Temperature effect on the friction and wear of an Al-60Si alloy

This paper investigates the effect of environmental temperature on the friction and wear of an Al-60Si (Si >= 50%) alloy. The sliding tests were conducted on a pin-on-disk tribometer. The deformation mechanisms of the alloy under contact sliding were analysed by scanning electron microscopy and energy-dispersive X-ray spectroscopy. It was found that the friction coefficient increased, and the wear rate decreased with the rise of the environmental temperature. The severe subsurface deformation and fracture of silicon particles controlled the friction and wear mechanisms at room temperature. The wear modes were abrasion and delamination. However, at elevated temperatures, a mechanically mixed oxide layer containing materials from the disk formed in the wear tracks and dominated the wear mechanism. The thickness of the mixed layer increased, and wear mode changed from "adhesion" to "adhesion plus fracturing/ploughing of adhered materials" when the environmental temperature rose from 373 to 573 K. The surface oxidation facilitated the removal of the disk material leading to a higher wear resistance of the alloy.