Vacuum TLP bonding of Inconel 617 superalloy using Ni-Cr-Si-Fe-B filler metal: Metallurgical structure and mechanical properties

In the present paper, vacuum transient liquid phase bonding of Inconel 617 alloy was studied. The experiments were carried out at 1135 °C for two different holding times of 45 and 300 min, and using Ni-Cr-Si-Fe-B filler metals with 50 and 100 μm thicknesses. The microstructure, shear strength, and microhardness of the resultant joints were investigated. The results showed that the complete isothermal solidification occurred after 300 min for both the filler metal thicknesses. The presence of eutectic phases and cavities in the interlayer and non-dissolved carbides in the diffusion affected zone were the main reasons for the reduction in the shear strength. By increasing the holding time, the carbides were dissolved and the hardness of the diffusion affected zone was reduced. The highest shear strength was obtained for the 50 μm thick interlayer and 300 min holding time (with about 96% joint efficiency).