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 Es...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.展开更多
For understanding the deformation mechanism of AZ31 Mg alloy, two kinds of specimen, hot-rolled sheet and extruded bar were tested in tension at room temperature. Relatively small grain sizes ranging from 32 to 8.7μm...For understanding the deformation mechanism of AZ31 Mg alloy, two kinds of specimen, hot-rolled sheet and extruded bar were tested in tension at room temperature. Relatively small grain sizes ranging from 32 to 8.7μm are obtained by annealing at several temperatures. And then they were further cold-rolled with rolling angles of 0? 45?and 90? which is the angle between the rolling and the longitude direction of as-received specimen, and annealed at a temperature in recrystallization field. The yield stress were found from the stress—strain curve. The grain size dependence of the yield stress is found not in agreement with the Hall-Petch relationship. The texture of (0002) pole figure of each kind of specimen was tested by X-ray diffractometer. The specimen with strong basal texture shows large yield stress and low work-hardening rate, while the specimen with weak basal texture shows low yield stress and rapid work-hardening rate. These results are interpreted by the slip system activated in the different textures. A combined slip system was used to interpret the yield stress variation with the texture and the deformation mechanism was discussed.展开更多
文摘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.
文摘For understanding the deformation mechanism of AZ31 Mg alloy, two kinds of specimen, hot-rolled sheet and extruded bar were tested in tension at room temperature. Relatively small grain sizes ranging from 32 to 8.7μm are obtained by annealing at several temperatures. And then they were further cold-rolled with rolling angles of 0? 45?and 90? which is the angle between the rolling and the longitude direction of as-received specimen, and annealed at a temperature in recrystallization field. The yield stress were found from the stress—strain curve. The grain size dependence of the yield stress is found not in agreement with the Hall-Petch relationship. The texture of (0002) pole figure of each kind of specimen was tested by X-ray diffractometer. The specimen with strong basal texture shows large yield stress and low work-hardening rate, while the specimen with weak basal texture shows low yield stress and rapid work-hardening rate. These results are interpreted by the slip system activated in the different textures. A combined slip system was used to interpret the yield stress variation with the texture and the deformation mechanism was discussed.
