Compressive creep behavior of an oxide-oxide ceramic composite with monazite fiber coating at elevated temperatures

The compressive creep behavior of a N610/LaPO4/Al2O3 composite was investigated at 900 and 1100 °C. The composite consists of a porous alumina matrix reinforced with Nextel™610 fibers coated with monazite in a symmetric cross-ply (0°/90°/0°/90°)s orientation. The compressive stress-strain behavior was investigated and the compressive properties were measured. Compressive creep behavior was examined for creep stresses in the −50 to −95 MPa range. Minimum creep rate was reached in all tests. At 900 °C, both monazite-containing and control (N610/Al2O3) specimens produced creep strains ≤ −0.05%. At 1100 °C, compressive creep strains approached −9%, and compressive creep strain rates, −10−7 s−1. Creep run-out defined as 100 h at creep stress, was achieved in all tests. Composite microstructure, damage and failure mechanisms, as well as effects of variation in microstructure on mechanical response were examined. Differences in processing and consequently in the composite microstructure had a significant effect on compressive response of the ceramic-matrix composite (CMC).