Degradation Mechanism of Polycrystalline Silicon Carbide Fiber due to Air-Exposure at High Temperatures

Abstract

For description of the mechanical performance of SiC/SiC composites and for safety design for practical use, it is needed to reveal the degradation mechanism especially of fiber under the oxygen atmosphere. In the present work, the fracture behavior and microstructure of the polycrystalline silicon carbide fiber exposed in air at 1173-1873 K for 20 and 3.6 ks were studied with monofilament tensile test, microstructure observation and fracture toughness determination test using newly developed FIB(focused-ion-beam)-method.