Programs Reviewed
Reactive Materials1
Findings

The concept is to develop energetic penetrating materials that exploit the synergy between the properties of the ordnance and those of the target to maximize damage to the target. The lethality of warheads is enhanced by a combination of kinetic and chemical energy released by reactive fragments when the target is hit. The cumulative effect of various damage mechanisms can increase the probability of target kill. Integrating the energetic penetrating materials in the structure of the warhead and optimizing the packaging and delivery options can also improve effectiveness.

However, current mathematical models and materials characterization do not yet allow quantitative predictions that would be useful for the design of the ordnance. Also an open question is how easily a target could be modified and protected from such optimized adaptive ordnance.

Work in reactive materials has two parts. The first includes development of more energetic explosives and the use of reactive materials as fragments to be applied explosively to the target in addition to the energy released within the target by the warhead bursting charge. The briefing indicates that projected advances are being regularly validated through experimental work, which appears to be well organized and productive. The reactive materials are of several compositions. The current baseline composition is aluminum (Al) powder suspended in a perfluoro polymer (PTFE or a similar derivative). When a conventional explosive propels a reactive fragment of Al/PTFE into a target, the fluorine in the PTFE reacts violently with the Al. As the Al/PTFE passes through the wall of a target, it reacts with oxygen in the air to produce an explosion within the target, causing much more damage.

Other energetic material compositions include thermitic material such as Al+MoO3 with a PTFE binder. This material is also known as a metastable intermolecular composite. The fluorine serves to initiate the reactivity of the Al. There are other fuel plus oxidizer thermitic materials that can advance this technology.

The second part of the work is the development of honeycomb warhead structures into which the explosive material can be infused. While somewhat less advanced, the work appears to be sound. There are several approaches to enhancing the energy of the warhead. These include new energetic molecules, the use of finely divided (nanosize) metal powder (e.g., aluminum or hydrides such as aluminum hydride), new metastable states, and sol-gel techniques for encapsulating these materials. Nano laminate materials also offer the possibility of hard energetic cases that will withstand penetration at high velocity and contribute energy when detonated via intermetallic reactions. The work is well coupled with the national effort in energetic material —the National Energetic Material Program and the Joint DOD/DOE Office of Munitions memorandum of understanding.

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As presented to the committee, this D&I thrust encapsulates Code 351's weapons-related efforts in the Missile Defense Future Naval Capability (MD FNC). The objectives of the MD FNC are as follows: (1) respond to the Joint Requirements Oversight Council (JROC)-approved Joint Theater Air and Missile Defense mission need statement and capstone requirements document and (2) demonstrate emerging and maturing technologies that span the full spectrum of theater air and missile defense. See <www.onr.navy.mil> for additional details.



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