An improvement has been made to the infiltration of 3D woven and 3D braided preforms that will lead to the manufacture of CMC (ceramic matrix composite) and C–C (carbon-carbon) composites based on 3D fiber architectures that have low residual porosity and smaller void sizes. Tailoring the fiber architectures by the use of several combinations of larger and smaller warp, fill, and z yarns formed pathways into the thickness of the fabrics to improve fluid flow through the preform during CVI (chemical vapor infiltration) processing.
CMC materials based on 3D fiber architectures have greater impact resistance as well as a longer fatigue life, which is useful for reusable launch vehicles. The improved infiltration technique should also apply to PIP (polymer infiltration and pyrolysis) processing.
When coupled with PIP, the 3WEAVE® process is capable of making large CMC parts, several meters in width and tens of meters in length. The enhanced impact tolerance improves safety of the acreage thermal protection systems (TPS). The 3BRAID® process can make smaller shapes with near net shape geometries and integral stiffeners, allowing for flexibility in the design of CMC leading-edge shapes. Simpler geometries or larger leading edges can be based on 3WEAVE® preforms. Also, components such as rocket nozzles and other propulsion structures are better able to withstand large temperature gradients without delamination if based on 3D fiber architectures. This innovation is suitable for any high-temperature application where components must withstand impact or require a longer life at high temperatures.