Characterization of Mechanical Behavior and Fractographic Observations on Compglas SIC/LAS Composites

Results are presented for unidirectional tensile tests on Compglas™ Nicalon™ SiC fiber/LAS matrix composites. These results, for tensile stress-strain behavior, are compared with previous results and with predictions for tensile behavior derived from the Aveston theory for brittle matrix fiber composites. The results suggest quite low values for the fiber-matrix interfacial shear strength and that the interfacial strength may be nearly optimum for strength and toughness. Observations are also presented based on fractographic measurements on fibers tested individually in tension, and on fibers fractured in situ in the composite. These measurements provide quantitative information on the strength distribution of the SiC fibers as present in the composite.