MEASUREMENT OF DYNAMIC MECHANICAL PROPERTIES OF ADVANCED CERAMICS AND CERAMIC MATRIX COMPOSITES AT TEMPERATURES ABOVE 1000°C

摘要

In recent years, advanced ceramics and ceramic matrix composites have found increasing structural applications. One such application is in advanced combustion engine components. Since these components operate in vibratory environments, knowledge of high temperature dynamic mechanical properties (internal damping and stiffness) of the materials is of great significance. Such knowledge is important not only for design but for a better understanding of the microstructural behavior of these materials under extreme environments. Even though the experimental techniques for characterizing dynamic mechanical behavior of metals, polymers and their composites have been extensively investigated and practiced, research shows that difficulties exist in conducting the corresponding experiments on ceramics or ceramic matrix composites due to their brittleness and the extreme temperatures that must be used. Based on our current research, this paper describes improved experimental approaches for measuring dynamic mechanical properties of ceramics and ceramic matrix composites at temperatures above 1000°C. The cantilever beam flexural vibration test and several different sample configurations are investigated, experimental results are compared and discussed, and finally, the experiences gained during the research are summarized.