Robust Flight Weight Materials for Scramjets

The objective of the proposed Phase II development effort is to establish a material system and robust fabrication methodology to produce ultra-refractory (UF), ceramic matrix composite (CMC) components based on C(f)/HfC90SiC10 compositions for futurescramjet combustors and nozzle liners. The proposed Phase II is split into two distinct efforts. In the first effort, a robust chemical vapor infiltration, fabrication methodology will be developed to ensure reproducibility and good compositional anddensity uniformity throughout the part. In the second effort, 4 distinct fiber architectures will be fabricated and tested to determine thermo-mechanical properties and durability during exposure to a simulated scramjet combustion environment. In anoptional period, flight-weight hardware will be fabricated for a sub-scale flight test early in 2005.The conclusion of this Phase II effort will be a significant risk reduction in the use of UR CMCs for flight weight, scramjet engine components. The survivability will be confirmed under representative conditions and the issues of surface roughness on theaerodynamic vehicle drag will be evaluated leading to a better understanding as to the effect of these materials on the vehicle stability during flight. The hardware built under this program will be flight tested under another program.