Tribological Behaviors of Ti3SiC2-Metal Composites Fabricated by Spark Plasma Sintering

Ti₃SiC₂/Cu, Ti₃SiC₂/Mo, Ti₃SiC₂/Ag and Ti₃SiC₂/Nb composites were fabricated by metallurgy/spark plasma sintering method. The phase composition and dry tribological behaviors of those composites were investigated and compared with those of pure Ti₃SiC₂. The results show that all additive metals could contribute to the decomposition of Ti₃SiC₂ to TiC, Si and TiSi composites. Mo and Cu will react with Si, producing Mo₅Si₃, (Ti_0.8Mo_0.2) Si₂, MoSi₂ and Cu₃Si, while Ag and Nb remain the form of element. All the composites exhibit improved tribological behaviors compared with pure Ti₃SiC₂. Among all the composites, the wear resistances of Ti₃SiC₂/Ag composite and Ti₃SiC₂/Nb composite are relatively better. The abrasive wear derived from pulling out and decoherence of grains is the main wear mechanism for Ti₃SiC₂and the composites. The hard phases of TiC and metal silicide in the composites play a fixation role in the friction, which prohibit the pullout and decoherence of grains and lead to low wear rates, however, the coexisted multiple phases in the composites lead to the reduction of bonding of grains, resulting in high wear rates. The presence of metal phases in the composites promotes intergranular reinforcement. In addition, material transference is another factor for high wear rates.