Ceramic Matrix Composite Fins and Nosetips for Gun-Launched Projectiles

Boeing Defense Systems is developing a guided hypervelocity projectile (HVP) and associated integrated launch package assembly. The nosetip and fixed and rotating fin components present particular challenges due to the high aeroheating and dynamic pressure loads and associated temperatures, thermal shock, and oxidizing conditions. Low drag requires sharp tip and edge features on the nose and fins, which leads to high thermal stress levels due to the extreme temperature gradients that develop after exiting the gun. In previous work for MDA, the Army, Navy, Air Force, and NASA, Ultramet demonstrated the fabrication of carbon fiber-reinforced refractory carbide matrix composites for hypersonic vehicle airframe applications using a rapid, low-cost melt infiltration process. The composite materials have undergone extensive modeling and high temperature testing under laser and arcjet heating conditions and have exhibited low or no erosion when tested up to 5200°F. The composites have also exhibited extremely high toughness and thermal shock resistance and have demonstrated good potential for operation in adverse weather. In this project, Ultramet will team with Boeing to optimize the high temperature melt infiltrated carbon fiber-reinforced zirconium carbide matrix composite in terms of material and attachment to maximize HVP thermal/mechanical/oxidation operating capability, thereby increasing survivability and lethality.