Non-Eroding Fin Materials

The fins of Army hypervelocity missiles are situated within the exhaust plumes. This creates a unique fin erosion environment consisting of a combination of high temperature gases plus particulates of aluminum oxide solid fuel particles. Several approaches are available for the design of low eroding rate missile fins. Both single material and multi-material design constructions are possible, and potential material types include monolithic refractory metals, monolithic ceramics, and refractory composites consisting of carbon fiber reinforced carbide, oxide, or boride matrices. The material requirements for the non-eroding fin materials include low mass density, high strength, good erosion resistance (i.e. hardness at elevated temperatures), good oxidation resistance, high melting temperature, high thermal shock resistance, and chemical incompatibility with the aluminum oxide present in the rocket exhaust. In multi-material design configurations and for the case of refractory composite materials, low residual stress after processing will contribute to the ability of the designs to achieve high strengths. The tasks to be performed in this program include defining design requirements; selection, design, and analysis of candidate materials; preliminary design of non-eroding fin configurations; and recommending materials and formulating test plans for Phase II continuation.