Researchers at TU Wien Develop Materials for Space Travel

"The higher the temperature in a material, the more the atoms move - and if the atoms move more, they need more space, the average distance between them increases," says Sergii Khmelevskyi from the Vienna Scientific Cluster (VSC) Research Center at TU Wien in a press release. Thermal expansion is inevitable, but can be almost balanced out by substances that produce a contrary effect.

TU Wien Researchers Create Computer Simulations of Atomic Level Behavior

Invar, an alloy of iron and nickel, for example, has a very low temperature expansion. It has long been known that the magnetic order in the material is responsible for this. Specifically, certain electrons change their state as the temperature rises. The material contracts because the magnetic order in the material decreases, which almost exactly cancels out the usual thermal expansion. Using computer simulations, a team led by Khmelevskyi analyzed the behavior at the atomic level and was thus able to understand the details of this process very precisely. Based on this work, published in the "Journal of Physical Chemistry C" in 2023, the scientists were also able to make predictions for other materials.

Pyrochlore Magnet Barely Expands with Heat

For a practical test, they worked with researchers from the Beijing University of Technology (China). The result was a so-called pyrochlore magnet, which consists of zirconium, niobium, iron, and cobalt. With this alloy, the length per degree over a temperature range of over 400 degrees changes by only about one ten-thousandth of a percent, according to the work accepted but not yet published in the Chinese professional journal "National Science Review". The reason for this is that some areas contain slightly more cobalt than others. According to the information, these subsystems react differently to temperature changes. This allows the material composition to be balanced out so that "a temperature expansion of almost exactly zero results overall".

(APA/Red)

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