The joining of Inconel 718 superalloy was achieved by transient liquid phase (TLP) bonding and utilising a BNi-2 interlayer material. The microstructural changes and high-temperature tensile behaviour of IN 718 joints were investigated in detail. The microstructure of the bond interface was investigated using Field Emission Scanning Electron Microscope (FESEM) analysis. The microstructure observed after bonding reveals the presence of intermetallic compounds within the isothermally solidified zone (ISZ). A high volume of intermetallic compounds in the ISZ adversely affects the strength of the joint. Post bond heat treatment (PBHT) was applied to homogenise the bond microstructure and remove intermetallic compounds present in the ISZ. Implementing PBHT improves both the microstructural homogeneity and strength of the IN 718 joint. Uniform chemical composition was obtained in the PBHT sample. The fraction of borides present in the diffusion affected zone was reduced through the PBHT. At 650 °C, the PBHT sample exhibited 96% of the strength of the heat-treated base material with a concomitant reduction in ductility. The fracture surface reveals that the crack initiates near the boundary of the ISZ and the diffusion affected zone.
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