When most
bombs go off, they release a spray of deadly shards of steel. Now, imagine that those shards were themselves explosive, detonating in a massive chain reaction. It''s for real: Defense contractors are harnessing the strange alchemy of
reactive materials (RMs) — in which two or more inert materials are mixed to create an explosion — to develop smaller, more lethal warheads, as well as new ways to protect troops against mortar rounds and rocket-propelled grenades.
RMs generally consist of powdered metals, such as aluminum or titanium, combined with an oxidizing agent. Whether that agent is another powdered metal or a nonmetallic compound, such as Teflon,
contact alone isn''t enough to trigger an explosion. A powerful
impact, however, will chemically mix the materials, igniting them and leading to a massive shock wave. "A big challenge is making
strong enough to survive launch, but fragile enough to react on impact," says Judah Goldwasser, program manager at the Office of Naval Research, which is developing RMs for potential use in antimissile systems. Instead of punching small holes in a target, Goldwasser says, RM shrapnel could cause an entire enemy missile to break up in midair.
Not surprisingly, RMs are also being developed for offensive purposes. The Air Force is working on a warhead called BattleAxe that will shower a large area with reactive fragments, devastating "soft" targets such as trucks. Cluster bombs often leave behind dangerous unexploded munitions, but stray RM fragments are safe to handle, which would help lower civilian casualties following military operations. Accidental drops won''t set RM fragments off, and they can be tossed in a fire to burn up