Joining of SiC ceramic to Ni-based superalloy with functionally gradient material fillers and a tungsten intermediate layer

Joining of ceramics to metals is of great interest from both technical and economical points of view. SHS welding of SiC ceramic to Ni-based superalloy has been achieved with TiC-Ni functionally gradient materials as filler and a tungsten sheet as an intermediate layer. The obtained welded strength of the welded sample is 60% of the strength of the SiC ceramic measured under the identical conditions. This value is 25% greater than that without the tungsten intermediate layer. Within the range tested in this study, the strength of welded samples increases with increasing thickness of the tungsten layer. The presence of the tungsten intermediate layer can effectively improve the distribution of process-induced thermal stresses in the joints and reduce the concentration of residual thermal stresses in the ceramic near the welding seam. Microstructural study reveals that diffusion takes place at the interfaces, which promotes bonding at the interfaces. (C) 2003 Kluwer Academic Publishers.