Oxidative Damage of a Superalloy in High-Loaded Contacts

Abstract

When used as a turbine material, dry contacts of nickel-based superalloy experience stresses via pressure and temperature. As a result, there is a change in material in the form of oxide layer formation and a depletion of alloying elements (e.g., Al) in the base material. The resulting layers have different material properties compared to the base material, which affect the mechanical and contact behavior. Adhesion, friction and wear are among the effects that are of interest. In addition, the operating experience has shown that the contact pressure has a yet unclarified impact on the progression rate of the damage process (oxidation). This paper deals with the development of models that contribute to the understanding of the damage scenario and its prediction. We will see that the changed material properies in the oxid layer lead to high-stress peaks at the interface between the layers. This is the expected location were the accelerated damage occures.