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

Extensive high temperature creep data are available in the literature for s uperplastic yttria-stabilized tetragonal zirconia polycrystals containing f rom 2 to 4 mol% of Y2O3 (termed YSZP). The different models developed to ac count for these experimental data are critically analyzed. It is shown that grain boundary sliding with threshold stress can predict the mechanical (e xperimental data found for n, p and Q),, and microstructural features in hi gh purity YSZP over the range of stresses, grain sizes and temperatures exa mined experimentally. The physical origin of the threshold stress is discus sed. This formalism is essentially similar to that used for explaining the superplastic behavior of metals. (C) 2000 Acta Metallurgica Inc. Published by Elsevier Science Lid. All rights reserved.