The effect of hot forging on the thermal and mechanical properties of spark plasma sintered SiC-TiB2-B4C Composites with CeO2 Addition

Sintering of SiC-TiB2-B4C composite was carried out by SPS at 1900 degrees C and hot forging was applied at 2050 degrees C to improve mechanical and thermal properties. A fully dense ceramic, with density of 3.08 g/cm3 was obtained after SPS and the properties of the composite improved after hot forging. During SPS sintering, TiB2 and graphite phases were in-situ formed consuming all TiC. Very strong orientation of graphite, coarsening of grain size and reduction in both liquid phase and porosities were observed after hot forging. While fracture toughness increased without compromising hardness and flexural strength, the thermal conductivity was doubled depending on the orientation of the in-situ formed graphite after hot forging. The hardness, fracture toughness, thermal conductivity, elastic modulus and density of the sintered and hot forged composites were measured as 32.2-32.8 GPa, 4.0-4.4 MPa.m1/2, 27.8-58.1 W m-1 K-1, 280-315 GPa and 3.12-3.08 g/cm3 respectively.