Gang Yao,Xue-Peng Liu,Zhi-Yuan Zhao,Zhi-Hao Zhao,Lai-Ma Luo,Ji-Gui Cheng,Xiang Zan,Qiu Xu,Yu-Cheng Wu
In this study, W-(Y 0.9 La 0.1 ) 2 O 3 composite powders are fabricated by means of a combination of wet chemical method and spark plasma sintering. We systematically study the sintering and densification behavior of W-(Y 0.9 La 0.1 ) 2 O 3 composite powders at different temperatures and pressures. The results indicate that ultrafine tungsten-based composites with a dispersed distribution of (Y 0.9 La 0.1 ) 2 O 3 particles can be achieved under optimized temperature and pressure conditions. The optimized pressure and sintering temperature for W-(Y 0.9 La 0.1 ) 2 O 3 composites are identified to be 75 MPa and 1600 °C, respectively. In addition, the surface damage behavior of W-(Y 0.9 La 0.1 ) 2 O 3 composites induced by the laser thermal shock and helium ion irradiation are also investigated. It is shown that the presence of holes greatly enlarges the helium retention during helium ion irradiation and promotes the melting caused by local overheating during laser thermal shock. We find that the fine-dispersed distribution of (Y 0.9 La 0.1 ) 2 O 3 particles in the tungsten-based composites can effectively improve the resistance of helium ion irradiation and laser thermal shock. We hope that these findings could provide some guidance and reference for the fabrication of large-sized tungsten-based materials in fusion engineering.
High-entropy carbide ceramics (Ti 0.25 Zr 0.25 Nb 0.25 Ta 0.25 )C with a single-phase rock-salt structure were prepared by hot-pressed sintering. These ceramics were irradiated with 500 keV He 2+ ions to fluences of 5 × 10 16 ions·cm −2 and 1 × 10 17 ions·cm −2 at room temperature to 700 °C. The investigation into irradiation-induced lattice swelling was conducted using grazing incident X-ray diffraction, while microstructure evolution was characterized through transmission electron microscopy . Lattice expansion induced by the He ion irradiation was identified, which highly depends on the irradiation temperature and fluence. Notably, the lattice expansion diminishes with rising irradiation temperature primarily as a result of the dynamic annealing effect . Nano-sized He bubbles , with an average diameter of less than 1 nm were uniformly dispersed within the grain interior. Notably, He bubble nucleation does not exhibit a preference for grain boundaries at 700 °C irradiation. Following He ion irradiation at 350 °C and 700 °C, dislocation loops of 1/3<111> and 1/2<110> with sizes in the ranges of several nanometers were observed. The present study provides insights into high-entropy carbide ceramics with potential applications in the field of nuclear energy.
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