An Inch of Metal Foam Disintegrates Bullets

Bullet Shattering

Last week, North Carolina State University uploaded a video of a bullet being fired at a sheet of composite metal foam. Afsaneh Rabiei, a professor of mechanical and aerospace engineering at NC State, has spent years developing composite metal foams, and the fruits of her labors are clear to see as the armor piercing round completely shatters after impacting the metal foam.

The bullet used in the demonstration video is a 7.62 x 63 millimeter M2 armor-piercing projectile, and was fired using standard testing procedures established by the Department of Justice for evaluating armor types.

The composite metal foam (CMF) that disintegrates the bullet was created by combining several bullet stopping materials into one single piece of armor. CFMs  are formed from hollow beads of one metal within a solid matrix of another, such as steel within aluminum. The result is a both lighter-weight and stronger form of protection.

“We could stop the bullet at a total thickness of less than an inch, while the indentation on the back was less than 8 millimeters,” Rabiei said of the CFM. The US National Institute of Justice (NIJ) has a standard of 44 mm required to stop an armor piercing round, and this is the standard used by Kevlar, the most well known bulletproof vest manufacturer. To compare the CFM only has a thickness of 25 mm.

But don’t think that this development is only useful for defense. Rabiei hopes to use it to stop more than just bullets. Earlier testing has shown that CMFs can withstand extremely high temperatures and are able to block x-ray, gamma-ray, and neutron radiation.

For now though, it may “only” be used as the world’s most lightweight and effective armor ever, but who know what advances researchers like Rabiei will be able to make with this material going forward. CMFs has the potential to be used in nuclear transportation, satellite shielding, or even in something as comparatively mundane as making safer cars.