Extraordinarily tough and strong materials are required to withstand high heat and radiation inside nuclear fusion reactors, such as the one seen here.
Drawing on inspiration from nature, researchers created tungsten heavy alloys that mimic the structure of nacre, also known as mother-of-pearl, in seashells.
Newswise — At the end of 2022, researchers at Lawrence Livermore National Laboratory announced they had observed a net energy gain through nuclear fusion for the very first time. This monumental milestone toward fusion energy represents a huge leap forward in powering our homes and businesses with the carbon-neutral energy source. But converting this scientific achievement into a practical power source also requires new technologies to make a fusion-powered society a reality. Scientists at Pacific Northwest National Laboratory (PNNL) and Virginia Polytechnic Institute and State University (Virginia Tech) are helping bring this goal to fruition through their materials research efforts. Their recent work, published in Scientific Reports, makes the case for tungsten heavy alloys and shows how they can be improved for use in advanced nuclear fusion reactors by mimicking the structure of seashells.
“This is the first study to observe these material interfaces at such small length scales,” said Jacob Haag, first author of the research paper. “In doing so we revealed some of the fundamental mechanisms which govern material toughness and durability.”
Withstanding the Heat
The sun—with a core temperature of around 27 million degrees Fahrenheit—is powered by nuclear fusion. Thus, it should come as no surprise that fusion reactions produce a lot of heat. Before scientists can harness fusion energy as a power source, they need to create advanced nuclear fusion reactors that can withstand high temperatures and irradiation conditions that come with fusion reactions.
Of all the elements on Earth, tungsten has one of the highest melting points. This makes it a particularly attractive material for use in fusion reactors. However, it can also be very brittle. Mixing tungsten with small amounts of other metals, such as nickel and iron, creates an alloy that is tougher than tungsten alone while retaining its high melting temperature.
It isn’t just their composition that gives these tungsten heavy alloys their properties—thermomechanical treatment of the material can alter properties like tensile strength and fracture toughness. A particular hot-rolling technique produced microstructures in tungsten heavy alloys that mimic the structure of nacre, also known as mother-of-pearl, in seashells. Nacre is known to exhibit extraordinary strength, in addition to its beautiful iridescent colors. The PNNL and Virginia Tech research teams investigated these nacre-mimicking tungsten heavy alloys for potential nuclear fusion applications.
“We wanted to understand why these materials exhibit nearly unprecedented mechanical properties in the field of metals and alloys,” said Haag.
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About PNNL
Pacific Northwest National Laboratory draws on its distinguishing strengths in chemistry, Earth sciences, biology and data science to advance scientific knowledge and address challenges in sustainable energy and national security. Founded in 1965, PNNL is operated by Battelle for the Department of Energy’s Office of Science, which is the single largest supporter of basic research in the physical sciences in the United States. DOE’s Office of Science is working to address some of the most pressing challenges of our time. For more information, visit https://energy.gov/science. For more information on PNNL, visit PNNL's News Center. Follow us on Twitter, Facebook, LinkedIn and Instagram.
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