Engineers in the U.S. have shown that graphene — a remarkable material that’s only 10 to 100 nanometers thick — could make for excellent body armor, absorbing 10 times the amount of energy than steel before failing.
The graphite making up pencil lead is made of atom-thick sheets known as graphene. This material is the strongest known yet, and is also flexible, transparent, and electrically and thermally conductive, qualities that have led scientists worldwide to investigate whether graphene could find use in advanced circuitry and other devices.
To learn more about graphene, scientists devised a miniature shooting ranges in which they fired glass microbullets at speeds of more than 6,700 mph, propelled by clouds of gold vaporized by lasers. They next used electron microscopy to analyze the effects of the ballistic tests on layers of graphene between 30 and 300 sheets thick.
“Graphene may be the strongest material, but it wasn’t clear if it was strong against high-speed impacts,” says study lead author Jae-Hwang Lee at the University of Massachusetts in Amherst.
The scientists discovered graphene possessed exceptional strength, allowing it to perform twice as well as Kevlar and absorb roughly 10 times the impacts that steel can. The carbon sheets dissipate energy by stretching into a cone shape at impact sites and then cracking in various directions.
Currently there is no way to make large sheets of graphene, so any armor based on graphene “will need to stitch together graphene flakes,” Lee says. He notes that graphene’s weakness is that it is very brittle, but armor using graphene might potentially orient sheets of the material along several directions to help it resist cracking.