Influence of Oxidation Damages on Mechanical Properties of SiCSiC Composite Using Domestic Hi-Nicalon Type SiC Fibers

Abstract EN

Here, we show that when the oxidation treatment temperature exceeded 600°C, the tensile strength of SiC/SiC begins to decrease.

Oxidation leads to the damages on the PyC fiber/matrix interface, which is replaced by SiO2 at higher temperature.

The fracture mode converts from fiber pull-out to fiber-break as the fiber/matrix interface is filled with SiO2.

Oxidation time also plays an important role in affecting the tensile strength of SiC/SiC.

The tensile modulus decreases with temperature from RT to 800°C, then increases above 800°C due to the decomposition of remaining CSixOy and crystallization of the SiC matrix.

A special surface densification treatment performed in this study is confirmed to be an effective approach to reduce the oxidation damages and improve the tensile strength of SiC/SiC after oxidation.