Tensile and Stress‐Rupture Behavior of SiC/SiC Minicomposite Containing Chemically Vapor Deposited Zirconia Interphase

Abstract

The tensile and stress‐rupture behavior of SiC/SiC minicomposite containing a chemically vapor deposited (CVD) ZrO 2 interphase was evaluated. Fractographic analyses showed that in situ fiber strength and minicomposite failure loads were strongly dependent on the phase contents and microstructure of the ZrO 2 interphase. When the ZrO 2 interphase structure possessed a weakly bonded interface within the dense ZrO 2 interphase coating layer, the interphase sufficiently protected the fiber surface from processing degradation and promoted matrix crack deflection around the fibers. With this weakly bonded interphase, the stress‐rupture properties of SiC/SiC minicomposite at 950° and 1200°C appeared to be controlled by fiber rupture properties, and compared favorably to those previously measured for state‐of‐the‐art BN fiber coatings.