Mechanical and microstructural aspects of the high temperature plastic deformation of yttria-stabilized zirconia polycrystals

Abstract

The high-temperature plastic deformation of 6 mol% Y2O3-stabilized ZrO2 polycrystals with grain sizes of 1.8, 3.4 and 6.3 μm has been studied in compression between 1350 and 1450 °C in air at constant strain rate (between 1 × 10−5 and 2 × 10−4s−1) and under constant load (between 5 and 90 MPa). Two mechanical behaviours were observed depending on strain rate or stress levels: grain boundary sliding controlled by cation bulk diffusion, with an activation energy of 560 kJ/mol, and intergranular cavitation without plastic deformation of the grains.