Investigation of Linear Stability Theory for Wavy Interface in Magnetic Pulse Welding

Magnetic Pulse Welding (MPW) is a solid state, high strain-rate joining process in which a weld of dissimilar or similar materials can be created via high-speed oblique impact of two workpieces.~ MPW is a lap welding method:~ the two workpieces are placed in a roughly parallel configuration with a small gap between them to achieve high impact velocity and pressure.~ Intriguingly, experiments routinely show the emergence of a distinctive wavy pattern, with a well defined amplitude and wavelength of approximately 20 and 70 micrometers, respectively, at the interface between the two welded materials.~ The mechanism underlying this wavy pattern is still not well understand.~ Some researchers have proposed that the interfacial waves are formed in a process akin to Kelvin-Helmholtz instability, with relative shear movement of the flyer and base plates providing an energy source for the vortical pattern. Here, we employ a linear stability analysis to investigate whether the wavy pattern could be the signature of a shear-driven high strain-rate instability of a perfectly plastic solid material.~ Preliminary results confirm that an instability giving rise to a wavy interfacial pattern is possible.