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

Abstract

Materials with high-temperature dimensional stability and resistance to radiation damage are receiving increasing attention in advanced nuclear energy systems. In this research, (Sm0.2Eu0.2Gd0.2Dy0.2A0.2)2W3O12-type (A = Y, Tm,Ho) high-entropy ceramics is presented. The coefficients of thermal expansion of (Sm0.2Eu0.2Gd0.2Dy0.2Y0.2)2W3O12 (HE-RE2W3O12) 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-RE2W3O12 and Gd2W3O12 maintained crystalline, but the lattice volume expansion rate of HE-RE2W3O12 (0.71 %) is much lower than that of Gd2W3O12 (1.49 %). Additionally, in the post-irradiated HE-RE2W3O12, 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-RE2W3O12 is rarely degrade. Overall, these results provide new insights for research on advanced nuclear materials in the future.