Creep behavior of fine-grained two-phase Al2O3-Y3Al5O12 materials

The compression creep behavior of fine-grained two-phase Al2O3-Y3Al5O12 (matrix) materials was investigated over the temperature range 1400-1500 °C under applied stresses between 3 and 20 MPa. The fine-grained two-phase Al2O3-Y3Al5O12 materials exhibited brief normal primary creep transients (less than 2%) prior to steady-state behavior with stress exponents close to unity, suggesting that the deformation was controlled by a diffusional creep mechanism. The activation energy for creep of the two-phase materials was between 592 and 612 kJ mol-1, which is within the range of values reported for creep of both single-phase Al2O3 and Y3Al5O12. The creep data of the two-phase materials correlated well with the predicted behavior based on the isostress model, suggesting that the creep behavior of the two-phase materials is most probably controlled by the faster deforming phase.