Innovative Nosetip Materials and Designs for Hypervelocity Projectiles

The Navy is developing high speed projectiles for a variety of missions including ship defense, surface fire support, and prompt global strike. Inertial loads and high muzzle velocities impose severe operational conditions on the nosetips and suggest they should be made from refractory metals. While metals provide sufficient density for aerodynamic stability, they react to form low melting compositions that can damage the projectile. Other high temperature materials like graphite or carbon-carbon are too light to maintain stability. The proposal seeks to develop multi-material nosetip designs that employ a thin coating or small tip applied to a dense substrate. The Phase I program will select substrate and coating materials to address thermochemical stability and projectile performance. A preliminary trade study will rank important material parameters by using thermostructural equations to compute inertial stresses, temperatures, and thermal stresses. Fabrication techniques considered in the Phase I will include adhesive bonding, brazing, and HIP-induced diffusion bonding. In the Base effort nosetip configurations will be selected and fabricated. In the Option, they will be evaluated with tensile and flexure tests of bonded interfaces. The Phase I effort will be performed by Materials Research & Design, Inc. (MR & D), Exothermics, and Southern Research Institute (SoRI).