Metal Injection Molding for Improved Tungsten Fragmentation Warheads

RT&L FOCUS AREA(S): General Warfighting Requirements (GWR) TECHNOLOGY AREA(S): Weapons, Materials The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), 22 CFR Parts 120-130, which controls the export and import of defense-related material and services, including export of sensitive technical data, or the Export Administration Regulation (EAR), 15 CFR Parts 730-774, which controls dual use items. Offerors must disclose any proposed use of foreign nationals (FNs), their country(ies) of origin, the type of visa or work permit possessed, and the statement of work (SOW) tasks intended for accomplishment by the FN(s) in accordance with section 3.5 of the Announcement. Offerors are advised foreign nationals proposed to perform on this topic may be restricted due to the technical data under US Export Control Laws. OBJECTIVE: Investigate and demonstrate tungsten medium caliber fragmentation warheads made with Metal Injection Molding (MIM) for improved performance and reduced cost. DESCRIPTION: Tungsten is being used to improve the lethality of warheads due to its higher density. Because it is difficult to machine, tungsten powder is being pressed and sintered into preformed fragments, and then cast into warheads using a resin or metal matrix. There are many steps and there is significant labor involved, resulting in much higher costs for the increase in performance. Injection molding is one of the lowest cost manufacturing processes due to the very high throughput and consistency. Metal injection molding utilizes the same process to injection mold metal powders with a resin binder into small complex parts which can then be debinded to remove the resin and sintered into a solid metal part. These steps are largely automated in batch or conveyor processes. It is most cost effective for making small, complex, difficult to machine parts with high cost materials in large quantities. MIM could be utilized to make tungsten medium caliber warheads with internal features to optimize fragmentation for increased performance at a lower cost than other methods. One technical challenge is the possible need for a pusher plate to contain the explosive reaction as the warhead expands, to optimize the transfer of the energy into the fragments instead of between them. Forming the fragment body with the pusher plate into a monolithic structure could provide an additional cost and performance improvement. PHASE I: During Phase I, MIM tungsten samples will be procured to perform feasibility testing. Testing will determine if MIM tungsten has the physical properties to properly fragment, if a pusher plate is required to achieve the desired performance, or if MIM tungsten is inappropriate for this application. Test results and further material analysis of the MIM tungsten will drive initial design work for a MIM tungsten warhead to be fabricated in Phase II. Based on test results, material evaluation, Picatinny's ability to load warheads, and upcoming programs which may be leveraged, a warhead will be selected for MIM tungsten prototyping (most likely 40mm grenade, 30mm autocannon, or smaller). Also during Phase I, existing DOTC contractors will be prepared to support Phase II of the effort. Work on forming the fragmentation body with the pusher plate may start if DOTC work orders are prepared in time. PHASE II: During phase II, the contractor will fabricate warhead prototypes in accordance with government specifications. The government will load and perform static detonation testing to evaluate performance. The government will optimize designs for a full-up round. In parallel, the contractor will investigate forming the fragmentation body with the pusher plate. PHASE III DUAL USE APPLICATIONS: During Phase III, contractors will fabricate optimized warhead prototypes. The government will load and perform static detonation testing to confirm performance improvements. The government will then integrate the warheads into full up rounds for live fire testing. Work on forming the fragmentation body with the pusher plate may continue in this phase. A business study will be performed to evaluate the cost and performance enhancements of transitioning the technology. REFERENCES: An overview of the Metal Injection Moulding process; Powder Injection Molding International; https://www.pim-international.com/metal-injection-molding/an-overview-of-the-metal-injection-moulding-process/ A Mathematical Model of Penetration of Chunky Projectiles in a Gelatin Tissue Simulant, Larry M Sturdivan, ARCSL-TR-78055; https://apps.dtic.mil/sti/pdfs/ADA063525.pdf Metal Injection Molding of Tungsten Heavy Alloys: SBIR Phase I, Gary M Allen, MTL TR 91-37; https://apps.dtic.mil/sti/pdfs/ADA242742.pdf Enhanced Fragmentation Modeling, Peter Rottinger; https://apps.dtic.mil/sti/pdfs/ADA504428.pdf KEYWORDS: Tungsten, Fragment, Warhead, Medium Caliber, Metal Injection Molding, MIM