A three phase ceramic composite of 8 mol% Y2O3 stabilized ZrO2 (YSZ), SiO2, and Al2O3 was evaluated for potential high temperature superplasticity. The amorphous SiO2 content was 5 wt.%, and increasing additions of Al2O3 were made. The effect of varying the Y2O3 stabilizer concentration in ZrO2 was also studied. Samples sintered at 1200 °C contained only YSZ, Al2O3, and amorphous SiO2, but ZrSiO4 formed in the samples above 1300 °C. Mullite (3Al2O3 · 2SiO2) was not detected in any samples. Specimens of 1 wt.% Al2O3–YSZ/SiO2 had an anomalously high deformation rate of ∼2 × 10−4 s−1 at 1200 °C when compared to YSZ/SiO2 without Al2O3 (∼4 × 10-5 s−1). Higher amounts of Al2O3 additions decreased the strain rate. Extensive deformation of Al2O3 doped YSZ/SiO2 at 1200 °C induced the formation of ZrSiO4 due to enhanced reaction rates. This distributed, yet locally interconnected, zircon phase rapidly eroded the strain rate after ∼60% deformation.
Zircon Al2O3 Y2O3 High Temperature Deformation Initial Strain Rate
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
This is a preview of subscription content, log in to check access
This work was supported by the National Science Foundation under Grant No. DMR-0207197.