Compressive creep behavior of SiC fiber-reinforced mullite matrix composites

The compressive creep behavior of monolithic mullite and 40 vol% SiC fiber-reinforced mullite matrix composite were investigated at the temperature from 1100 degrees C to 1200 degrees C in air atmosphere. Two kinds of composite specimens were used in this study: one with the fiber direction parallel to the applied stress, and the other with the fiber direction perpendicular to the stress. The results showed that two kinds of composite specimens both exhibit excellent creep resistance, compared with the creep behavior of monolithic mullite, though there is a creep anisotropy between the two kinds of composite specimens. The improvement in creep resistance of the former is realized by shedding most part of the applied stress on the SIC fibers, and the improvement in creep resistance of the latter is produced by the SiC fibers inhibiting the sliding of mullite matrix grains along the fibers. The improvement mechanisms of the composites were confirmed further by their creep-recovery study.