Microstructural characterisation of an alumina/mullite composite tested in creep

This paper presents the results of creep testing of a ceramic matrix composite (CMC) in which a matrix of mullite (Al2O3/SiO2) and SiOC (Umox) is reinforced with a cross-ply architecture [(0/90)3]s of alumina (Nextel™610) fibres. Seven specimens have been tested under different loading (50–80 MPa) and temperature (1000–1200 °C) conditions. The interfacial behaviour has been analysed through fibre push-in tests performed with a nanoindentation system. Fractographic and microstructural analyses have been performed in each specimen looking for correlations between measured parameters such as fibre and bundle pullout, crack density, crack path, oxidation, and interfacial mechanical properties.