Electrically Driven Plasma via Vaporization of Metallic Conductors: A Novel Tool for Joining Tubular Workpieces

Electrically driven rapid vaporization of thin aluminum wires is an innovative forming process. In this manuscript, joining of tubular workpieces by expansion using this technique is investigated. The goal is to identify the influence of major process parameters, like input energy and discharge frequency on the workpiece deformation, the forming velocity, and the resulting joint strength. Therefore, free-forming as well as joining experiments were conducted. During these experiments, thin aluminum wires were intentionally vaporized in the center of aluminum tubes. The pressure was transmitted from the region of vaporization to the inside wall of the tubes via an elastomer medium. In the free forming experiments it as found that, at the same charging energy level, a decrease of the discharge's rise time leads to an increase of the maximum velo ity. Therefore, the discharge frequency was found to have a positive effect on process efficiency. The joining experiments led to strong interference-fit connections, whose strength increased proportionately with increasing input energy.