Science (2020). DOI: 10.1126 / science.abc1590 “width =” 800 “height =” 480 “/>A team of researchers at Tohoku University has developed a new type of superelastic alloy with an almost limitless superelastic window. In her paper published in the journal Science, the group describes the properties of the new alloy and possible uses for it. Paulo La Roca and Marcos Sade with Universidad Nacional de Cuyo – CNEA have published a Perspective piece in the same journal issue outlining the state of flexible alloys and the work done by the team in Japan.
Most metals in daily use can bend slightly. To get them back to their original shape generally requires force such as that of a hammer. Superelastic alloys (also called metals with shape memory) can be bent with a maximum of 20 percent deformations and will automatically return to their original shape. La Roca and Sade note that superelasticity in metals can be explained by the presence of stress-induced martensitic transformations. But there is a caveat to such alloys – they can only return to their original shape when they are in a certain temperature range: their superelastic window.
Unfortunately, most such windows are quite small, which limits the use of superelastic metals in practical applications. Scientists want to discover alloys that can be used in wider temperature variants for use in applications such as space science (because of the extreme temperatures). In this new attempt, the researchers found just such an alloy – one with an almost limitless superelastic window. During testing, the superelastic window was found to be 10 to 473 K (-263 ° C to 200 ° C), making it applicable in virtually all natural settings. The researchers note that the alloy also found a very low thermal expansion.
The team made the alloy by adding chromium to a Fe-Mn-Al-Ni alloy. In addition, they also showed that entropy change is controllable with this approach. The entropy change for the new alloy was tested to be very close to zero. The researchers also note that the alloy is tunable by changing the amount of chromium, which highlights the fact that the team actually created a host of superelastic “invar” alloys.
New lightweight shape-shifting alloy shows potential for a variety of applications
J. Xia et al. “Iron-based superelastic alloys with almost constant critical stress temperature dependence,” Science (2020). science.sciencemag.org/cgi/doi… 1126 / science.abc1590
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Citation: A Superelastic Alloy with an Almost Limitless Temperature Window (2020, August 14th) Retrieved August 14, 2020 from https://phys.org/news/2020-08-superelastic-alloy-limitless-temperature-window.html
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