Interfacial Microstructure of Aluminum/Metallic Glass Lap Joints Fabricated by Magnetic Pulse Welding

Abstract

Magnetic pulse welding was applied to the lap joining of crystalline pure aluminum and metallic glass (Zr₄₈Cu₃₆Al₈Ag₈ and Cu₅₀Zr_42.5Al_7.5) and interfacial microstructure was examined. The metallic glass fractured in brittle manner in conventional plate layout. However, Al/metallic glass joints were successfully obtained without fragmentation of brittle metallic glass by setting a soft aluminum plate as a shock absorber behind the metallic glass. The welding interface exhibited characteristic wavy morphology as well as that of metal/metal joints. Thin layer with medium chemical composition of the metallic glass and Al was also produced at the welding interface. No chemical composition change took place in the area of 2 μm and more away from each matrix/intermediate layer interface. Also, no hardness change of Al matrix was detected in the area of 2 μm and more away from Al/intermediate layer interface. Hardness of metallic glass matrix close to the welding interface was not constant, however, TEM observation revealed that the metallic glass matrix retained the amorphous structure after the welding. These obtained results are considered to indicate that the metallic glass did not crystallize after the magnetic pulse welding.