Magnetic pulse welding of high-strength aluminum alloy with enhanced Lorentz force via novel hollow field shaper

Magnetic pulse welding (MPW) has been widely applied to join metallic tubes in the automotive and aerospace fields. However, low energy utilization of the device limits the Lorentz force and the application to high-strength alloys. A novel hollow field shaper structure is proposed to expand the range of potentially applicable materials. Topology optimization was employed to trade off the efficiency and the strength of the device. The welding of 6061-T6 aluminum-alloy tube and 1020 steel tube was realized. The joint strength has increased threefold. The results showed that under the enhanced Lorentz force , the element was diffused into each other. The numerical study found that the Lorentz force from the novel design was enhanced by 56 %. The radial deformation in the free deformation experiment increased by 243.3 %, validating the improvement of the force. By creating an analytical model, it was analyzed that the increase in force was due to the decrease in current division on the sloping surface of the hollow field shaper. Besides, the efficiency increased by 66.7 % implying lower energy costs. Thus, the proposed structure was validated to expand the materials range of MPW. • MPW of joining carbide and mild steel tubes with enhanced Lorentz force via novel field shaper is proposed. • The induced current distribution and magnetic field enhancement mechanisms of the hollow structure are revealed. • A novel structure balancing energy efficiency and device strength is achieved through continuum topology optimization.