High Density Nosetips for Hypersonic Projectiles

The Navy is developing weapon systems capable of launching inert projectiles for long-range surface fire support and missile intercept applications. Inert projectiles offer significant logistical and safety advantages over conventional chemical propellants or explosive ordnances. The launch conditions of future hypersonic projectiles will put extreme mechanical and aerothermal loads on the projectile nosetip. These conditions combined with the high-density requirements present a significant materials challenge. No economical monolithic component is projected to survive the extreme conditions immediately after projectile launch, followed by less severe conditions during flight to target. The objective of this proposed effort is to develop and demonstrate an innovative multi-layered material system that is capable of surviving the extreme conditions immediately after projectile launch, followed by less severe conditions during flight to target. The concept is based on a tungsten core with a fracture tough oxidation resistant coating and an outermost sacrificial layer. An ablative layer is intended to dissipate absorbed thermal energy from aerothermal loading, thereby limiting steep thermal gradients in the underlying oxidation protection layer. Thermo-structural modeling will guide the selection of appropriate materials and geometries for each layer. Upon completion of modeling, demonstration articles will be fabricated and evaluated via microstructural characterization and high heat flux testing.