Improvement of the wear behavior of stircast Al–Si–Pb alloys by hot extrusion

The wear behavior of as-cast and hot extruded Al–Si–Pb alloys were investigated under dry conditions using a pin-on-disc type wear testing machine. The results show that the microstructure and mechanical properties can be greatly improved and porosity can be significantly decreased by hot extrusion. These factors contribute to great increase in wear resistance of hot extruded Al–Si–Pb alloys. Optical observation and X-ray photoelectron spectroscopy (XPS) analysis reveal the almost constant wear rate at mediate load levels. Better resistance to seizure for Al–Si–Pb alloys with more than 15 wt% lead 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.