Description:
Description C Increasing weapon lethality for the individual soldier has been a long-standing goal of the US Army. Tungsten carbide (WC) is a common material used in many small caliber armor-piercing projectiles. These projectiles act as rigid bodies during impact at 0 degrees obliquity and achieve twice the penetration depth of equivalent depleted uranium and tungsten heavy-alloy projectiles. However, at impact obliquities other than 0 degrees the performance dramatically drops due the tensile stresses imparted on the surface of the WC core by the bending moment generated upon impact. Identification of WC materials with high strength and fracture toughness can lead to improved lethality in many weapons systems. Unfortunately the WC materials used as projectiles typically contain a cobalt (Co) matrix. While these materials have high density, hardness, strength and fracture toughness Co is a strategic and critical material that the US Department of Health and Human Services has classified as reasonably anticipated to be a human carcinogen in 2011 [1]. Efforts need to be initiated to indentify non-hazardous alternatives to Co that will yield WC materials with the necessary properties for use as armor-piercing projectiles. Phase I C Study and demonstrate the feasibility of a procedure to produce a WC material with high density ( & #8805; 14 g/cm3), flexure strength (Y 3 GPa), a fracture toughness (Y 11 MPam) and a minimum Knoop hardness, using a 2 kg indentation load, of 15 GPa. The WC material is not permitted to contain any additives that are deemed carcinogens or are long-term hazards to human health. The desired process must be able to produce WC material in a cylindrical rod form with a diameter of 5.56mm ( 0.008 mm). The proposer would be expected to report and if successful demonstrate a process for making a 500mm long rod without bowing while maintaining dimensional integrity over the entire length of the rod. Phase II C Building on the results of a successful Phase I effort, improve the procedure for fabricating rods of the WC composition from Phase I to further enhance the flexure strength and fracture toughness by 20% over the Phase I goals without a decrease in Knoop hardness. Quantify and qualify the performance of the WC material by generating quasi-static property data (flexure strength, fracture toughness, hardness, density) using appropriate standard procedures. Perform a cost analysis assessment for future production. Reasonable performance related goals expected to be achieved by the proposer related to the execution of this project are the demonstration of the selected WC production process through the generation and delivery of five (5) prototype WC rods 500mm long. These rods will be delivered to the US Army Research Laboratory (ARL) for evaluation. Similarly, a successful second year of this Phase II effort could be expected to demonstrate and deliver five (5) additional WC rods 500mm long as well as 25 near-net shape projectiles having a diameter of 5.56mm ( 0.008 mm) with a length and nose geometry specified by the Army POC. These rods and projectiles will be delivered to ARL for evaluation. Phase III C Ultimately the procedures developed during the performance of this SBIR for manufacturing WC small-arms projectiles will then be scaled and applied to other caliber projectiles such as the 7.62mm and 50 cal. This development could change the state-of-the-art for individual soldier lethality as we know it, with tremendous savings realized by the Army because of increased lethality. PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: Cemented tungsten carbide is widely used in the commercial sector for cutting tools, saw blades, wear-resistant components in industrial machinery, sporting goods, and surgical equipment. In all these applications having additional cobalt-free alternatives would be highly desirable and competitive.
