Ultrafine grained tungsten heavy alloy kinetic energy penetrators

For quite some time, a suitable replacement for the environmentally harmful depleted uranium (DU) for use as long rod penetrators has remained elusive. Tungsten based heavy alloys, commonly termed WHAs, with a tungsten grain size in the several tens ofmicrons, come close to the performance of DU for kinetic energy (KE) penetrators in general, but fall short when the L/D ratio is > ~ 10. Recent studies have shown that when the grain size is reduced by more than an order of magnitude, the mechanicalbehavior under dynamic loading conditions can be very different. Since the dynamic mechanical behavior is directly related to the performance of armor piercing penetrators, new processing technologies are required to develop WHAs with an ultrafine grainedstructure. In this program, we propose to develop a new generation of ultrafine grained KE penetrators using recent innovations (i) in the synthesis of nanocrystalline powders of tungsten alloys, and (ii) in powder consolidation using microwave energy. InPhase I, processing parameters will be developed and samples will be produced for structural characterization and testing of mechanical properties. In Phase II, the consolidation technology will be scaled to L/D > 12 with D = ~ 10 mm, or as desired by theArmy. Samples produced under optimized conditions will be provided to the Army for testing in the field. The principles employed in powder synthesis and powder consolidation are generic, and will apply to materials that are generally difficult to process.For example, tantalum has several functional and structural applications, but is difficult to be processed. Therefore, we expect our program to have wide ranging implications in a number of application areas, although this specific program is geared towarda specific DoD need.