High temperature mechanical characteristics of superplastic yttria-stabilized zirconia. An examination of the flow process

Abstract Extensive high temperature creep data are available in the literature for superplastic yttria-stabilized tetragonal zirconia polycrystals containing from 2 to 4 mol% of Y2O3 (termed YSZP). The different models developed to account for these experimental data are critically analyzed. It is shown that grain boundary sliding with threshold stress can predict the mechanical (experimental data found for n, p and Q) and microstructural features in high purity YSZP over the range of stresses, grain sizes and temperatures examined experimentally. The physical origin of the threshold stress is discussed. This formalism is essentially similar to that used for explaining the superplastic behavior of metals.