Ultrasharp CMC Leading Edges Using Three-Dimensional Fiber Reinforcement

As the radius of curvature of a leading edge or nosetip decreases, the drag on the body decreases, leading to more efficient flight, but the heat flux at the stagnation point increases. Hypersonic leading edges therefore require materials that can be formed into complex shapes with fine features while simultaneously being able to handle extreme temperatures and mechanical loading. In this project, Ultramet will build on previous work in which carbon fiber-reinforced silicon carbide matrix (Cf/SiC) ceramic matrix composites (CMC) with three-dimensional fiber reinforcement were fabricated with edge radii on the order of 0.010". The same fiber architecture and preforming techniques will be used, and the preform will again be densified via melt infiltration. Rather than using a SiC matrix, however, the proposed project will use matrices such as zirconium carbide (ZrC) and/or hafnium carbide (HfC), which have higher temperature capability than SiC as demonstrated by arcjet and laser testing. The result will be a sharp fiber-reinforced ceramic leading edge with excellent high temperature capability.