Test & Measurement

Lightweight, Composite Metal Foam Stops Bullet

Vehicle designers may soon be able to develop lighter military vehicles without sacrificing safety, thanks to research from North Carolina State University . The researchers demonstrated that vehicle armor using composite metal foam (CMF) can stop armor-piercing, .50 caliber rounds – even though it weighs less than half as much. CMF is a foam that consists of hollow, metallic spheres embedded in a matrix of metallic alloys. In the NC State study, the researchers used steel-steel CMF; both the spheres and the matrix were made of steel. For the study, the researchers manufactured a hard armor system consisting of a ceramic faceplate, a CMF core, and a thin back plate made of aluminum. The armor was tested using .50 caliber ball and armor-piercing rounds, and was able to absorb 72-75% of the kinetic energy of the ball rounds and 68-78% of the kinetic energy of the armor-piercing rounds.