The morphology and evolution in Al-Cu and Al-Fe magnetic pulse weld interfaces characterized through phase-contrast micro-tomography

Abstract

Magnetic Pulse Welding (MPW) facilitates the permanent joining of dissimilar metallic materials through the sudden impact generated by a magnetic pulsed field. The process can introduce distinct morphological features at the interface of bi-material joints, which subsequently affect the joint’s quality and durability. This article delves into the investigation and quantification of various interfacial morphologies in Aluminum/Copper and Aluminum/Steel joints, using high-energy phase-contrast synchrotron micro-tomography. Surface topography is extracted from 3D tomographic datasets between dissimilar materials, enabling a comprehensive comparison between different material pairings and various locations within the weld. The study analyses and compares the roughness parameters of these surfaces. Moreover, it describes the interface’s waves and vortexes through diverse morphological metrics, encompassing their shape and size. The results provide evidences that vortexes evolve in three dimensions, with lateral growth and collapse. The waves and vortexes shapes promote material interlocking, increasing the contact area between the dissimilar materials by up to 20%. The interface morphology of Al/Cu joints exhibits higher roughness and a greater number of vortexes compared to Al/Fe joints. Lastly, the findings reveal the presence of interface damage in the form of pre-existing discontinuities.