Diffusion induced isothermal solidification during transient liquid phase bonding of cast IN718 superalloy

AbstractIn transient liquid phase (TLP) bonding for commercial applications, one of the important key parameters is the holding time required for complete isothermal solidification tIS, which is a prerequisite for obtaining a proper bond microstructure. The objective of the study is to analyse the isothermal solidification kinetics during TLP bonding of cast IN718 nickel based superalloy. Experiments for TLP bonding were carried out using a Ni–7Cr–4·5Si–3Fe–3·2B (wt-%) amorphous interlayer at several bonding temperatures (1273–1373 K). The time required to obtain TLP joints free from centreline eutectic microconstituents was experimentally determined. Considering the solidification behaviour of residual liquid, tIS could be predicted by a mathematical solution of the time dependent diffusion equation based on Fick’s second law.Dans la brasure en phase liquide transitoire (TLP) pour applications commerciales, l’un des parametres cles importants est le temps de maintien requis pour la solidification isother...