Influences of Process Parameters and Addition Elements on the Fabrication of TiC-Ti₃SiC₂ Composites by Spark Sintering

Abstract

In TiC-Ti₃SiC₂ composites, the introduction of the TiC hard phase could improve the hardness of the Ti₃SiC₂ phase and prepare high hardness, high toughness and self-lubricating materials. In this study, elementary Ti, Si and graphite powders in the molar ratio of 3:1+x:2 were used as starting powders, a small amount of Al powder was added as a sintering aid, and spark sintering technology was used to sinter in the temperature range of 1373 to 1673 K at 50 MPa in vacuum. The reacted phases were identified by X-ray diffraction, and microstructure characteristics were observed. The formation mechanism of TiC-Ti₃SiC₂ composites was investigated based on the sintering behavior of the elemental powders during spark sintering. Pure TiC-Ti₃SiC₂ composites could be prepared from Ti, Si, graphite powders and Al at a molar ratio of 3:1.1:2:0.3 at 1573 K with a holding time of 0.9 ks. In conclusion, dual phase consist of TiC and Ti₃SiC₂ composite could be synthesized through in-situ reaction by adjusting process parameters such as sintering temperature, holding time and the content of Si and Al in element blending method.