Synergistic roles of carbon fibres and ZrO2 particles in strengthening andtoughening Li-alpha-sialon composites

Carbon fibre reinforced Li-a-sialon ceramic matrix composites have been fab ricated by a process of slurry infiltration followed by hot-pressing. The r oles of both carbon fibres and ZrO2 particles in the strengthening and toug hening of Li-oc-sialon ceramic matrix composites are discussed. SEM observa tions show that microcracks in the matrix resulting from the thermal mismat ch between the carbon fibres and the matrix can be eliminated by the additi on of the ZrO2 and a considerable amount of fibre pullout was achieved duri ng fracture failure of the composites. Measurement of mechanical properties indicates that a synergistic strengthening and toughening has been achieve d with bending strength and fracture toughness of similar to 410 MPa and si milar to 12 Mpa m(1/2) respectively. (C) 2001 Elsevier Science Ltd. All rig hts reserved.