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

Foster-Miller and GE Aircraft Engines (GEAE) have worked extensively to develop ceramic matrix composite (CMC) fabrication techniques for high temperature airfoils. GEAE's latest high pressure turbine (HPT) nozzle designs require CMCs and monolithics tomeet the goals of the Integrated High Performance Turbine Engine Technology (IHPTET) and Versatile Advanced Affordable Turbine Engine (VAATE) programs, for turboshaft and future Unmanned Air Vehicle (UAV) engines.On Phase I, Foster-Miller successfully demonstrated joining monolithic Si3N4 to SiC/SiC CMCs using advanced brazing methods. In Phase II, Foster-Miller will team with GEAE to further develop these joining methods for CMC to CMC joining for the HPT nozzle.The proposed program will develop the materials, geometry, and manufacturing of the braze to join a SiC/SiC leading edge to the SiC/SiC bands. The Phase II program will culminate in full-size component fabrication at Foster-Miller and testing in GEAE'sburner rig.The development of the brazed hybrid airfoil nozzle joining will enable GEAE to meet its target weight and cost reduction goals for UAV engines, for IHPTET and VAATE designs. Additionally, the development of this brazing method will enable the joining ofCMCs to like airfoils, monolithics, or metal cooling air supply. (P-020464)The joining technology developed here will enable high temperature performance in highly loaded turbine vanes. The target UAV engine, as well as larger IHPTET and VAATE demonstrators, can also benefit from the development of this airfoil fabricationmethod. Additionally, as CMCs are introduced into other high temperature applications, the braze methods developed here can be used in order to join adjacent components, be it CMC to CMC, CMC to monolithic ceramics, or CMC to metals.