Interface properties of YPO{sub 4}/Y{sub 3}Al{sub 5}O{sub 12} systems: A double-sandwich specimen and a fiber model composite

Interface properties of a YPO{sub 4}/Y{sub 3}Al{sub 5}O{sub 12} system were studied on a double-sandwich specimen by a double-shear test and on a fiber model system by a fiber pushout test. The double-sandwich specimen was composed of two YPO{sub 4} interlayers separated by the Y{sub 3}Al{sub 5}O{sub 12} matrix. The fiber model system consisted of a single crystal YAG fiber/YPO{sub 4} coating/Y{sub 3}Al{sub 5}O{sub 12} matrix composite. Mode II interfacial fracture energy, {Gamma}{sub II}, of the YPO{sub 4}/Y{sub 3}Al{sub 5}O{sub 12} system was obtained from the double-shear {Gamma}{sub II} test and the fiber pushout {Gamma}{sub II} test. Except for {Gamma}{sub II}, interfacial shear debond and frictional strengths were obtained from the double-shear {Gamma}{sub II} test. Analyzing the fiber pushout data with the Liang-Hutchinson fiber pushout model, the interface properties, (e.g. clamping stress and coefficient of friction), along with {Gamma}{sub II} can be extracted. A double cleavage drilled compression test for mode I interface energy, and 4-point flexure testing of notched bars for mixed-mode interface energy were attempted.