The hottest research on silicon carbide for nuclea

2022-08-11
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Ningbo Institute of materials published comments on the research of silicon carbide for nuclear use and the genome engineering of nuclear materials

Abstract: Recently, researchers from the nuclear materials engineering laboratory (Preparatory) of Ningbo Institute of materials technology and engineering, Chinese Academy of Sciences were invited to publish comments on the journal scripta materialia in the field of materials, and analyzed the key problems existing in the nuclear use of silicon carbide fiber reinforced silicon carbide composites, And the role of material genome technology in the research and development process of nuclear materials

nuclear power is mainly the development and safety improvement of fixture materials that customers do not understand clearly when choosing, which is inseparable from the emergence of new nuclear materials and the improvement of traditional nuclear materials. Since the Fukushima nuclear accident in 2011, people have put forward an urgent need for accident tolerance of reactor cladding materials, that is, in a period of time after the nuclear safety accident, the cladding materials can maintain the integrity of its structure and function, so as to buy time for subsequent rescue and repair work. Recently, researchers from the nuclear materials engineering laboratory (Preparatory) of Ningbo Institute of materials technology and engineering, Chinese Academy of Sciences were invited to publish comments on scripta materialia, a journal in the field of materials, and analyzed the key problems existing in the nuclear application of silicon carbide fiber reinforced silicon carbide composites, as well as the role of material genome technology in the development of nuclear materials

the new type of accident tolerant nuclear fuel (ATF) cladding material requires it to further improve its oxidation resistance in high-temperature water vapor environment and its ability to accommodate fission gases on the basis of its original mechanical properties, radiation resistance and corrosion resistance. Silicon carbide fiber reinforced silicon carbide ceramic matrix composite (sicf/sic) has the characteristics of high strength, high temperature resistance, corrosion resistance, radiation resistance and so on. It is considered to be one of the best candidate nuclear materials for accident tolerant nuclear fuel cladding, structural components facing high temperature irradiation environment, spallation target structural units, nuclear fusion reactor flow channel inserts and other components. At present, the biggest problem of nuclear sicf/sic composites under neutron irradiation environment is the intermediate layer between fiber and matrix. Due to the different crystallinity between the fiber and the matrix and the limitation of the radiation resistance of the interlayer interface, low-dose neutron irradiation will cause a large number of microcracks in the composite, which will directly lead to the decline of mechanical properties and thermal conductivity after irradiation. Viewpoint review the traditional interface layer materials such as pyrolytic carbon (PyC) and hexagonal boron nitride (BN) are analyzed in detail. If they have poor radiation resistance or are neutron poisons, they are easy to be oxidized, which leads to the insufficient service stability of the composites in the irradiation and oxidation environment. Comments on the selection of ternary layered ceramic Max phase material as interlayer for the first time. Max phase material has the characteristics of both metal and ceramic, excellent radiation resistance, oxidation resistance and fracture energy absorption, and can be used as a new fiber toughened ceramic matrix composite interface layer. However, due to the high preparation difficulty of these materials, there is no relevant report on the preparation of Max phase interface layer on the fiber surface at home and abroad. In the past, the nuclear materials engineering laboratory (Preparatory) of Ningbo Institute of materials introduced a recently developed preparation process of Max phase coating on the surface of fibers based on in-situ reaction with high temperature ionic liquid as the medium. For the first time, a uniform and thickness controllable Max phase coating was prepared on the surface of carbon fibers and silicon carbide fibers. There is a thin polycrystalline tic transition layer inside the coating and a max phase Ti2AlC layer outside. By changing the reaction conditions, the coating thickness and surface morphology can be effectively controlled. The results show that the coating can provide effective antioxidant protection for carbon fiber and silicon carbide fiber under the conditions of high temperature air oxidation and water vapor oxidation. Once published, this work attracted wide interest from international peers. Takaaki koyanaki, a researcher of nuclear fusion materials at Oak Ridge National Laboratory in the United States, made a special introduction to this work at the 18th International Conference on nuclear fusion materials

in view of the urgent demand of the nuclear energy industry for new ATF cladding materials and the shortening of the R & D cycle of such materials, the theoretical research team of the nuclear energy materials engineering laboratory (Preparatory) of Ningbo Institute of materials proposed to enable Zeng to open the conversation and optimize the design of ATF cladding materials with the material genome method. In this design strategy, aiming at the difficulty of predicting the macro performance of materials from their microstructure, researchers established a multi-scale coupling calculation scheme centered on the parameter transfer between the algorithms of various scales by capturing the research focus of theoretical models at different scales (see Figure 2). During the implementation of this scheme, researchers first studied the mechanical and energy parameters of single crystal materials on the nano scale by using the first principles method, and the calculation results were also used to fit the potential field used in molecular dynamics. At the micro scale, molecular dynamics is used to calculate the distribution, movement behavior and influence of micro defects in the material, and the results are transferred to phase field and finite element calculation. On the mesoscopic scale, the phase field method combined with the theoretical model of crystal plasticity is used to simulate the grain evolution process during cold rolling and hot processing, and find out the influence of processing parameters on the microstructure such as grain graduation. On the macro scale, the macro mechanical and thermal properties of polycrystalline materials are predicted by finite element simulation. On the occasion of the 81 military day, the key points such as stress-strain curve, temperature field and stress field distribution are finally obtained. 2 Adjust the engineering parameters of machine conditions according to the size of all finished products that are too large or too small. The whole calculation scheme solves the coupling problem of theoretical calculation at different scales by transferring data from low scale to high scale, and realizes the effective prediction of macro thermodynamic properties by using material genome method

the above opinion review article was published in the special issue of scripta materialia specially invited nuclear energy materials

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