The microstructure characteristics and self-lubrication mechanism of the NiAl matrix composites prepared by vacuum hot-pressing sintering

NiAl–Ti₃AlC₂ and NiAl–Mo₂TiAlC₂ composites were fabricated in-situ using a vacuum hot-pressing sintering technique. The microstructure and high temperature tribological performance of the composites were studied. When compared with NiAl–Ti₃AlC₂ composite, the NiAl–Mo₂TiAlC₂ composite contained the Mo₂TiAlC₂ precipitated phases and some nano-precipitated phases of Mo₂TiAlC₂ distributed along the grain boundaries. Meanwhile, the high temperature tribological property of NiAl–Mo₂TiAlC₂ composite was more superior than that of NiAl–Ti₃AlC₂ composite. The worn surface of NiAl–Mo₂TiAlC₂ composite formed a dense and continuous lubricating layer of MoO₃ when subjected to the friction test at 800 °C, which could effectively improve the overall tribological properties of the composites.