Ultrahigh Temperature Assessment Study: Ceramic Matrix Composites

Abstract

As part of the U.S. Air Force initiative to develop high temperature materials for use in future gas turbine engines, a literature survey coupled with an assessment of recently completed experimental programs sponsored by the Air Force was made to evaluate prospective materials capable of operating at 1650 deg C or above in oxidizing environments. The assessment reviews fundamental considerations associated with the use of ceramics and ceramic matrix composites in representative environments and includes discussions on potential performance requirements. Key material categories (e.g., borides, carbides, nitrides, silicides, beryllides, and oxides) are evaluated with respect to their strengths and weaknesses. The reinforcements available for high temperature composite applications are reviewed and several prospective composite systems considered. A principal conclusion relative to possible uses for long-term man-rated gas turbine engines is that oxide/oxide composites-have the best potential for functional use in oxidizing environments above 1650 deg C provided adequate single-crystal reinforcement fibers can be developed. Several nonoxide materials and composites were identified for possible uses in short- duty cycle non-man-rated applications. In addition to materials development, there will be critical need for high-temperature test facilities that can be operated in representative oxidizing environments.... Ceramics, Composites, Ultrahigh temperature, Matrix, Fiber reinforcement, Oxidation, Fracture toughness, Strength, Creep, Fatigue.