Fretting Fatigue Life Extension for Single Crystal Ni-Based Superalloy by Applying Optimized Surface Texturing

Abstract

Fretting fatigue (FF) lives of the CMSX-4 single crystal alloy have been measured, via some different counterpart materials in similar and dissimilar material combinations at room and elevated temperatures. The CMSX-4 specimens were machined so that the [001] crystallographic orientation was within 5° along the longitudinal axis of the SC specimen. In this work, the work special attention was paid to find some useful methods to extend the FF lives by controlling the surface texture of contacting pad, as well as to get the metallurgical and mechanical aspects in the FF damage. The experimental works demonstrated that the texturing was effective to improve the FF lives. The stress field equations along the contacting interface have also been derived employing contact mechanics theories so that the FF lives and the failure characteristics can be rationally estimated, on the basis of mechanical backgrounds. A new method proposed successfully provided reasonable predictions in agreement with the experimental results.