In what sounds like news straight from a Marvel comic book, materials scientists have created a shape-shifting metal alloy that can handle being blasted with heat and then cooled thousands of times. Afterward, the metal reverts to its original state.
Scientists have known about a special form of metals with a crystalline structure called martensite for a while now. These martensitic metals are made by combining several metals into an alloy that can be crumpled or bent and still return to a previous shape. Sounds magical, right? The drawback is that they tend to be like a wind-up toy with a dying battery. After a bit of deformation, they can degrade to the point of uselessness.
A team from the University of Minnesota’s Aerospace Engineering and Mechanics department might have toughened the metal up. They’ve created a new martensitic metal alloy using specific proportions of zinc, gold and copper — and their version degrades very little after more than 16,000 thermal cycles, according to a letter they published in the journal Nature (abstract).
The new metal alloy could have all kinds of applications, according to the team led by professor Richard D. James and postdoctoral research associate Yintao Song. ”You could make devices that convert heat to electricity directly,” James told the BBC’s Simon Redfern. “They could use the waste heat from computers and cell phones to recharge the battery and make them more efficient.”
Beyond such energy-harvesting devices, other potential applications include automatic sun-facing technology for space, super-efficient refrigerators, quieter jet engines as well as improved sensors for cars and medical devices.
The shape-memory alloy was praised as a great advancement for the field in a Nature commentary by Toshihiro Omori and Ryosuke Kainuma from the Graduate School of Engineering at Tohoku University. They pointed out that challenges remain, however. Given its pricey components, the alloy would be expensive and difficult to manufacture on a large scale, which limits its practicality.
“Nonetheless, by providing clear direction for the design of reliable shape-memory alloys, Song and co-workers’ findings will create quite a stir in the field of materials science,” Omori and Kainuma wrote. Maybe someone should notify S.H.I.E.L.D. Well, nobody can because that’s just a fictitious agency. For now.
Image: The University of Minnesota martensite between transformations. Credit: Richard D. James (video)