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.
In this work, the irradiation response of A 2 Ti 2 O 7 (A represents rare earth elements of Gd, Dy, Ho, Er, Yb and Nd) series ceramics were systematically studied under 3 MeV Au 2+ ions. The structural changes pre- and post-irradiation were characterized using X-ray diffraction (XRD), grazing incidence X-ray diffraction (GIXRD) and Raman spectroscopy . After heavy ion irradiation , all the samples undergo structural transformations from ordered pyrochlore to disordered fluorite and then to amorphous phase. The sample surface became fully amorphous when exposed to the maximum irradiation dose. The 5RETO high-entropy pyrochlore exhibits the lowest rate of amorphization during the process of structural transformation. The cation radius ratio and mixed entropy are the primary factors influencing amorphization rate. The cation radius ratio shows a strong positive correlation with the amorphization rate, while the mixed entropy demonstrates a weak negative correlation with the amorphization rate. The cation radius ratio can thus serve as a reliable indicator for predicting the radiation resistance of high-entropy pyrochlore ceramics.
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