Thermal and Mechanical Properties of SiC–TiC0.5N0.5 Composites

Abstract

SiC–TiC0.5N0.5 composites were fabricated from β‐SiC and TiN powders with 2 vol% equimolar Y2O3–Sc2O3 additives by conventional hot pressing. Thermal and mechanical properties of the SiC–TiC0.5N0.5 composites were investigated as a function of initial TiN content. Relative densities of ≥98.9% were achieved for all samples. The addition of a small amount of TiN increased thermal conductivity, flexural strength, and fracture toughness of SiC ceramics. However, further addition of TiN in excess of 10 and 20 vol% deteriorated both thermal conductivity and flexural strength of the composites, respectively. In contrast, the fracture toughness of the composites increased continuously from 4.2 to 6.2 MPa∙m1/2 with increasing initial TiN content from 0 to 35 vol%, due to crack deflection by TiC0.5N0.5. The maximum values of thermal conductivity and flexural strength were 224 W/m K for a 2 vol% TiC0.5N0.5 and 599 MPa for a 10 vol% TiC0.5N0.5 composite.