A new composite material has been developed for use in fusion reactors.
“MISIS University is a recognized leader in materials science in Russia, ranked among the top 100 universities worldwide in the field of Materials Science according to the leading international QS ranking. Our researchers are engaged in developing technologies that find applications across various industries, including high-tech sectors. A team of researchers led by young scientist, PhD Stanislav Chernyshikhin, has developed a new composite material for use in domestically produced fusion reactors,” said Alevtina Chernikova, the rector of MISIS University.
Tungsten is considered one of the primary materials for plasma-facing components due to its high melting point and threshold energy for physical sputtering, as well as its low retention of hydrogen isotopes. However, it is challenging to machine mechanically due to its high hardness and brittleness. Typically, powder metallurgy methods are used to fabricate tungsten products, but traditional technologies do not allow for the creation of complex profiles.
As a result, the conventional design of plasma-facing components (PFC) consists of a simple multilayer structure. An alternative to traditional technologies is additive manufacturing, which enables layer-by-layer synthesis of products, including porous structures. The properties of such products can be tailored for specific tasks by varying the geometric structure features.
“Research and development of new methods for producing tungsten components have significant practical importance. Selective Laser Melting (SLM) technology is one of the most popular and widely used methods of additive manufacturing for metal products due to its ability to synthesize complex-shaped parts with high resolution. It is worth noting that producing tungsten products using the SLM method poses challenges due to the high melting temperature, the formation of non-fusion defects, microcracks, and overheating of various components in the equipment,” emphasized Stanislav Chernyshikhin, PhD, head of the laboratory at MISIS University.
By studying the conditions of laser synthesis of tungsten, the team at NITU MISIS managed to achieve a relative density of solid samples of 96.7 percent. Initially, skeletal structures of tungsten gyroids, resembling a curved mesh or wave, were created to form a bimetallic material. Copper was then infiltrated into the metal matrix at temperatures up to 1350°C with in situ monitoring of the process. Investigating the wetting and impregnation kinetics of tungsten matrices allowed for the establishment of optimal infiltration conditions.
Mechanical testing revealed that the composite exhibited significantly greater plasticity than pure tungsten—it could withstand deformation of up to 35 percent without failure. Furthermore, the university's scientists, in collaboration with AO “NIIEF,” conducted thermal conductivity measurements over a wide temperature range (up to 800°C). It was found that as the size of the elementary cell structure decreased, there was a slight reduction in thermal conductivity, while strength characteristics increased.
“In the future, we plan to move on to the production of prototypes of PFC and perform thermally loaded cyclic tests. The tests will simulate conditions close to real operational environments in fusion installations,” added Stanislav Chernyshikhin.
Detailed results have been published in the International Journal of Refractory Metals and Hard Materials (Q1).