Evolutions of microstructural defects in high-entropy carbide ceramics under ion irradiations at room temperature

Abstract

This work studied and compared the evolutions of irradiation-induced microstructural defects in five high-entropy carbide ceramics (HECCs) at room temperature to reveal the irradiation resistances of HECCs and corresponding underlying mechanisms. The five HECCs exhibit high phase stabilities and no amorphization is observed up to 40 dpa. In-situ 800 keV Kr ion irradiation reveals similar evolutions of irradiation-induced defects. The densities of dislocation loops show non-monotonic variations, which reach the maximum at ∼ 2 dpa and then decrease due to the interactions with each other. In contrast, the sizes of dislocation loops increase monotonically with dose. (NbTaZrW)C exhibits the lowest defect densities and highest defect sizes, which is probably due to the high lattice distortion and its induced high defect recombination efficiencies. Based on the characterization results, it is deduced that the species of constituent elements play more important role in the defect behaviors than the number of constituent elements.