Microstructure and mechanical performance of dissimilar metal joints of aluminium alloy and stainless steel by cutting-assisted welding-brazing

The 5052 aluminium alloy and 304 stainless steel were successfully joined by cutting-assisted welding-brazing (CAWB) method without using flux. Dual-scale interfacial structures were achieved by designing the geometry of cutting tool. Results indicated that the macroscale self-locking interface was produced when the taper step-shape cutting tool was adopted. Especially when the cutting tool step was increased to 6 steps, the microscale interface took on a micrometre-sized self-locking morphology and a layer of wavy intermetallic compound (IMC) with an average thickness of 3.3 μm was formed at the interface. The τ₄ IMC particles and the FeAl₆ phases on a small scale were dispersed homogeneously in the welded seam. The maximum tensile strength of the joints reached 152.3 MPa, 75% that of the 5052 aluminium base metal. The robust Al/steel dissimilar joints were attributed to the particle-reinforced weld metal and the macro- and microscale dual self-locking structure at the interface.