The wispy metal strip in my hands is 8 inches long, 1 inch wide, and as thin as aluminum foil.
“Try to tear it,” says William Johnson, a materials science professor at Caltech in Pasadena.
I pull—first gently, but soon with all my might. No go.
“See if you can cut this,” suggests Johnson’s postgraduate assistant Jason Kang, handing me a mirror-bright piece of the same metal. It’s an inch long, a quarter inch wide, and thinner than a dime. I bear down with a heavy-duty pair of wire cutters. The metal will not cut. I try again, squeezing with both hands until my fingers ache. Nothing.
But the most amazing act in this show is yet to come.
“Watch,” says Johnson. From a height of about two feet, he drops a steel ball onto a brick-size chunk of the metal. The ball bounces so high and for so long—1 minute and 17 seconds, with a metronomic tick, tick, tick—that it looks unreal, like some kind of cinematic special effect. “When you try that with regular steel, it goes ‘clunk, clunk, clunk’ and stops,” says Johnson. If the metal were glued to an unyielding surface such as concrete (instead of sitting on Johnson’s oak coffee table, which absorbs a lot of the energy), “the ball would bounce for more than two minutes,” he says. “I’ve done it.”
It’s all astounding, yet oddly familiar. In the typical science fiction film circa 1950, there’s that scene in which scientists return from the just-landed flying saucer and tell the Army brass that no tool known to humankind can cut, burn, bend, or otherwise scar the hull. But the metal in front of me is decidedly terrestrial in origin—it was developed in Pasadena, specifically in the lab down the hall from Johnson’s office.
It is called metallic glass, or amorphous metal, and it appears to be nothing less than an entirely new class of material that can be used to build lighter, stronger versions of anything. “Everything from an Abrams tank to an F-16 jet to a bicycle can be made out of this, and because it is two to three times the strength of conventional alloys, you can halve the weight or more. That’s not evolutionary, it’s revolutionary,” says Johnson. “This is the structural material of the future.”
Strength is not its only virtue. It can also be formed like a plastic. So instead of laboriously making sheet metal and then cutting, machining, and drilling, say, a car fender, all of which weakens the part, a glassy metal fender could be injection-molded in one piece—a breakthrough. “The idea that you can cast something like a plastic part with very high strength is a completely new development,” says materials science professor William Nix of Stanford University, an adviser to Liquidmetal Technologies, which is trying to commercialize the metal.
Better yet, it can be readily made into a foam. “With most metals that’s difficult, because the bubbles want to rise to the surface of the molten metal,” says Johnson. The fact that amorphous metal is thick and like plastic when molten permits the formation of a foam panel that is 99 percent air but roughly 100 times stronger than polystyrene. A sandwich made of two thin sheets of amorphous metal flanking amorphous foam would be strong, light, insulating, fireproof, bug-proof, rustproof, sound dampening, and difficult to penetrate with bombs. Such panels could form buildings, ship hulls, airplanes, and car bodies.
“Glassy metals will be a cut above both metals and plastics,” says Kang, looking up from a plasma arc melter in which he forges new formulations. Asked if his aim is to replace both—which covers a lot of territory—he smiles. “That’s what we’re shooting for,” he says.
But metallic glass has one huge problem—it’s expensive. The first commercialized injection-moldable form costs about $15 a pound to make versus roughly $1 a pound for aluminum and 25 cents a pound for steel. Johnson, Kang, and other researchers are working on variants with cheaper constituents. “I think we can make a viable amorphous steel product. I would call that a very likely development,” says Johnson. Eventually, he says, it could cost the same 25 cents a pound as ordinary steel. “That will change everything,” he says.
Still, fundamental shifts in basic materials don’t happen overnight. Even if bulk metallic glasses become cheap, the world’s metalworking factories will need to be completely retooled to accommodate them. Ted Hartwig, a mechanical engineering professor at Texas A & M University, who has been working on a U.S. Army project to develop large-bore amorphous-alloy ammunition, counsels patience. “Remember when everyone was predicting back in the 1970s that we’d have ceramic engines? Where are they?”