The strain-controlled fatigue behavior and modeling of Haynes® HASTELLOY® C-2000® superalloy

The strain-controlled fatigue behavior of the new nickel–chromium–molybdenum superalloy, HASTELLOY® C-2000® was investigated. Low-cycle fatigue specimens were tested in strain-controlled fatigue conditions under axial strain range control at 24 °C, 204 °C and 427 °C. The results indicated that at total strain ranges below 0.8%, temperature does not significantly influence fatigue life, whereas at high total strain ranges, there is a significant drop in fatigue life at 427 °C. At room temperature and 204 °C, the cyclic stress response was cyclic hardening, followed by cyclic stability, cyclic hardening, or cyclic softening, depending on the total strain range. At 427 °C, only cyclic hardening was observed. Fractographic and metallographic analyses were also conducted. The strain–life and Holloman relation parameters are calculated. A theoretical model that predicts the life of this alloy under the tested conditions using the plastic strain energy method is also presented. The results of the theoretical model are in good agreement with the experimental results.