Abstract:In this paper, a Nickel-base single crystal superalloy was employed to study OP thermo-mechanical fatigue behavior by using scanning electron microscope (SEM), transmission electron microscope (TEM) and some other research methods. The main results are summarized as follows：A mean tensile stress was observed in OP TMF. With the mechanical amplitude increasing, the fatigue life decreases, whereas the stress range and the plastic strain increase. In the high temperature half cycle, the maximum compressive stress decreases during test, indicating a cyclic softening. The main mechanism for OP TMF is the formation of local slip bands in {111} planes. The interaction of creep, oxidation and fatigue damage lead to shorter life for TMF than isothermal fatigue. The fracture and propagation of slip bands is the main fracture style for OP TMF. The tensile stress is dominant factor affecting fatigue life in the test.
