The super-steel for next gen body armour


New crystalline material is strong enough for any superhero. Viviane Richter reports.


An officer in the US Army's 172nd Brigade Combat Team dons his body armour before a patrol in 2009 in Musayyib, Iraq. – Chris Hondros/Getty Images News

If you were dazzled by Batman’s new armour in Dawn of Justice, or must have the slick suit Marvel’s Daredevil sports, then you are in luck – next-generation armour is on its way in real life.

A team of US scientists, funded by the US Defense Threat Reduction Agency, have just created a steel alloy of record-breaking strength.

The material which they call “SAM2X5-630” has the highest recorded elastic limit – the threshold to withstand impact without permanently deforming – of any steel alloy, the scientists say. They hope it will find use in body armour for soldiers or meteor-resistant hulls for satellites.

The method for forging SAM2X5-630, a process called “spark plasma sintering”, sounds a little science fiction itself.

The team mixed metal powders in a graphite mould, pressurised them at 1,000 atmospheres under a current of 10,000 amps, all at a blistering 630 °C.

This process creates small crystal regions throughout the metal in which the iron atoms take on a different arrangement to those in an average steel structure.

These crystal regions, the researchers believe, are the key to the material’s strength.

Alloy could in future be used for satellite casings which deflect high-speed meteorites.

At a thickness of around two credit cards, SAM2X5-630 withstood being crushed at up to 12.5 gigapascals, or 125,000 atmospheres, without deforming. That’s over double the strength of tungsten carbide – a high-strength ceramic used in military armour, which has an elastic limit of 4.5 gigapascals.

The team also found their alloy did not permanently deform after being pelted with copper plates fired through a gas gun at up to 1,300 metres per second – one and a half times faster than the muzzle velocity of an M4 assault rifle.

“The fact that the new materials performed so well under shock loading was very encouraging and should lead to plenty of future research opportunities,” said author Veronica Eliasson from the University of Southern California.

One benefit over other methods for creating alloys, the authors say, is that spark plasma sintering happens in a mere flash.

“You can produce materials that normally take hours in an industrial setting in just a few minutes,” said study author Olivia Graeve, from the University of California, San Diego.

She says the technique allows for enormous time and energy savings.

The researchers believe the alloy could in future be used for satellite casings which deflect high-speed meteorites, bullet-proof body armour, or every-day applications such as stronger bits for drills.

Of course we’re all waiting for it to be picked up by the next New York superhero.

The material’s fabrication and testing was published in Scientific Reports.

Vivian ritchter 2016.jpg?ixlib=rails 2.1
Viviane Richter is a freelance science writer based in Melbourne.
  1. http://www.nature.com/articles/srep22568
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