Abstract: The Ni-base single crystal superalloy was bonded by the transient liquid phase (TLP) bonding, using a Ni-base flexible metal cloth as an insert alloy. TLP bonding of superalloy was carried out at 1473~1523 K for 0.5~24 h in vacuum. The [001] orientation of each test specimen was aligned perpendicular to the joint interface. The bonded region was observed by optical microscopy, and the microstructural and compositional analyses across the bonded interlayer were performed by using a scanning electron microscopy (SEM). The electron back scattering diffraction (EBSD) method was applied to determine the crystallographic orientation. The results indicated that the chemical homogeneity across the bonded region can be achieved, and γ′ phase both in the bonded interlayer and in the superalloy substrate is almost identical, while the bonded interlayer had almost matched the crystallographic orientation of the bonded substrates.

Key words: Single crystal superalloy, TLP bonding, Microstructure, Crystallographic orientation