Effect of Temperature on Fretting Wear Behavior of DD6/GH738 Alloys

To investigate the evolution rule of fretting wear behavior of nickel-based superalloys for aero-engine high-temperature components, the influence law and mechanism of temperature (20~750 ℃) on the fretting wear characteristics of DD6/GH738 friction pair, the typical material of turbine tenon joint structure, were systematically studied. Line contact fretting wear tests were carried out at different temperatures with a friction testing machine. In addition, friction coefficient analysis, three-dimensional morphology characterization, and microscopic analysis were conducted to reveal the effect mechanism of temperature on the friction characteristics and damage behavior. The results demonstrate that with the temperature rising, the friction coefficient decreases from 1.50 at 20 ℃ to 0.35 at 750 ℃, accompanied by a transition in fretting behavior from mixed slip to gross slip. The wear mechanism exhibits significant temperature dependence: adhesive wear is dominant at 20 ℃, with the minimal wear volume of 0.009 mm³; abrasive wear intensifies at 400 ℃, and the wear volume increases to 0.028 mm³; the dense enamel third-body layer due to oxidation at 750 ℃ significantly inhibits substrate damage, and the wear volume is reduced to 0.004 mm³. The third-body lubrication effect induced by oxidation at 750 ℃ is a key factor for reducing the friction coefficient and wear rate.