface structure and mechanical properties under different excitation current IE and excitation frequency f, the optimum technological range of the joint is obtained. The results show that the alternative intermittent magnetic field is introduced to realize the effective connection of the dissimilar materials of aluminum and copper. The copper side welding-brazing joint interface layer is composed of IMC layer and transition layer, among them, IMC layer is AlCu and Al2Cu phase, and the transition layer is α-Al+S(Al2CuMg)/Al2Cu phase. IMC layer and transition layer are crisscross, which has the effect of "mechanical occlusion" and improves the joint strength. With the increase of excitation current, the average thickness of IMC layer first decreases and then increases, and the tensile strength first increases and then decreases; with the increase of excitation frequency, the tensile strength decreases gradually. The best process range is: IE=0.5-0.7 A, f=15-25 Hz, the average thickness of IMC layer d=14.3-15.8 μm, the forming perfor-mance of the joint is good, and the tensile strength is high. When IE=0.6 A, f=15 Hz, the highest tensile strength of the joint is 135.47 MPa. The microhardness of interface layer is 252.8HV, which is significantly higher than that of weld and base metal, this may be due to the brittle and hard intermetallic compounds of AlCu and Al2Cu in IMC layer. © 2021, Materials Review Magazine. All right reserved.
