Microstructure and mechanical properties of SiC platelet reinforced (α + β) sialon ceramic composites

The effect of the SiC platelet content on the microstructure and mechanical properties of (α + β) sialon ceramic composites at room temperature has been investigated. The results show that the composites are composed of SiC platelet reinforcement and a matrix containing α and β sialon grains and a small amount of crystallised grain boundary phase. High resolution electron microscopy observations showed that the platelets directly bonded to the matrix. The results show that fracture toughness of the composites was increased by the addition of 0-30 vol.-%SiC platelets and a decrease in flexural strength was measured with increasing SiC platelet content. Toughening mechanisms of SiC platelets are also presented.