Advanced Materials for Applications at High Temperature: Fatigue Assessment by Means of Local Strain Energy Density

The interest on fatigue assessment of steel and other alloys at high temperature has increased continuously in the last years. However, high cycle fatigue of notched components at high temperature has not been deeply investigated experimentally and theoretically. The present paper investigates the accuracy of Strain Energy Density (SED) averaged over a control volume approach when applied to high-temperature fatigue data from notched components. In the present work, a large bulk of high-temperature fatigue data, taken from the literature and regarding notched components made of different advanced materials, is reanalyzed. In detail: C45 carbon steel at 250°C, Inconel 718 at 500°C, and directionally solidified superalloy DZ125 at 850°C are considered. The main advantage of SED averaged over a control volume is that different geometries can be summarized in a single narrow scatter band. From an industrial viewpoint, the use of a geometry-independent parameter (and fatigue curve) leads to a considerable advantage in terms of time and cost.