Friction and wear behavior of copper metal matrix composites at temperatures up to 800 °C

Abstract

High Temperature may exert a great impact on the service life and reliability of friction materials during friction sliding. Tribological behavior of a new developed copper metal matrix composite (Cu-MMC) against a steel disc was investigated using a home-built pin-on-disc tribometer in the ambient temperature range of 25–800 °C. Detailed analyses of worn surfaces and subsurfaces were performed using scanning electron microscope, optical microscope, X-ray diffractometer and 3D optical profiler. The worn surface of Cu-MMC exhibited different features at various ambient temperatures, resulting in a significant difference in tribological properties. The friction coefficient increased slightly from 0.563 to 0.640 as the ambient temperature varied from 25 °C to 400 °C, then a further increase in the ambient temperature led to a sharp decrease in the friction coefficient to 0.323 at 800 °C. A prompt increase in the mass loss of Cu-MMC was evident with increasing the ambient temperature from 25 °C to 400 °C, and then a slight increase occurred in mass loss of Cu-MMC upon increasing the ambient temperature up to 600 °C after which a significant declining trend of Cu-MMC was observed. The worn surfaces with a rugged and fluctuant morphology contributed to the high and unstable friction coefficient, as well as the high mass loss of Cu-MMC. The dominant wear mechanisms of Cu-MMC were severe oxidation, abrasive wear and adhesive wear at 400 °C and 600 °C, then delamination wear and oxidation at 800 °C.

Keywords

• Metal matrix composites
• Friction coefficient
• Wear mechanism
• High temperature
• Powder metallurgy