The "transformation" of Nitinol into an ultra-strong elastic material promises to create deformable wings

Shape-shifting aircraft remain a science fiction concept, as scientists have struggled to develop a material that is both flexible and strong enough to withstand flight conditions.

Researchers at the National Institute of Materials Science (NIMS) in Japan have developed a nickel-titanium alloy ultra-strong elastic material. The material is as strong as steel but 20 times more malleable, and can even stretch like rubber to make deformable wings. The results of the study have been published in the current issue of Nature (DOI:10.1038/s41586-024-07900-4).

▲ Comparison of DS-STG alloy with typical metal alloys and organic materials

Previous research has determined that titanium-nickel alloys have some special properties, such as being able to stretch to limits far higher than other metal alloys while keeping their shape unchanged; When the temperature of the alloy is increased, it can return to its original shape, the problem is that this property is very temperature limited.

▲ DS-STG alloys exhibit polymer-like ultra-high strength and excellent resistance to high strain fatigue over a wide temperature range

In response, NIMS Professor Ren Xiao's team designed a "three-step procedure" that allows the nickel-titanium alloy to exhibit this property over a wider temperature range.

First, the researchers deformed the alloy and stretched it by more than 50%, then heated it to 300 ° C, and then repeated it again, with a third time stretching the alloy by 12%. By the end of the process, the material was able to withstand pressures 18,000 times higher than normal atmospheric pressure, was strong enough to be comparable to steel, and was 20 times more flexible than commonly used alloys.

▲ Realize the three-step thermal machining route of DS-STG alloy and the microstructure of the sample after each step

So far, the researchers have succeeded in making this titanium-nickel alloy exhibit this property over a wide range of -80 ° C to 80 ° C.

Ren Xiaobing told NewScientist that the alloy exhibits these properties because it behaves more like glass than metal. According to reports, the alloy has parts of the molecules arranged in a way that allows it to support the material to complete deformation rather than fracture, and glass has no such regions, so it is very brittle.

It is worth mentioning that because the method of developing this material is very simple, we can completely repeat its operation process and results in other laboratories, and this material is also suitable for large-scale industrial manufacturing, I believe there will be further research in the future.