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

Abstract

Sintering of SiC-TiB₂-B₄C composite was carried out by SPS at 1900°C and hot forging was applied at 2050 °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.m^1/2, 27.8–58.1 W‧m⁻¹‧K⁻¹, 280–315 GPa and 3.12–3.08 g/cm³ respectively.