Characterization of sic-sic composites for application in current and advanced nuclear reactors

This paper describes the micro-mechanical properties of select silicon carbide - silicon carbide (SiC-SiC) composites as well as the validity and reliability of specific experimental techniques available for characterization. Four non-irradiated SiC-SiC samples fabricated through chemical vapor infiltration were cut, polished, and evaluated in this work. Nano-indentation was performed on all four samples for which the average hardness and reduced modulus were obtained in the fiber, and matrix. Across all samples, the trend was consistent; the matrix exhibited a higher average hardness over the fiber. However, the matrix hardness was significantly lower than values found in previous studies. Preliminary experiments concerning the interfacial shear strength were carried out via a fiber wedge push out test. The data collected found the internal friction coefficient to be 0.175 and the interfacial debond shear strength to be 174 MPa. These results are preliminary and will benefit greatly as a more refined testing procedure and larger sample set are investigated.