Effect of direct and alternating current (DC and AC) fields on creep behavior of 8 mol% Y2O3 stabilized cubic ZrO2 polycrystal

The effect of electric field/current on creep deformation was examined in fine-grained 8 mol% Y2O3 stabilized cubic ZrO2 (8Y-CSZ) under direct and alternative current (DC and AC) conditions. Even at similar sample temperature of 1160–1170 °C, although the electric fields/currents accelerate the deformation of 8Y-CSZ, the acceleration effect (athermal effect), which cannot be explained by an increase of the sample temperature due to Joule heating, is much pronounced in AC than in DC. Under the deformation without the electric field/current, the creep behavior can be characterized by diffusional creep processes with a stress exponent of n ≈ 1, whereas under DC and AC, the predominant mechanism changes to grain boundary sliding (GBS) with n ≈ 2. This indicates that the athermal effect under the electric field/current changes the deformation mechanism from diffusional creep to GBS mechanisms by enhancing GBS and its rate controlling process of cation diffusivity, especially in AC.