Controlled Fragmentation QIM WHA-Warhead Fabrication with Integrated Aluminum Pusher Plates

Due to their high density, tungsten heavy alloy (WHA) materials are highly desirable for controlled fragmentation (CF) warheads. A high-density material CF warhead can produce smaller fragments with higher kinetic energy for improved lethality with a higher area density (particles in a given volume). However, WHA materials' high strength, brittleness, and hardness make the fabrication of CF warheads complex by traditional machining and forming means.  Phase I demonstrated promising results for a CF WHA warhead that was fabricated by the CPS Quickset Injection Molding (QIM) Process.  Phase I included integration of an aluminum metal pusher plate which was overcast with the CPS molten aluminum metal pressure infiltration process. In detonation testing controlled fragmentation was demonstrated in these initial test warheads. The fragment weight was estimated to be 2.25 grains based upon design.  The measured velocity of fragments 3300 fps.  Phase II will further materials development alloy optimization, production scale-up utilizing commercial QIM machines, improved sintering processing, CF design optimization, and developing the integrated Al-overcast pusher plate assembly.  CPS will collaborate with the New Mexico Institute of Mining and Technology, Energetic Materials Research and Testing Center (EMRTC) on process improvements and design configurations with static detonation testing to evaluate fragmentation velocity and fragment distribution, fragmentation pattern, and Al metal overcast pusher-plate design parameters  Observations of performance as a function of materials properties, design, and microstructure will be used to develop design rules for this application.    The Phase II technical objective are to manufacture CF WHA warhead design(s) capable of MK-19 40 mm warhead applications, reaching a narrow and predictable fragment size distribution of 1.5 – 2.0 grains at the highest material WHA density possible > 18.0 g/cm3.  The fragmentation velocity must be between 1 – 1.2 km/s (3000 – 4000 fps): fragmentation must have a uniform areal particle density after detonation to achieve a predictable lethality zone.  The developed process will be optimized for high-volume manufacturing by consideration of input materials, sintering mechanisms, and product design.  This methodology is anticipated to be applicable for high-density powder metals and composite systems like steels, copper, CuMo, CuW, and WC, in addition to WHA.