Paper number 1325

IMPORTANCE OF FIBER/MATRIX BONDING IN SIC/BN/SIC ON MECHANICAL AND INTERFACIAL PROPERTIES

F. Rebillat, J. Lamon and A. Guette

Laboratoire des Composites Thermostructuraux,
UMR 5801 (CNRS-SNECMA/SEP-UB1-CEA),
3 allée de la Böetie, 33600 Pessac, France

Summary

SiC/BN/SiC composites were produced by Chemical Vapor Infiltration of a fiber preform. Three kinds of BN interphases were deposited on the fibers: (i) a poorly organized, (ii) a highly crystallised and (iii) a bilayered interphase with the low organized BN against the fiber followed by the highly crystallized one. The mechanical behavior of SiC/BN/SiC composites was determined under tensile loading at room temperature. The interfacial properties were extracted from stress-strain and fiber push-out test curves. Relationships between the stress-strain behavior and the measured interfacial parameters could be established for the types of BN interphases. Further, trends in the evolution of interfacial properties with the BN structure (and so, with BN interphase processing conditions) were anticipated. A significant effect of the fiber/coating bond strength on the interfacial damage is evidenced. Finally, the efficiency of boron nitride as an interphase is compared to the that of pyro-carbon.

Keywords

boron nitride, interphase, 2D composite, microcomposite, interfacial parameters, tensile test, push-out.