COMPARATIVE STUDY OF TENSILE PROPERTIES OF UNI-DIRECTIONAL SINGLE-TOW SIC-MATRIX COMPOSITES REINFORCED WITH VARIOUS NEAR-STOICHIOMETRIC SIC FIBERS

摘要

Tensile properties of unidirectional single tow SiC/SiC mini-composites reinforced with four different commercial and experimental near-stoichiometric SiC fibers were evaluated. The composites reinforced with Hi-Nicalon? Type-S (HNLS), Tyranno?-SA3, experimental Sylramic? and Sylramic-iBN fibers exhibited ultimate tensile stresses equivalent to ～73%, ～53%, ～69%, and ～81% of the single fiber strength at 25 mm, respectively. The ultimate tensile stress appeared to increase with the estimated interfacial sliding stress with the exception of the HNLS composite. The HNLS composite seems to have achieved the high tensile strength due to very low interfacial sliding stress arising from the larger radial tensile residual stress and its smooth fiber surface. In contrast, the fracture behavior of the other composites may have been strongly affected by clamping stress produced by the relatively rough fiber surfaces.