High Temperature Slow Crack Growth in Silicon Carbide.
Abstract
Silicon carbide (SiC) has been selected as a material having good potential for high-temperature heat exchanger applications. At the temperatures where ceramic materials must operate in advanced engines, some strength degradation will occur. Therefore, it is important to characterize the strength properties in the elevated temperature regime to establish effective operational stress levels for heat exchanger component design. Thus, the primary objective of this program is the evaluation of safe working stresses for the application of silicon carbide material to heat exchangers. Failure of most ceramic materials with the potential for high-temperature structural application is controlled by the propagation of small preexisting flaws until fracture occurs. The primary determinant of safe working stress and service life is the nature of slow crack growth in these materials. The design of ceramic heat exchangers has been hindered due to the lack of reliable test methods for obtaining high-temperature material characteristics. Recently, however, a promising method for studying the high-temperature slow crack growth in ceramic material has been developed. This technique uses an essentially constant stress intensity specimen (the double torsion specimen) under constant displacement rate conditions. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 30, 1977
- Accession Number
- ADA039220
Entities
People
- David E. Schwab
- Harry A. Warren