Tensile Stress Rupture of SiCf/SiCmMinicomposites with Carbon and Boron Nitride Interphases at Elevated Temperatures in Air

摘要: The stress-rupture properties of precracked minicomposites were determined in air at temperatures the range 700--1,200 C. minicomposite systems consisted a single tow Nicalon or Hi-Nicalon fibers with carbon boron nitride (BN) interphases and chemical-vapor-infiltrated silicon carbide (CVI-SiC) matrix. results compared to single-fiber data composite literature. Severe embrittlement occurred for interphase minicomposites. However, BN showed only mild degradation rupture properties. This was true even though reacted vaporized because water vapor atmosphere intermediate (700--950 C) glass formation higher (950--1,200 C). severe that composites due Nicalon-fiber from environment. BN-interphase controlled by fiber less than {approximately}900 C greater {approximately}1,100 In {approximately}900--1,100 C, most fused matrix layer formed between matrix, resulting stress concentrations led themore » minicomposites.« less