Transient liquid phase (TLP) bonding of Inconel-738 LC superalloy was investigated using AMS 4777 filler alloy.
The bonding was performed at 40 and 80 μmgap sizes at sufficient time in order to achieve complete isothermal
solidification. Solution treatment (1120 °C/2 h) was carried out in two different sequences, one before and the
other after TLP bonding of the base metal accompanying subsequent aging treatment (845 °C/24 h) which are
called HT-A and HT-B, respectively. In both cases, nomorphological changes in diffusion affected zone (DAZ) precipitateswere
observed. However, line scan analysis indicates enrichment of basemetal alloying elements (Ti, Al)
at isothermal solidification zone (ISZ) of heat treated samples, particularly HT-A joints resulted in increased hardness
of the centerline. In addition, improved shear strengthwas seen in heat treated joints conforming to the ductile
fracture surfaces. The maximum hardness of 759 Hv and the highest shear strength of 565 MPa in the joint
area, were found in HT-A condition with 40 gap size. Enhanced mechanical properties were mainly controlled
by solid solution strengthening mechanism.