Investigation of tube joining between AA1050 and Inconel 625 using the electromagnetic pulse process: Experimental and numerical insights

The integration of Inconel 625's exceptional mechanical properties, such as high strength, corrosion resistance, and thermal stability, with AA1050's lightweight characteristics and superior thermal conductivity is frequently employed in tube lap joints in high-performance applications across the aerospace, chemical processing, marine, and cryogenics industries. Magnetic Pulse Crimping (MPC) leverages a high-intensity pulsed magnetic field to induce a Lorentz force on a conductive flyer, which impacts a stationary target workpiece, resulting in a mechanically interlocked joint. The present study aims to optimize the joint strength of AA1050/Inconel 625 tube-to-tube connections under varying discharge energies, utilizing MPC with a robust Archimedean spiral primary coil and an integrated field shaper. The failure modes observed during pullout testing include slip failure, base metal failure, joint failure, and flyer tube fracture, with the discharge energy being a significant influencing factor. The distribution of joint thickness and the leak-tightness of the samples were systematically evaluated across all discharge energy levels. In addition, a detailed microstructural analysis of the joint interface was performed using Scanning Electron Microscopy (SEM) to elucidate the diffusion phenomena and material interaction during the impact joining process. A numerical simulation was conducted using LS-DYNA coupled with the electromagnetic (EM) module to corroborate against experimental data. This research presents a novel high-speed cold joining approach for AA1050/Inconel 625, demonstrating the potential of MPC for advanced material joining applications.