Radiation damage in pure and helium-doped α-Al₂O₃ in the HVEM Quantitative aspects of void and aluminium precipitate formation

Abstract

Single crystal α-Al₂O₃, both pure and helium-doped, has been irradiated with 1 MV electrons in a HVEM at several temperatures in the range 880–1130 K. Voids and aluminium precipitates were found to form after electron doses of ∼ 17 and ∼40 MC m⁻², respectively. The number and size distribution of both voids and aluminium precipitates were determined, and the volume fraction of both kinds of defect were found to follow a power law of dose with an exponent of 0·5–0·6. An activation energy for void formation of 0·96 ± 0·1 eV was obtained, and void swelling was found to be only slightly increased by helium doping. The activation energy for aluminium precipitate formation was found to be 1·35 ± 0·15 eV.