プッシュアウト法によるSiC_f/BN/SiC複合材料の界面力学特性評価

抄録

SiC fiber reinforced SiC matrix (SiC/SiC) composites are considered as an attractive candidate for the component of next generation gas turbine engines. Generally, mechanical properties of SiC/SiC composites are strongly influenced by interfacial properties between fiber and matrix because load transfers from matrix to fiber must occur through the interface. In this study, mechanical properties of SiC/SiC composite with BN interphase were examined. The interfacial properties were investigated by single fiber push-out tests. The fracture surfaces and interfacial microstructures between fiber and matrix were also observed by FIB-SEM, and TEM. TEM observation shows that BN interphases were composed of high crystalline structure. Interfacial shear stress measured by push-out tests is increased with decreasing the interphase thickness in a range of 0.8-2.0 µm. Optimum interphase thickness to occur crack deflection was estimated from Γ_i/Γ_f value.