Fabrication of Ta-Hf-C-based Ultra High Temperature Composites via a

This Phase I STTR program seeks a new fabrication method to produce stronger (>100 kpsi) and tougher (>10 MPa m1/2) ultra high temperature Ta-Hf-C-based composites (UHTC) with an outstanding oxidation resistance for use as thermal protection systems for hypersonic applications, as well as for advanced rocket nozzle throat components. UES will apply a novel "Top Down" approach to control the microstructures of the composites. This approach will produce a very unique grain structure that can offer high strength, high fracture toughness, and high oxidation resistance. Hot-pressing will be used as a means for densification during the Phase I feasibility study. In the Phase II work, a sinter/HIP process will be explored for near-net shape fabrication. During the Phase I program, UES will collaborate with the University of Alabama to evaluate oxidation mechanisms and to conduct microstructural characterization. UES will process the powders and will also evaluate the mechanical properties.