Microstructure and strength of diffusion-bonded joint between nickel aluminide Ni_(75)Al_(25) and AISI 316 L stainless steel using a nickel interlayer

摘要

Diffusion bonding between nickel aluminide Ni_(75)Al_(25) and 316 L austenitic stainless steel using a nickel interlayer was carried out at 1000 deg C under vacuum for various hold times. The microstructures of the interface of joints were analysed by optical and scanning electron microscopy (SEM). Micrographs demonstrated that excellent bonding formed continuously along the interface. Chemical compositions of the interface of the bonded samples were determined using energy dispersive spectroscopy (EDS) and X-ray mapping studies were made on the fractured surface of all the specimens. Analysis results showed that reaction occurred between the base metals and the nickel interlayer. After welding process, shear tests applied to the bonded samples to determine shear strength of joints. Test results indicated that the maximum shear strength was 238 MPa for the bonded sample treated for 4 h.