Local Microscopic and Integral Macroscopic Analysis of Magnetic Pulse Welds and Deformations for Dissimilar Metal Joints
Magnetic pulse technology is used for high-speed forming as well as for joining. Joining by magnetic pulse welding (MPW) is the combination of high-speed forming, impact, and a resulting weld in the collision zone of the accelerated flyer and the impacted target. This MPW process allows the welding of dissimilar metals, like aluminum and steel for lightweight construction or aluminum and copper for E-mobility applications. Investigations showed up scattering in binding strength and failure for comparable welds. The effects leading to the bond formation and the reasons for the quality variation are not fully understood until now. For further understanding, a combined experimental investigation of integral and local mechanical weld properties supported by simulations and microstructure analysis was performed considering dissimilar metal joints of aluminum EN AW1050 H14/24 and copper Cu DHP R240 for different configurations and impact energies. Lap shear tests served for quantifying integral mechanical properties, while local mechanical properties were determined by microtensile tests on samples prepared in the thickness direction of the welded metal sheets and microstructural analysis. These local microscopic testing and analysis results provide information about the weld strength distribution. These investigations give new hints on the bond-forming mechanisms and local process depending on material effects.