When you look at the gadgets that surround you, chances are, they’re made of aluminum. There’s a reason for that. Steel might be great for everything from skyscrapers to cookware because of its strength and cheapness, but it’s heavy. Then there’s titanium. It’s a gorgeous metal that is light, strong, and both crack and fatigue resistant. It’s perfect for everything from jet engines to laptops. But as Boing Boing points out, it’s also expensive: compared to steel, which costs $0.30 a pound, or aluminum, which costs $0.84 a pound, titanium costs almost three dollars per pound
This week, though, a team of material scientists at Pohang University of Science and Technology led by researcher Hansoo Kim have announced a major breakthrough. They’ve discovered a new type of flexible, ultra-strong steel that has the same strength-to-weight ratio as titanium alloys, but at just a tenth the cost.
Back in the 1970’s, Soviet scientists discovered that you could mix aluminum and steel together to make an incredibly strong but lightweight alloy, but it was brittle. Push it too far, and the metal would break like ice, not bend. The issue was a sort of metallic crystallization: when forming the aluminum-steel alloy, atoms of aluminum and iron called B2 crystals would fuse together in brittle, subatomic veins, according to Popular Mechanics.
What Kim realized was the key to making a stronger steel-aluminum alloy lay in the B2 crystals. If he could more evenly disperse them so they did not bond to one another, then the crystals would not form into brittle veins. Kim and his team discovered that by adding a small amount of nickel to the alloy, then heat-treating and thinly rolling their steel, they could precisely control where the B2 crystals form. The result is an alloy that is 13% less dense than normal steel, but has the same strength as titanium.
So will your next iPhone be made of steel? Not so fast. Although Kim’s process works in the lab, there’s a major hurdle to face before you’ll see this in the real world. Mass-produced steel is usually protected from the elements with a silicate layer, which can’t be used on Kim’s process: a different way to protect this new steel-alloy will need to be ironed out in the real world. But when that’s discovered, watch out: everything from tomorrow’s skyscrapers to the iPhones of the future could end up being made of super steel, although the researchers seem to think this technology will be mostly of interest to automotive and aerospace companies.
The study was published in the February 5th issue of Nature.
[via Popular Mechanics]