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

Abstract

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.