Tensile Creep of Melt-Infiltrated SiC/SiC Composites with Unbalanced Sylramic-iBN Fiber Architectures

The in-plane creep-rupture behavior at 1315 degrees C was measured in air for melt-infiltrated SiC/SiC composite panels reinforced by Sylramic-iBN SiC fibers with unbalanced three dimensional (3D)-woven and 2D-braided fiber architectures that displayed a high stress for the onset of through-thickness matrix cracking at room temperature. It was found that a significant improvement in the creep-rupture behavior at 1315 degrees C was observed, if the primary fiber direction was aligned with the direction of stress. Optical microscopy was used to examine postcreep microstructures in order to determine the extent of matrix cracking, and long-time rupture stress and strain conditions were identified for the different architectures.