Microstructure and mechanical properties of silicon carbide fibre-reinforced aluminium nitride composite

SiC continuous fibre (15 vol%)/AlN composite was fabricated using a sintering additive of 4Ca(OH)₂ · Al₂O₃ by hot-pressing at 1650 °C and 17.6 MPa in vacuum. Analytical transmission electron microscopy and scanning electron microscopy were used to investigate the microstructure of as-fabricated and crept SiC fibre/AlN composites. The room-temperature mechanical and high-temperature creep properties of the composite were investigated by four-point bending. The incorporation of SiC fibre into AlN matrix improved significantly the room-temperature mechanical properties. This improvement could result from the crack deflections around the SiC fibres. However, the incorporation degraded severely the high-temperature creep properties under oxidizing atmosphere. This could be attributed to the development of the pores and various oxides at the matrix grain boundary and matrix/fibre interface during creep test.