Study of Helium Swelling and Embrittlement Mechanisms in SiC Ceramics

Abstract

This work is devoted to the study of the radiation damage kinetics and subsequent embrittlement of the near-surface layer of SiC ceramics subjected to irradiation with low-energy He2+ ions. Interest in these types of ceramics is due to their great prospects for use as structural materials for nuclear power, as well as for use in the creation of protective structures for long-term storage of spent nuclear fuel. During the study, the dependences of changes in the structural, mechanical, strength, and morphological characteristics of SiC ceramics depending on irradiation fluence were obtained. It has been established that the greatest changes in the strength properties are associated with the dominance of the crystal lattice swelling effect in the structure due to an increase in the concentration of implanted helium, and its further agglomeration with the formation of vacancy complexes of the He-V type. A model for changing the structural properties of ceramics irradiated with low-energy He2+ ions based on the change in the contributions of the dislocation density concentration, anisotropic distortion of the crystal lattice, and the effect of swelling as a result of implantation is proposed.

Study of Structural and Strength Changes in Lithium-Containing Ceramics—Potential Blanket Materials for Nuclear Power, Subjected to High-Dose Proton Irradiation

“…The general trend in the change in the Li2TiO3 ceramic crystal lattice volume depending on the irradiation fluence corresponds to the observed effects of crystal lattice deformation and is because of swelling and subsequent destruction at high irradiation fluences. The trend of change in the crystal lattice volume can be divided into It can be seen from the presented data that the main differences in the crystal lattice deformation and an increase in the anisotropic nature of the crystal lattice deformation were previously found for SiC ceramics subjected to irradiation with helium ions [31]. In this case, the anisotropic deformation of the crystal lattice of SiC was explained by the authors by the hexagonal type of structure, as well as the difference in chemical and crystalline bonds of the Si-C, Si-Si, C-C type, the partial destruction of which can lead to the crystal lattice destruction at high irradiation fluences, and the accumulation of implanted hydrogen, followed by the formation of gas-filled bubbles.…”

Fabrication and Process Optimization of Chinese Fir-Derived SiC Ceramic with High-Performance Friction Properties

“…Direct carbonization of monolithic Si [ 22 ] and thermal reduction of SiO 2 [ 23 ] by carbon are considered more desirable methods of producing SiC materials due to their low cost, ease of process, and high productivity [ 24 ]. However, chemical vapor deposition of SiC via precursors of SiH 4 and small hydrocarbon molecules (e.g., C 2 H 4 , C 3 H 8 ) diluted in a hydrogen carrier gas, processed at 1500~1600 °C, is limited due to the need for higher temperatures (up to 2700 °C) due to the low diffusion coefficient of the strong covalent Si–C bonding, the small contact area between reactants, and the low efficiency of heat transfer [ 25 , 26 ].…”

Study of Radiation Resistance to Helium Swelling of Li2ZrO3/LiO and Li2ZrO3 Ceramics

“…The problem of helium accumulation in the structure of the near-surface layer and subsequent destruction processes has become quite acute in recent years among studies due to the receipt of a large amount of new experimental data on the mechanisms of gaseous swelling of ceramics [11][12][13][14][15]. According to traditional models of gas swelling for metals, helium accumulation occurs near grain boundaries, followed by deformation of the crystal structure, and leads to the formation of blisters containing helium and exerting bursting pressure on the filled cavity.…”