Study on the internal friction mechanism of C/SiC composites in different corrosion stage

The effects of microstructure and composites evolution of C/SiC composites after corrosion on the internal friction were investigated and the internal friction mechanisms at different corrosion stages were discussed. The studies presented that the internal friction of C/SiC composites with defects was sensitive to the low frequency and high amplitude. In the initial corrosion stage, there was little change in interface of C/SiC composites and the corrosion under high temperature released the thermal stress at the interface, which decreased the internal friction. As the interface eroded in samples, the weaken interface became the important source of internal friction and improved the internal friction of samples. With the further development of the corrosion, SiC matrix in C/SiC composites was oxidized. The glassy oxide filled the cracks and restrained the matrix deformation, resulting in the little decrease in the internal friction of samples with high content oxide.