Fretting Fatigue of Nickel Based Superalloys at Elevated Temperature

Experiments are conducted to characterize the fretting fatigue behavior of advanced nickel based alloys common to turbine disk and blade applications. The experiments ad-dress the effects of different materials, loading types, and surface treatments. Block loading experiments show that minor cycles reduce fretting fatigue life. Accurate friction coefficient data necessary to develop fretting fatigue life prediction is also reported. Background Fretting refers to the small scale relative tangential motion that occurs at the edge of nominally clamped contacts subjected to oscillatory loading. The formation and propagation of cracks in the presence of fretting induced stresses is known as fretting fatigue. Blade/disk attachments in gas turbine engines are susceptible to fretting fatigue. This paper describes experiments that characterize fretting fatigue in advanced nickel based alloys subjected to contact stresses similar to those that occur at blade/disk contacts. The experimental apparatus used for these experiments has been described elsewhere.1 A schematic defining the applied loads is given in Figure 1. The experiments are designed to address the influence of different loading types, surface treatments, contact geometries, and contact materials on the fretting fatigue performance of advanced nickel base