Potentials of Pulse Magnetic Forming and Joining

Abstract

Magnetic pulse production methods such as forming, joining or separating demonstrate innovative high-speed processes. Such processes can be realized using a capacitor and an appropriate tool coil for forming and welding processes. The process strain rates, which can amount to 20,000 s-1, increase the formability of metallic materials significantly. Magnesium and aluminium alloys find a wider application in the automotive industry due to their light weight potential. Through the low density of these materials, the vehicle weight can be reduced considerably. Due to the hexagonal lattice of magnesium alloys industry-relevant deformation in metal forming processes can only be achieved in hot forming processes. The high-speed forming allows a significant increase of deformability of this alloy. The use of dissimilar metals in an assembly requires the development of innovative joining methods. Apart from being used form and force closure the magnetic pulse welding and adhesive bonding material with different partners is possible. Currently at the Institute for Machine Tools and Factory Management (IWF), TU Berlin, various research topics in the field of pulsed magnetic are investigated. The magnetic pulse sheet metal forming of magnesium alloys at room temperature is investigated in a basic research project. A defined demarcation of high-speed forming with respect to the quasi-static deformation is done by means of hardness measurements in the deformation zone. For this purpose a suitable experimental setup with different matrices is constructed. The experimental results of the pulse magnetic deformation are iteratively compared with simulation results. The aim is to develop a new material model which gives a precise prediction about the high-speed process. In the field of magnetic pulse welding, both basic research and industry-related research projects conducted at the IWF. The process requires an adapted tool coil geometry that meets the requirements of the weld geometry. Different coil geometries and weld geometries and possible applications are presented by way of example, the welding quality is quantified by means of different analytical methods. The material microstructure in the weld zone, characterized by light and scanning electron microscopy shows the typical features of a shock welded joint, as also observed in explosive welding.