Irradiation damage in xenon-irradiated α-Al2O3 before and after annealing

Abstract

The irradiation damage build-up of α-Al2O3 under Xe20+ ion irradiation has been investigated by a combination of Raman spectroscopy and transmission electron microscopy. α-Al2O3 crystalline was irradiated with 5 MeV Xe20+ ions to fluences of 1 × 1014 cm−2, 5 × 1014 cm−2, 1 × 1015 cm−2 and 5 × 1015 cm−2 at room temperature. No amorphous phase was formed under the experimental condition. The Raman intensities of feature peaks of Al2O3 decrease after Xe ion irradiation. The interstitial-type dislocation loops with Burgers vectors of b = 1/3 < 10-11> on the {10-10} and (0001) habit planes were found. The formation of basal and prism dislocation loops is related to the lattice damage and position. After annealing, the Raman intensities of feature peaks of Al2O3 increases with annealing temperature. With annealing at 1500℃ for 30 min, lattice defects were completely annealed out in the near surface region. Meanwhile, long dislocations and facet cavities on long dislocations were found in the Xe deposition region. Some lattice defects beyond the projected region were found due to the diffusion toward deep region during thermal annealing.