Tribological properties of in situ Fe₃Al-20 wt% Al ₂O₃ composites

The tribological properties of Fe₃Al-20 wt% Al₂O ₃ composites, prepared by means of mechanical alloying and plasmaactivated sintering, were investigated under air atmosphere against GCr15 bearing steels from room temperature to 500 °C. It was found that the friction coefficient of the composites (at 200 °C/350 °C) decreased with increasing temperature and the value was lower than that of Fe₃Al alloys at the same temperature, and the friction coefficient increased again at 500 °C. Moreover, the wear rates of all the pins and discs were low at the medium/high temperatures. The dominant wear mechanism of the composites is microplowing and a little oxidation wear at room temperature. However, at elevated temperatures, oxidation wear and a little microplowing are found to be the main wear mechanism. There is also spalling induced by microfracture at 500 °C. The in situ Fe₃Al-20 wt% Al₂O₃ composites have excellent wear resistance at a wide temperature range.