An investigation on diffusion bonding of aluminum and magnesium using a Ni interlayer

Abstract Diffusion bonding aluminum and magnesium using a Ni interlayer was investigated for the first time. The bonding trials were carried out at 440 °C for different time under 1 MPa in a vacuum of 6 × 10 − 3 Pa. The interfaces were investigated by means of SEM, EPMA, XRD and Vickers hardness test. The results showed that dissimilar metals of Mg/Al could be successfully joined by diffusion bonding with a Ni interlayer and the Mg–Al intermetallic compounds were impeded. From Al side to Mg side, there was Al substrate, Al–Ni reaction layer, Ni interlayer, Mg–Ni reaction layer, Mg substrate. The microhardness in the Al–Ni reaction layer and Mg–Ni reaction layer increased sharply, which were 201.5 Hv and 244.1 Hv. The fracture occurred in the intermetallic compound layer of the Mg–Ni reaction layer, where the Mg 2 Ni phase appeared on both Al and Mg surfaces.