Micro-compression testing of gold ion irradiated zirconolite glass-ceramics as nuclear waste forms

Abstract The mechanical properties of zirconolite glass-ceramics designed for immobilising actinide-rich nuclear wastes, have been investigated through micro-compression tests pre and post 12 MeV gold ion irradiation at room temperature to a peak damage level of 100 displacements per atom (dpa). Whilst zirconolite crystals have become amorphized because of irradiation, transmission electron microscope analysis found no voids within the irradiated zirconolite. Nevertheless, voids of ∼25 nm in diameter were observed within the glass phase and appear to be homogeneously distributed. Surprisingly, micro-compression testing found the zirconolite glass-ceramic to exhibit a lower modulus, lower compression yield and greater toughness post irradiation.