Pacific Northwest National Laboratory Researchers have joined forces with counterparts at Virginia Polytechnic Institute and State University to better understand how to produce and harness useable energy through nuclear fusion utilising tungsten-based ferroalloys.
The scientific coalition have published a recent paper in the Journal Scientific Reports, where researchers outlined the need for improved tungsten-based ferroalloys for use in nuclear reactors.
Researcher and one of the authors of the paper, Jacob Haag explained that it was critical for fusion reactors to be able to withstand immense temperatures before harnessing the reactions was possible.
Tungsten is an element with an exceptionally high melting point, rendering this material an attractive option for reactor manufacturers however the element comes with its own challenges. Unfortunately, tungsten on its own, although incredibly heat resistant, is also extremely brittle. By combining it with other metals like nickel and iron, a more flexible and durable ferroalloy can be designed and utilised in shielding reactors from the immense heat.
Haag and the paper’s other authors have also demonstrated that it isn’t just the material’s composition that will be key in a next-gen reactor heat-resistant shielding. The structure of a new tungsten-based ferroalloy would also be key in its nuclear usefulness with the research group looking to the structure of seashells as their inspiration.
They discovered a specific new hot-rolling technique for the tungsten ferroalloy, where a series of microstructures can be created in the material to mimic the structure of nacre or mother-of-pearl. Nacre commonly found in seashells is also known to encompass extraordinary durability and strength.
In the same way as nacre, the heavy alloy required for fusion heat shielding will consist of two different segments including a hardened segment made of almost pure tungsten and a ‘ductile’ segment containing a more balanced mixture of nickel, tungsten and iron with the group’s research implying that the strength of this ferroalloy comes from the effective bonding of these two material components.
Haag said that this study was the first to observe such alloy materials and their interfaces at such a small scale.
“We wanted to understand why these materials exhibit nearly unprecedented mechanical properties in the field of metals and alloys, he said.
“In doing so we revealed some of the fundamental mechanisms which govern material toughness and durability.”
The research shows how crystal structure, geometry, and chemistry all contribute to the formation of strong material interfaces in tungsten-based ferroalloys. It also exposes techniques that can be used to improve material design and attributes for fusion applications.
Learn about Tungsten alloys.
