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

Ceramic composites are promising candidates as structural materials for future fission and fusion reactors. In present work, Al 2 O 3 -ZrO 2 -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 Al 2 O 3 -ZrO 2 -SiC composite were observed up to fluence of 1.72 × 10 18 ions/cm 2 . Transmission electron microscopy observations showed that throughout the entire irradiation region, nano-sized helium bubbles are mostly distributed in Al 2 O 3 grains and partly in ZrO 2 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 Al 2 O 3 -ZrO 2 -SiC composite exhibits remarkable resistance to He-ions irradiation.