High-Temperature Tangential Fretting Wear Behaviour of 2A70 Aluminum Alloy

High temperature is a key factor affecting the service life of centrifugal impellers. In this paper, 2A70 aluminum alloy, a centrifugal impeller material was selected as the research object, and the fretting wear characteristics of 2A70 aluminum alloy at different temperatures (25, 100, 175, 250 ℃) were studied. The micro-morphology, tribological chemical state and main damage mechanism of the fretting wear in the slip regime (50 μm) were mainly discussed. The result demonstrated that in the same load and displacement conditions, the fretting regime was not modified by raising the temperature, but it had a significant influence on the friction coefficient, frictional dissipation energy and fretting wear mechanism. In the high temperature conditions, the material damage degree of 2A70 aluminum alloy was higher than that in the room temperature, the fretting wear mechanism included abrasive wear, adhesive wear and oxidative wear. With temperature increasing, the friction coefficient and wear volume ascended at first and then descended with increasing temperature. When the temperatures reached 100 and 175 ℃, due to the influence of high temperature thermal softening, the deformation resistance of the material was reduced and the fretting damage was intensified. When the temperature reached 250 ℃, the oxide debris layer could form at a lower number of cycles, reducing the contact area between friction pair and alleviating the material abrasion.