A cellular metallic structure, usually of aluminum or zinc alloys, made by incorporating titanium or zirconium hydride in the base metal. This subsequently evolves hydrogen to produce a uniform, foamlike material. Its density is approximately that of seawater so that it is weightless when submerged. The principal use of foamed metals is in absorption of shock impact without elastic rebound. Fiber-reinforced light-metal foams have potential application in reducing the weight of automobile bodies.