TLP bonding of Ni-base single crystal superalloy

The DD98 single crystal superalloy was bonded by transient liquid phase(TLP) bonding, in which a Ni base flexible metal cloth was used as an insert alloy. TLP bonding of DD98 superalloy was carried out at 1473-1523 K for 0.5-24 h in vacuum. The melting characteristics of the interlayer was determined using differential thermal analysis(DTA). 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 joint zone consists of a bond, diffusion and base regions, and the gamma' phases both in the bonded interlayer and in the superalloy substrate are almost identical and the orientation relationship between the bonded interlayer and the bonded substrate has a good match.