Tribological Performance of Ni3Al Matrix Self-Lubricating Composites Containing Multilayer Graphene and Ti3SiC2 at Elevated Temperatures

The application of Ni3Al-based alloy (NA) in the field of aerospace was limited by its poor tribological properties. For improving the tribological performance of NA, multilayer graphene (MLG) and Ti3SiC2 were added in Ni3Al matrix composites. Tribological behavior of Ni3Al matrix composites containing 1.5 wt.% MLG and 10 wt.% Ti3SiC2 (NMT) against Si3N4 ball at 12 N-0.2 m/s from 25 to 750 A degrees C was investigated. The results showed that NMT exhibited the excellent tribological behavior [lower friction coefficients (0.26-0.57) and less wear resistance (3.1-6.5 x 10(-6) mm(3) N-1 m(-1))] due to synergetic effect of MLG and Ti3SiC2 over a wide temperature range from 25 to 750 A degrees C. At 25-350 A degrees C, part of MLG enriched on worn surface could play a role in reducing friction and improving wear resistance. At 350-550 A degrees C, although MLG gradually lost the lubricating properties, the partial decomposition of Ti3SiC2 could continually improve the tribological properties of NMT. At 550-750 A degrees C, Ti3SiC2 on worn surface was oxidized to form lubricating film, while Ti3SiC2 in the subsurface played an important role in supporting the film, resulting in the excellent high-temperature tribological performance. The research had good guiding significance for the preparation of wide temperature range self-lubricating material and the study of synergetic effect of complex solid lubricants.