Temperature dependent evolution of dislocation loops in YSZ under high energy electron irradiation

Abstract

Yttria stabilized cubic zirconia (YSZ) is one of the potential matrices to be used in hostile radiation environment. In the present study, the evolution of dislocation loops in sintered YSZ specimens was investigated in situ in high voltage electron microscopes under irradiation with high energy electrons as functions of electron energy from 1.25 to 3.0 MeV and irradiation temperature from 300 to 773 K. In situ microstructure observation reveals that under 1.25 MeV electron irradiation at 300 to 673 K, no dislocation loops were formed up to a fluence of 4.5×1026 m-2. Under irradiation with 2.0 and 3.0 MeV electrons, the microstructure evolution was strongly dependent on electron energy and irradiation temperature, resulting the formation of perfect dislocation loops and/or oxygen-type dislocation loops. Results reveal an importance of the ratio of displacement damage rate between oxygen sublattice and cation sublattice, and their mobility on the nucleation-and-growth of defects in YSZ.