JOINING OF SiC CERAMIC TO Ni-BASED SUPERALLOY BY SELF-PROPAGATING HIGH-TEMPERATURE SYNTHESIS (SHS) WITH TUNGSTEN INTERMEDIATE LAYER

摘要

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 realized with TiC-Ni functionally gradient materials as filler and a tungsten sheet as intermediate layer. The obtained bending strength of the welded sample is 60% of the strength of SiC ceramic measured under the identical conditions. This value is 25% more than that without the tungsten intermediate layer. Within the range tested in this study, the strength of welded sample increases with increasing the thickness of the tungsten layer. The experimental results indicate that the residual stress decreases significantly by inserting the intermediate layer. Microstructural study reveals that diffusions take place at the interfaces, which promote bonding at the interfaces.