Scientists have created an alloy with a long memory, but it won't help you in a spelling bee. Its long memory is solely for returning to its original shape, no matter how much you bend and twist it.

This new alloy, made from the metal elements nickel, titanium and copper, has a property known as "ultra-low fatigue." This means that the alloy can do millions of 'reps' without losing its original shape. The alloy, once bent, stays in that form until it is 'prompted' back to its initial form using heat.

"Usually shape memory alloys—like in minimally invasive surgery—they regain their shape once, or a few times, but not multiple times," explained Professor Manfred Wuttig of the University of Maryland, one of the new paper's senior authors.

This remarkable property is thanks to the atomic configuration of the nickel, titanium and copper atoms that can arrange themselves in two different ways, and can switch between them over and over and over again. This is what makes this new alloy superior to previous memory alloys that tend to lose their spring-back ability after extensive use.

Wuttig has put the alloy through 10 million cycles of being bent and returned to normal—a number that is quite a lot for a human to do. Fortunately, there was a solution.

"With stress it's not so difficult. You can buy [or build] little stress-strain machines... So you can automate that and then it's not so difficult. But it takes in the order of weeks to generate the number of cycles. It's much more difficult with temperature." In order to heat and cool the metal 10 million times they used a specialized furnace. "It took a few weeks to conduct the experiment," Wuttig said.

There are plenty of creative uses for this bendy alloy. Suggestions include the use of the alloy in airplane wings, unfolding solar panels on a spacecraft, or even as a hardworking artificial heart valve.

"Your refrigerator has a compressor. It compresses and expands a liquid that goes through phase transition," Wuttig explained. "So instead of that liquid, you could use this alloy."

A similar, nickel titanium alloy (not the one featured in this article) returning to its original shape when heated.

[Via Science]