Thermal Exposure and Thermal Protection of a Ceramic Fiber/Glass Matrix Composite
Abstract
Thermal exposure in air has been shown to embrittle a ceramic fiber/glass matrix composite by the infiltration of oxygen to the fiber-matrix interface. Samples exposed at sufficiently high temperature demonstrate less embrittlement than those exposed at intermediate temperatures, due to a material flow which seals the surface. It is shown that the surface protection against embrittlement provided by a short, high-temperature thermal treatment remains in force for materials subsequently exposed under both loaded and unloaded conditions. In comparing results from plates processed under different conditions, it was found that the composites embrittled at two different rates-either quickly or slowly. The rate of embrittlement was not predictable from testing as-fabricated materials. A series of processing tests were carried out to determine the reason for the difference in the rapidity of embrittlement. The rapid embrittlement effects is believed to be attributable to an excess of carbon in the as fabricated matrix. The thermal exposure treatment is effective with both types of composites (those which embrittle quickly and those which embrittle slowly).
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1991
- Accession Number
- ADA251131
Entities
People
- L. P. Zawada
- R. C. Wetherhold
Organizations
- University at Buffalo