Influence of Surface Treatments on Fretting Fatigue of Ti-6242 at Elevated Temperatures

摘要

Where fretting fatigue of titanium alloy gas turbine engine component is concerned, the effect of temperature on fretting processes can be quite significant. Service exposed third stage compressor blades, operating at 454deg C or 850 deg F, showed severe signs of fretting, wear, CuNiIn coating delamination, oxidation and pitting on the dovetail pressure surfaces. Under cyclic loading conditions fretting fatigue cracks, initiated in these damaged areas, can cause dramatic reduction in fatigue life of these components leading to potential catastrophic failure. A study has been carried out to evaluate the influence of various surface treatments, such as ion treatments, coatings and shot peening, on the fretting fatigue life of titanium alloy gas turbine engine components at elevated temperature. Results from high temperature fretting fatigue and pin-on-disk wear tests are discussed in this paper. Significant contrast between the wear and fatigue test results illustrates the potential dangers of using sliding wear tests to rank surface treatments for fretting fatigue amelioration.