Diffusion bonding of nickel aluminide Ni75Al25 using a pure nickel interlayer

Diffusion bonding of Ni75Al25 using nickel as interlayer was carried out at 1000 °C under vacuum for various hold times. The microstructure of transition joints was revealed by scanning electron microscopy (SEM). Micrographs showed that a sound bonding formed continuously along the interface. Chemical compositions of the nickel interlayer and the bond interface were determined using energy dispersive spectroscopy (EDS) and X-ray diffraction studies were made on the fractured surface of all the specimens. Results demonstrated that interdiffusion between the nickel interlayer and the matrix was significant. The maximum shear strength was found as 233 MPa for bonded sample treated for 4 h.