Brain Fertilizer

...they announce stuff like this:

Reactive Materials (RMs) generally consist of powdered metals, such as aluminum or titanium, combined with an oxidizing agent.

..."A big challenge is making [RMs] 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.

...Part of the Army's Active Protection System program, the warhead will detonate threats at a safe distance, while possibly limiting the risk of friendly fire. (Unlike steel shrapnel, RM shards can be made to burn out quickly.)

...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.