MICROSTRUCTURE AND MECHANICAL-PROPERTIES OF SIC PLATELET REINFORCED (ALPHA+BETA) SIALON CERAMIC COMPOSITES

The effect of the SIC platelet content on rite microstructure and mech anical properties of(alpha + beta) sialon ceramic composites at room t emperature has been investigated. The results show that the composites are composed of SiC platelet reinforcement and a matrix containing al pha and beta sialon grains and a small amount of crystallised grain bo undary phase. High resolution electron microscopy observations showed that the platelets directly bonded to the matrix. The results show tha t fracture toughness of the composites was increased by the addition o f 0-30 vol.-%SiC platelets and a decrease in flexural strength was mea sured with increasing SIC platelet content. Toughening mechanisms of S iC platelets are also presented. (C) 1998 The Institute of Materials.