Novel Brazing Technology for Joining and Sealing of CMC/Monolithic Turbine Vanes

"Foster-Miller and GE Aircraft Engines (GEAE) have been working together for years on the next generation ceramic matrix composite (CMC) airfoils required to reach the IHPTET performance goals. Smaller turbines, such as in the Joint Turbine Advanced GasGenerator (JTAGG), have particularly demanding performance requirements. One area of critical development is the trailing edge of the JTAGG high pressure turbine vane, which demands a monolithic ceramic knife edge while maintaining the CMC leading edgeperformance.On the proposed effort, Foster-Miller and GEAE will team to develop a unique brazing technique to overcome a significant thermal mismatch in order join a monolithic Si3N4 trailing edge to a 3D braided SiC/SiC leading edge. The team's extensive CMC airfoildevelopments, combined with Foster-Miller's long history of braze development for ceramics and other unique materials, will enable the development of a highly reliable joint and seal for this vital component.During Phase I, Foster-Miller will develop the braze materials and geometries, and will verify their effective strength with shear testing. Phase II optimize the braze materials and demonstrate the joining technology of the full size component.(P-020007) The joining technology developed here will enable high temperature performance in highly loaded turbine vanes. The target JTAGG engine, as well as larger IHPTET and VAATE demonstrators, can also benefit from the develo