Effect of Interfacial Strength of SiC/SiC Composites Fabricated by Hot-Pressing and Chemical Vapor Infiltration Method on their Mechanical Properties

The interfacial strength of SiC/SiC composites fabricated by hot-pressing (HP) and chemical vapor infiltration (CVI) method was measured by push-in test, and the effect of interfacial strength on the fracture behavior of SiC/SiC composites was investigated. Maximum strength and fracture energy of the CVI-SiC/SiC composite was higher than those of the HP-SiC/SiC composite due to lower interfacial shear sliding strength and higher fiber strength. The SiC/SiC composite hot-pressed at 1750 °C had a higher interfacial shear sliding strength and lower fiber strength, resulting in low maximum strength and fracture energy. The SiC/SiC composite hot-pressed at 1650 °C showed a lower maximum strength and higher fracture energy in spite of a lower interfacial shear sliding strength and higher fiber strength. In this case, the delamination between fiber and the matrix occurs easily.