Abstract: The fretting wear characteristics of GCr15/TC4 alloy pairs under mixed slip state in air medium and pure water environment were investigated by SRV-IV fretting wear tester. Three-dimensional morphology, wear volume, wear surface morphology, friction coefficient curve and fretting diagram were characterized by laser confocal microscope and scanning electron microscope to explore the fretting wear mechanism of TC4 alloy under mixed slip state in different environmental media. The results show that the change trend of friction coefficient curve in three media is basically the same. Under the condition of dry friction, the friction coefficient of air environment at 25 ℃ is high and fluctuates greatly, the wear volume is the largest, and the wear mechanism is mainly adhesive wear and slight oxidation wear. In 300 ℃ atmosphere environment, the friction coefficient and fluctuation degree are the smallest. High temperature and friction heat accelerate the oxidation of abrasive particles. The formation of the third body reveals that TC4 alloy has high temperature wear resistance, and the wear mechanism is adhesive wear and oxidation wear. Compared with dry friction, the friction coefficient, fluctuation degree and wear rate in water-covered environment are between them. Water medium plays a role in lubrication and antifriction, and the wear mechanism is abrasive wear.

Key words: TC4 alloy, fretting wear, environmental medium, friction oxide