Radiation damage effects in cubic-stabilized zirconia irradiated with 72 MeV I⁺ ions

Cubic-stabilized zirconia single crystals were irradiated using 72 MeV I⁺ ions in the TASSC accelerator facility at Chalk River Laboratory (to simulate a typical U or Pu fission fragment). Irradiations were performed over the fluence range 1 × 10¹⁸-5 × 10¹⁹ ions/m², at temperatures of 300, 770, and 1170 K. Damage accumulation was monitored using Rutherford Backscattering Spectroscopy and ion-channeling (RBS/C) techniques. At ambient temperature and at the highest I⁺ fluence used in these experiments (5 × 10¹⁹ I⁺/m²), RBS/C measurements revealed a rather high degree of lattice disorder. Specifically, the dechanneling parameter χ_min varied from 80% to greater than 90% over the depth probed by RBS/C (∼1 μm). Nano-indentation measurements on the same sample indicated decreases in elastic modulus, E, and hardness, H (both by about 9%). These results suggest that an alteration in structure beyond simple defect accumulation occurs under these irradiation conditions. However, transmission electronmicroscopy (TEM) observations and in particular microdiffraction measurements failed to reveal any structural transformations in the irradiated material.