Electromagnetic Pulse Welded Aluminium to Copper Sheet Joints: Morphological and Mechanical Characterization

摘要

This study investigated joining of Al to Cu sheets by electromagnetic pulse welding, whichis a solid-state welding process that uses electromagnetic forces to join materials. Theinterfacial morphology and mechanical properties of the Al/Cu joints were analysed andrelated to the welding process parameters. The centre section of the Al/Cu joints evolvedfrom a non-welded to a welded zone. The welded zone started with a wavy interface,consisting of thick interfacial layers with defects and evolved to a relatively flat interfacewithout an interfacial layer. Interfacial phases resulted from solid-state mechanical mixingand/or very localised interfacial heating. The interfacial layers had a thickness rangingfrom 2-39 μm, an interface waviness amplitude up to 11 μm and contained 31-75 wt% Cu.The interfacial layer thickness and the weld length are determined by both the dischargeenergy and the stand-off distance. A trade-off existed between a homogeneous interfaceand the maximum weld length when the stand-off distance is changed. The interfacial layerexhibited an increased hardness compared to Al and Cu. A higher tensile force, up to4,9 kN, was achieved at a higher energy and a lower stand-off distance. One of the factorsdetermining the tensile force was the width of the welded area.