Irradiation response of Al2O3-ZrO2 ceramic composite under He ion irradiation

The dense Al₂O₃-ZrO₂ ceramic composite prepared by spark plasma sintering was irradiated by 500 keV He ions with different fluences and temperatures. The microstructural evolution and mechanical properties were investigated. The results showed that peak broadening and shifts at RT revealed by GIXRD and Raman are associated with damage induced microstrain and formation of point defects. The recovery at 500 °C suggested the reduction of irradiation induced damage. Compared with α-Al₂O₃, t-ZrO₂ exhibited a reverse trend in lattice parameters change and lattice expansion. Many helium bubbles with oblate and ribbon-like shape were mainly formed in α-Al₂O₃ grains at He concentration peak at 1.0 × 10¹⁷ ions/cm². With increasing of fluence at RT, ribbon-like helium bubbles developed into microcracks at 4.0 × 10¹⁷ ions/cm². Though evident structural changes, no full amorphization was observed at 4.0 × 10¹⁷ ions/cm². Formation of ribbon-like bubbles and microcracks is the main mechanism for degradation of mechanical properties of irradiated Al₂O₃-ZrO₂ composite.