An experimental investigation on fretting wear behavior of copper - magnesium alloy

The fretting wear behavior of copper-magnesium alloy (Cu-Mg alloy) used for high-speed railway catenary system was investigated. Fretting tests of Cu-Mg alloy cylinder against Cu-Mg alloy cylinder at vertical cross contact configuration were carried out on a fretting wear rig at room temperature. The running condition fretting map (RCFM) composed of partial slip regime (PSR), gross slip regime (GSR), and mixed fretting regime (MFR) was constructed depending on different normal loads and displacement amplitudes. In PSR, only slight surface damage was detected on the wear scar. In MFR, the morphologies of the wear scar displayed a clear subdivision in the central stick zone and the surrounding annular slip zone. Fatigue cracks initiated and propagated at the boundary between the stick zone and slip zone. The damage mechanism is the combination of fretting fatigue and fretting wear which combines adhesion, surface fatigue and slight tribochemical reactions. In GSR, fretting wear is predominant. The wear mechanisms were mainly abrasion, surface fatigue and severe tribochemical reactions dominated by oxidation.