Effects of SiC amount on phase compositions and properties of Ti₃SiC₂-based composites

Abstract

The phase compositions and properties of Ti₃SiC₂-based composites with SiC addition of 5%–30% in mass fraction fabricated by in-situ reaction and hot pressing sintering were studied. SiC addition effectively prevented TiC synthesis but facilitated SiC synthesis. The Ti₃SiC₂/TiC-SiC composite had better oxidation resistance when SiC added quantity reached 20% but poorer oxidation resistance with SiC addition under 15% than Ti₃SiC₂/TiC composite at higher temperatures. There were more than half of the original SiC and a few Ti₃SiC₂ remaining in Ti₃SiC₂/TiC-SiC with 20% SiC addition, but all constituents in Ti₃Si₂/TiC composite were oxidized after 12 h in air at 1500 °C. The oxidation scale thickness of TS30, 1505.78 μm, was near a half of that of T, 2715 μm, at 1500 °C for 20 h. Ti₃SiC₂/TiC composite had a flexural strength of 474 MPa, which was surpassed by Ti₃SiC₂/TiC-SiC composites when SiC added amount reached 15%. The strength reached the peak of 518 MPa at 20% SiC added amount.