Microstructure and mechanical property of welding-brazing joint between aluminum and steel by micro-beam plasma welding

Butt welding-brazing joint between 6010 aluminum alloy and galvanized steel sheets was obtained by micro-beam plasma welding method. A sound weld joint could be obtained in the suitable welding parameter. The analysis was carried out for the weld joint morphology, microstructure and mechanical property using metallographic microscope, scanning electron microscope, energy-dispersive spectrometer and universal tensile testing machine. The results show that a good spreading width is got in back and front sides of weld joint, there are no obvious crack, pore, slag in the joint, and the joint shows a typical welding-brazing characteristic. The serrated intermetallic compound Fe₂Al₅ is formed at the interface. The joint strength is determined by the thickness of intermetallic compound layer and the spreading width. When the welding current is 38.5 A, the tensile strength of weld joint is 193 MPa, which can reach 79.8% of aluminum base material. The fracture form of joint is ductile-brittle fracture.