Helium irradiation induced microstructural damages and mechanical response of Al2O3-ZrO2-SiC composites

Abstract

Ceramic composites are promising candidates as structural materials for future fission and fusion reactors. In present work, Al2O3-ZrO2-SiC ternary ceramic composites were irradiated with 2.0 MeV He-ions at 300 and 800 ℃. Grazing incidence X-ray diffraction results confirmed that there was irradiation induced shift and broadening of diffraction peaks, but no amorphization of Al2O3-ZrO2-SiC composite were observed up to fluence of 1.72 × 1018 ions/cm2. Transmission electron microscopy observations showed that throughout the entire irradiation region, nano-sized helium bubbles are mostly distributed in Al2O3 grains and partly in ZrO2 grains, while no detectable bubbles are observed in SiC grains. No obvious agglomeration of bubbles was found at grain/phase boundaries. By using nanoindentation technique, slight hardening or softening was confirmed for the samples irradiated at 300 and 800 ℃ respectively. The absence of amorphization and surface exfoliation indicating the Al2O3-ZrO2-SiC composite exhibits remarkable resistance to He-ions irradiation.