Interfacial shear stresses in fiber-reinforced glasses

Abstract

The single fiber pull-out test has been used to measure interfacial properties of SiC fibers in soda-borosilicate glass matrices. Two parameters are examined: the SiC to free carbon ratio at the surface of the SiC fiber is varied to test the effect of interfacial chemistry and the glass expansion is varied to investigate the effect of residual stresses. A carbon coating is shown to be effective in preventing strong fiber-matrix bonding and oxidation of the SiC fibers by the glass. However, coatings with higher carbon content result in stronger bonding to the soda-borosilicate glass. Both the interfacial shear strength and the frictional shear stress increase linearly with residual stress and reach a maximum of nearly double the strain-free value above which the interfacial strength decreases as a result of radial crack formation in the glass matrix. The measured interfacial shear properties are also found to be stress rate dependent.

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