Influence of high current pulsed electron beam treatment on the tribological properties of Al–Si–Pb alloy

The tribological properties of Al–Si–Pb alloys irradiated by high current electron beam (HCPEB) were investigated under dry sliding conditions using a pin-on-disc type wear testing machine. The HCPEB parameters used to treat the samples are: electron energy: 21–25 keV; energy density: 1.5–2.5 J/cm2; pulse duration: 1.5 μs; number of pulses: 15. The results show that the microstructure and mechanical properties can be greatly improved. These factors contribute to great increase in wear resistance of HCPEB irradiated Al–Si–Pb alloys at 2.0 J/cm2 and 2.5 J/cm2. Optical observation and X-ray photoelectron spectroscopy (XPS) analysis reveal that the low wear rate and lowest level in coefficient of friction at high load levels for Al–Si–Pb alloys HCPEB irradiated with more than 1.5 J/cm2 are due to a film of lubricant covering almost the entire worn surface. This film is a mixture of different constituents containing Al, Fe, Si, O and Pb, in which Pb exists in the form of Pb4SiO6. With the applied load increased, the dominant wear modes exhibit successively the oxidative wear, film spalling, and adhesive wear.