In-situ fabrication and characterization of TiC matrix composite reinforced by SiC and Ti3SiC2

Owing to the poor self-diffusion coefficient of TiC, the mechanical and tribological properties of the TiC matrix composites were difficult to improve simultaneously by adding reinforcements. In this paper, the degradation of Ti3SiC2 was exploited as an advantage in obtaining the high-performance TiC matrix composites. The TiC matrix composites reinforced by SiC and Ti3SiC2 were in-situ fabricated by spark plasma sintering at 1400-1600 degrees C for 10 min. SiC and Ti3SiC2 were homogeneously distributed in the TiC matrix with well interfacial bonding with TiC matrix. The twin boundaries and stacking faults appeared in TiC particles. With the sintering temperature of 1500 degrees C, the TiC matrix composites exhibited excellent mechanical and tribological properties, which the bulk density, relative density, hardness, fracture toughness, and flexural strength reached the values of 4.76 g/cm3, 99.36%, 15.38 GPa, 5.38 MPa m1/2, and 562.3 MPa. The friction coefficient and wear rate of the TiC matrix composites sintered at 1500 degrees C reached the values of 0.48 and 3.04 x 10-9 mm3N-1m-1 at room temperature, and 0.55 and 6.63 x 10-9 mm3N-1m-1 at 500 degrees C, respectively. The wear mechanism of the TiC matrix composites was mainly ascribed to adhesive wear both at room temperature and 500 degrees C. A Fe-Si-oxide-Ti3SiC2 lubricating film was formed on the friction surface of the TiC matrix composites after a friction test at room temperature, while a Ti-Si-Fe-oxide lubricating film was formed after a friction test at 500 degrees C.