RADIATION-DAMAGE EFFECTS IN CUBIC-STABILIZED ZIRCONIA IRRADIATED WITH72 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 per formed over the fluence range 1 x 10(18) -5 x 10(19) ions/m(2), at tem peratures of 300, 770, and 1170 K. Damage accumulation was monitored u sing Rutherford Backscattering Spectroscopy and ion-channeling (RBS/C) techniques. At ambient temperature and at the highest I-divided by fl uence used in these experiments (5 x 10(19) I+/m(2)), RBS/C measuremen ts revealed a rather high degree of lattice disorder. Specifically, th e dechanneling parameter chi(min) varied from 80% to greater than 90% over the depth probed by RBS/C (similar to l mu m). Nano-indentation m easurements 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 electronmicroscop y (TEM) observations and in particular microdiffraction measurements f ailed to reveal any structural transformations in the irradiated mater ial. (C) 1998 Elsevier Science B.V. All rights reserved.