SiC SiC Fasteners

TDA Research is proposing to develop silicon carbide fiber – silicon carbide matrix (SiC/SiC) fasteners that can be used to join ceramic matrix composite (CMC) components to metal components. CMCs are increasingly replacing metal components in aircraft propulsion systems because they are lighter, more durable and can operate at higher temperatures. Engines with CMC components are more efficient (higher performance), but joining the CMC components to metallic frames and residual metal components is challenging. Laminated (2D) CMC fasteners with rectangular cross sections fail due to delamination. TDA proposes to develop a near-net shape braiding process with the fastener head integrally braided into the woven architecture of the cylindrical fastener body. The braided fibers in the preform will then be then be coated with a layer of boron nitride, followed by a layer of silicon nitride. The fastener will then be densified through a polymer impregnation and pyrolysis process to provide a SiC matrix.