Study on interfacial morphologies of AA1060 and SS321 magnetic pulse welded joints

Abstract

In this study, the application of magnetic pulse welding was employed for the production of tubular joints using 1060 aluminium and 321 stainless steel. Two crucial process parameters, the charging voltage, and the gap between the outer and inner tubes, were subjected to mechanical property tests and morphology analysis. The joints that exhibited favourable mechanical properties were obtained with a gap size of 1.25 mm and a charging voltage exceeding 3.5 kV. The presence of intermetallic compounds at the joint interface indicates the occurrence of fusion in the transition zone. The quantity of molten metal increased with an increase in the charging voltage. The aluminium content in the intermetallic compounds within the transition zone decreased as one moved from the 1060 aluminium side towards the 321 stainless steel side. The gap distance plays an important role in determining the efficiency of energy transformation at the joint interface during magnetic pulse welding (MPW). A smaller gap distance resulted in a substantial amount of energy being transformed into plastic deformation in the transition zone. Conversely, a greater gap distance led to a significant amount of energy from the electrical charging voltage being converted into thermal energy. The MPW joint consisted of bonding, mechanical interlock, and non-bonding regions. The mechanical properties of the joint were influenced by the composition of the intermetallic compound. Taking into account the impact of morphologies and elastic modulus of the transition zone, an increase in the melting of stainless steel during the welding process was found to be advantageous for the MPW of 1060 aluminium to 321 stainless steel.