Mechanical, thermal physical properties and thermal shock resistance of in situ (TiB2+SiC)/Ti3SiC2 composite

Abstract

Dense (TiB2+SiC)/Ti3SiC2 composite with 20 vol% TiB2 and 10 vol% SiC was synthesized by in situ reaction hot pressing. The room and high temperature mechanical and thermal physical properties, as well as thermal shock resistance of the composite were investigated and compared with SiC/Ti3SiC2 composite as prepared by the same process. The synergistic action of TiB2 and SiC produced a significant strengthening and toughening effect and (TiB2+SiC)/Ti3SiC2 composites exhibit superior room- and high-temperature mechanical properties compared with SiC/Ti3SiC2 composite. Especially, (TiB2+SiC)/Ti3SiC2 composite shows higher Young's modulus from 25 °C to high temperature and can retain a high modulus of 313 GPa (about 81% of room temperature value) up to 1200 °C. From 25 °C to 800 °C, (TiB2+SiC)/Ti3SiC2 composite has higher thermal conductivity and slightly lower coefficient of thermal expansion. Both water quenching test results and calculation of thermal shock resistance parameters, R, Rst and RIV indicate an improved thermal shock resistance of (TiB2+SiC)/Ti3SiC2 composite, with an increase of the critical thermal shock temperature difference ΔTc from 325 °C for SiC/Ti3SiC2 to 440 °C for (TiB2+SiC)/Ti3SiC2. Superior properties render (TiB2+SiC)/Ti3SiC2 composite a promising prospect as high temperature structural materials.