High-temperature dimensional stability and radiation behavior of high-entropy rare earth tungstate ceramics.

Materials with high-temperature dimensional stability and resistance to radiation damage are receiving increasing attention in advanced nuclear energy systems. In this research, (Sm 0.2 Eu 0.2 Gd 0.2 Dy 0.2 A 0.2) 2 W 3 O 12 -type (A = Y, Tm,Ho) high-entropy ceramics is presented. The coefficients of thermal expansion of (Sm 0.2 Eu 0.2 Gd 0.2 Dy 0.2 Y 0.2) 2 W 3 O 12 (HE-RE 2 W 3 O 12) is 7.21 × 10−6 K−1 at 300–1100K, which is the lowest among the three synthesized high-entropy ceramics and indicates good dimensional stability at high temperatures. After irradiation with Kr+ fluence of 4.58 × 1016 ions/cm2 at 400 °C, both HE-RE 2 W 3 O 12 and Gd 2 W 3 O 12 maintained crystalline, but the lattice volume expansion rate of HE-RE 2 W 3 O 12 (0.71 %) is much lower than that of Gd 2 W 3 O 12 (1.49 %). Additionally, in the post-irradiated HE-RE 2 W 3 O 12 , the Raman spectra vibration peak remained unchanged and no radiation-induced segregation was observed. Nanoindentation tests displayed that the degradation of hardness and elastic modulus in HE-RE 2 W 3 O 12 is rarely degrade. Overall, these results provide new insights for research on advanced nuclear materials in the future. [ABSTRACT FROM AUTHOR]