Ion Beam Surface Modification of Y-TZP and Effects of Subsequent Annealing

Tetragonal zirconia polycrystals containing 3 mol% yttria (3Y-TZP), which show Superplasticity at high temperatures, were irradiated using 130 MeV Zr+" ions in the TANDEM accelerator facility at Tokai Research Establishment, JAERI. The irradiation induced atomic displacement damage was analyzed by TRIM code. Changes in the mechanical properties and fracture behavior caused by the ion irradiation and the effects of subsequent annealing were studied. The distribution of micro-indentation depth as a function of the indentation position from the irradiated surface to the specimen interior was also examined. The occurrence of compressive residual stresses and increases in hardness and fracture toughness were found in the as-irradiated surface region of the specimen. The subsequent annealing revealed that these quantities were decreased gradually with raising the annealing temperature. Probable causes of the generation of the residual stress and the changes in mechanical properties and fracture mode due to the irradiation are discussed.