Low Cost Method for Synthesis of [100]-W Reinforced Heavy Alloys for Kinetic Energy Penetrators

Single crystals of tungsten (W) with [100] orientation have been demonstrated to exhibit ballistically equivalent performance to depleated uranium (DU) projectiles. Single crystals of W are unfortunately brittle. Also, the state-of-the-art crystal growing techniques limits the diameter of such crystals to less than 10mm. Hence, it is proposed to fabricate tungsten heavy alloy (WHA) projectiles consisting of [100] oriented whiskers/fibers held in a Ni-Fe type matrix. This proposal will address the problems of growing {100] W whiskers/fibers in a heavy alloy matrix. The whiskers/fibers will be grown by the proven VLS process in which MER has considerable expertise (prior experience in growth of SiC and TiB2 whiskers) using a [100] W single crystal substrate, a mixture of WCl6 and H2 as the reactant gases and a Ni-based catalyst (Ni-Fe, Ni-Co, Ni-Cu). The whiskers/fibers will be harvested, cold-pressed and infiltrated in-situ by the catalyst (by varying temperature and atmosphere to promote wetting). This will demonstrate processing that can produce projectiles (>10mm in diameter) for ballistic evaluation. A test scale WHA composite synthesized through the above process will be delivered to the program technical monitor.