Reactive materials are similar to insensitive high explosives, but are usually thermite-like pyrotechnic compositions of two or more nonexplosive solid materials, which stay inert and do not react with each other until subjected to a sufficiently strong mechanical, electrical or laser stimulus, after which they undergo fast burning or explosion with release of high amount of chemical energy in addition to their kinetic energy.
Fragments or projectiles made of such materials have therefore greater damaging effect than inert ones, with expected lethality increase up to 500%.
The mixtures under investigation include one or more finely powdered (down to nanoparticle size) metalloids or metals like aluminium, magnesium, zirconium, titanium, tungsten, tantalum, uranium[2] or hafnium, with one or more oxidizers like teflon or other fluoropolymer, pressed or sintered or bonded by other method to a compact, high-density mass.
To achieve a suitable reaction rate and insensitivity to impact, friction, and electrostatic discharge, fuel particles have sizes usually between 1-250 μm.
The RM weapons under development include an active protection system defensive grenade for intercepting incoming missiles or grenades and detonating them at a safe distance, and the BattleAxe warhead that covers a wide area with RM fragments with devastating results to soft targets, while the unexploded fragments left behind have very low lethality versus conventional cluster bomb remains.