Abstract
Static grain growth behavior in 1 mol% of GeO2, TiO2, MgO or BaO-doped ZrO2–3 mol%Y2O3 (3Y-TZP) was examined at 1400°C with a special interest in dopant effect on superplastic flow stress in fine-grained 3Y-TZP. The static grain growth can be described as normal grain growth in single-phase ceramics, and growth constant K for each material is in the order of 10% flow stress of the superplastic flow. The value of K in cation-doped TZP is correlated well with dopant cation’s ionic radius. Assuming activation energy for diffusivity of constituent ion can be given as a linear function of strain caused by difference in the ionic size of dopant cation, the dependence of the growth constant and the flow stress on the ionic radius can be described as a function of the ionic radius of the dopant cation. The activation energy for the diffusivity in cation-doped TZP estimated from the calculation is in good agreement with the experimental data. The small dopant effect on the superplastic flow stress is well described by the activation energy as the function of the dopant cation’s ionic size.
