Polycrystalline samples were bombarded using 3 different sets of conditions in order to determine the effects of displacement damage and transmutation product formation. The specimens were implanted with H, He and alone, or were bombarded with 4MeV Ar+ ions alone, or were pre-implanted with H, He and C and were then bombarded with 4MeV Ar+ ions. The bombarded specimens were studied by means of transmission electron microscopy, after bombardment to damage levels of between 0.6 and 30dpa at 260 to 810C. In both materials, no irradiation effects were observed in specimens which had been implanted with H, He and C alone. Pre-injected species did not have a marked effect upon the dislocation loop size or density in Ar+-bombarded specimens. In the case of alumina, cavities formed in all of the Ar-bombarded specimens; with or without pre-implantation. In the case of the spinel, cavity formation was observed only in pre-implanted specimens which were bombarded with Ar+ ions at relatively high temperatures and/or doses.

R.Yamada, S.J.Zinkle, G.P.Pells: Journal of Nuclear Materials, 1994, 209[2], 191-203