Microstructural evolution during transient liquid phase bonding of Inconel 617 using Ni-Si-B filler metal

The influence of process parameters on microstructural characteristics of transient liquid phase (TLP) bonded Inconel 617 alloy was investigated. Experiments were carried out at 1065 degrees C using nickel based filler metal (Ni-4.5% Si-3% B) with B as the melting point depressant (MPD) element. Two different thickness of interlayer and various holding times were employed. The influence of these processing parameters on the characteristics of the joint area particularly size, morphology and composition of precipitates was investigated. The presence of MoB, Mo2B, M23C6, TiC, M23(B, C)(6) and Ni3B precipitates in the diffusion layer and Ni3B, Ni3Si and Ni5Si2 precipitates in the interlayer at the interface between the base metal and interlayer were demonstrated using electron back scattered diffraction (EBSD), energy dispersive spectrometry (EDS) and TEM. (c) 2006 Elsevier B.V. All rights reserved.