The tensile creep behavior of superplastic tetragonal zirconia doped with small amounts of SiO2

The constant stress tensile creep behavior is reported of a tetragonal zirconia (3Y-TZP) with a grain size of 0.27 mu m as a function of SiO2 addition up to 2.5 wt%. The effects of SiO2 addition are classed into two definite regimes. In the first regime, up to 0.3 wt% additions, both stress exponent, n, and apparent activation energy, Q, decrease steeply and strain rate, (epsilon) overdot increases also steeply as the amount of SiO2 increases. In the second regime, with additions more than 0.3 wt%, n and Q remain almost constant while (epsilon) overdot increases gradually as the amount of SiO2 increases. The appearance of the respective regimes is closely correlated with grain boundary microstructures modified by the SiO2 addition. (C) 1997 Elsevier Science S.A.