Refractory Metal-Lined Composites for Lightweight High-Performance Propulsion omponents 2000-01-1720

Requirements for advanced rocket propulsion systems are becoming increasingly more demanding. The use of high temperature capable materials in such systems, including applications in liquid rocket engines and solid rocket motors, offers potential benefits of increased performance and/or efficiency based on the engine operating cycle. For the ultimate in high temperature capability, refractory metals, ceramics, ceramic matrix composites (CMCs), and carbon/carbon (C/C)composites each provide particularly beneficial attributes, but with selected limitations. Refractory metals are relatively tough and durable, provide impermeable structures, and can be conventionally fabricated, but are relatively dense, leading to heavyweight structures. Monolithic ceramics generally lack desired toughness and durability. CMCs offer substantially improved toughness over their monolithic counterparts and are relatively lightweight, but are permeable and difficult to join to conventional structures. C/C is extremely lightweight, but lacks resistance to the operating environment and is also permeable. Metal-lined, composite-jacketed structures have the potential to combine the beneficial characteristics of metals with the light weight and high temperature resistance of CMCs or C/C. In the current work, prototype refractory metal-lined C/C structures were designed, fabricated, and successfully ground tested in a representative liquid rocket engine environment. No leakage or permeability was exhibited. Successful joining was achieved to the mating structure, and cost-effective fabrication was demonstrated using an “inside-out” processing technique. Projected full-scale component weight was similar to that for conventional materials employed in similar applications. This approach, when matured, offers the potential for fabrication of lightweight, durable, and cost-effective advanced rocket propulsion components.