Effects of high-temperature environments on flaw generation and fracture behavior of SiC/SiC composites

[摘要] Flaw generation and fracture behavior in Nicalon fiber-reinforced SiC matrix composites are influenced by high temperatures. We evaluated the effects by measuring strength at several temperatures ranging from 800 to 1300 degrees C, and by microstructural characterization. While composite strength increased from approximate to 400 MPa at room temperature to approximate to 532 MPa at 800 degrees C, it decreased to approximate to 270 MPa at 1300 degrees C. Such degradation of composite strength at high temperature is believed to be related to fiber degradation. In-situ fiber strength in composites tested at room and elevated temperatures was estimated by fractographic techniques. The in-situ strength of fibers in composites was significantly lower than that of as-received fibers. This decrease is believed to be related to flaws that develop during processing and to exposure to elevated-temperature service environments.

[发布日期] 1996-05-01

[效力级别]  Proceedings Paper

[关键词] high-temperature environments;fracture;fibres;composites;SiC