An aluminium alloy that is 100 times more resistant to radiation damage than a common spacecraft material could be used to improve shielding in crew capsules or build houses on Mars.
Aluminium alloys are often used in space because they are both lightweight and strong. But when they are exposed to powerful radiation from the sun or galactic rays for long periods of time, their molecular structure can change, making them weaker or more brittle.
In 2019, at the University of Leoben in Austria and his colleagues created a new alloy by mixing an aluminium and magnesium alloy with zinc and copper and crushing it at extremely high pressures. The resulting hardened structure, which was very tightly packed with atoms, had unusual properties, such as keeping its structure and hardness after being exposed to high levels of radiation. But it also became brittle, which rendered it useless for space applications.
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Now, Pogatscher and his team have modified their alloy by heating it to more than 200掳C (392掳F). This caused the grains that make up the alloy to be nanometre-sized, rather than micrometre-sized, which helped it keep its flexibility and strength after irradiation. 鈥淲e have solved this problem in a way that [means] the material doesn鈥檛 embrittle, and also the phase is still stable up to very high irradiation limits,鈥� says Pogatscher.
The researchers used an electron microscope to examine the effect of bombarding the material with different doses of energetic heavy ions. They found that the alloy was 100 times more resistant to doses of radiation than an alloy of aluminium called 6061, which is widely used in spacecraft.
This would make the material well suited for spacecraft that have to spend very long periods under constant irradiation. It could extend the life of missions like the James Webb Space Telescope and deep-space probes. The material could also be used to contain miniaturised nuclear reactors on spacecraft, or in habitable structures on the moon or Mars, says Pogatscher.
While they didn鈥檛 test how well the material would block radiation for astronauts, structural features indicate that it might be better than currently used materials, he says.
鈥淔or lightweight alloys, for space applications, this is a highly significant step forward in terms of radiation resistance,鈥� says at the University of Sheffield, UK. The materials used in the alloy are cheap and widely available, but it still needs to be proven that the alloy can be produced using this method at scale, he says.
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