Metallic glass is stronger and tougher than steel (video)
Recently, I went with the SmartPlanet video crew to check out Robert Ritchie's lab at the University of California at Berkeley. Inside his small office, I tried bending one of the materials. One bent and easily bent back, which is unusual for a metal. Normally, when you bend a metal, it stays in that shape and it's hard to bend it back.
Ritchie has created metallic glass, a material he believes is the strongest and toughest to date. During our visit, Ritchie brought us to the bottom basement of the old engineering building to show us how he and his students try to break the new material to see if it's resistant to fracture. In the future, Ritchie hopes metallic glass could one day be used for airplane engines and large structures such as bridges.
In case you missed it, I previously wrote about Ritchie's new metallic glass:
Ritchie said “trying to get high strength and high toughness is very difficult. One of the holy grails is to get both high strength and high toughness [in materials]. We call that damage tolerance.”
To make this metallic glass, the researchers used five elements to confuse the material. That way, the material couldn’t flex into automatic memory and form its normal, crystal structure.
This is unusual, considering all metals have crystalline structures. Window panes are amorphous and aren’t crystalline in structure.
Like glass, the fabricated material was not crystalline.
“We learned to make metals in this amorphous state,” Ritchie said. “There are stronger materials and there may be tougher materials, we know of no other material with the combination [we've made]. Strength and toughness are mutually exclusive, and we’ve achieved it in a material that you wouldn’t expect - in glass. Glass is usually brittle,” Ritchie said.
The group from Cal Tech made the material from five or more elements. They melted it and it cooled quickly. The material wasn’t able to crystallize, so it formed an amorphous material. The Cal Tech team cut the material into little rods and sent them to Ritchie’s team at Berkeley to basically destroy the metallic glass.
The experiments didn’t involve throwing the metallic glass against the floor though. Instead, Ritchie ran the metallic glass through mechanical testing machines. The machines could barely make the material crack.
In the future, the new material could be used in nuclear pressure vessels because it has the same toughness as the material used today. A better material could help nuclear reactors avoid a catastrophic failure.
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This post was originally published on Smartplanet.com