Lightweight Ultrahigh Temperature CMC-Encased C/C Structure for Reentry and Hypersonic Applications, Phase II

Future reentry and hypersonic vehicles require advanced lightweight leading edge thermal protection systems that can provide the dual functionality of thermal/oxidation protection and structural capability. In Phase I, Ultramet demonstrated the feasibility of combining the light weight of carbon/carbon (C/C) with the long-duration oxidation resistance of ceramic matrix composites (CMC) in a unique laminate composite structure. This structure, composed of a C/C body with an integral CMC casing, effectively bridges the gap in weight and performance between coated C/C and bulk CMCs. Fabrication and initial performance of this laminate composite structure was demonstrated through an innovative variant of Ultramet's melt infiltration refractory composite processing technology. In its bulk form, this same CMC has survived >4300oF liquid propellant rocket engine testing at NASA GRC and >5200oF hot-gas testing at the Air Force LHMEL facility. Application of this reinforced ceramic material to a predominantly C/C structure would create a highly innovative material with the potential to achieve the long-sought goal of long-term, cyclic, high-temperature use of C/C in an oxidizing environment. In Phase II, Ultramet will team with Lockheed Martin and Pratt & Whitney for process optimization and comprehensive testing of this lightweight, high strength, ultrahigh temperature oxidation-resistant material system. The fully developed system will have strength that is comparable to that of C/C, low density comparable to that of C/SiC, and ultrahigh temperature (>4000oF) oxidation stability. It will not only be able to withstand the aggressive environments that are encountered by reentry and hypersonic vehicles, but also will have the structural capability required for advanced airframe and engine components.