HREM and EDS analysis of sintered SiC fibre reinforced MAS glass composites

A polycrystalline-sintered SiC fibre reinforced magnesium-aluminosilicate (MAS) glass composite was fabricated by hot-pressing. The unidirectionally reinforced composite with a fibre volume fraction (V_f) of 50% and density of 2.84 g cm^-3 was obtained. The matrix was composed of a glass phase, and Mg₂Al₄Si₅O₁₈ and ZnAl₂O₄ crystalline phases. The three-point flexural strength and quasi-static adsorbed energy of the composites at room temperature were 500 MPa and 6000 J m^-2, respectively. A SiO₂-rich glass layer was formed around the fibre. Furthermore, a 5-40 nm wide carbon-rich silicon-oxycarbide interphase with a layered structure was determined between the fibre and the SiO₂-rich glass layer. The formation of both layers was caused by super-saturated oxygen which was contained in the raw glass powder. The preferable mechanical properties are due to the nano-scale interphase which allows for suitable interfacial bonding.