Orientation Dependence of Low Cycle Fatigue Properties of a Ni-based Single Crystal Superalloy DD10

Abstract Low cycle fatigue (LCF) properties of a nickel-based single crystal (SX) superalloy DD10 with different orientation deviation angles from the [001] axis were investigated at 760 °C with an invariable total strain amplitude of 1.4%. Results reveal that the LCF behaviors of DD10 exhibit a strong orientation-dependence. The fatigue life decreases apparently with the increment of the orientation deviation angle. For specimens with the same orientation deviation angle from the [001] axis, those on the [001]-[011] boundary exhibit a longer fatigue life than ones on the [001]-[ 1 ¯ 11] boundary. It is found that the orientation-dependence of fatigue life stems from the difference of accumulated plastic deformation per cycle. On the other hand, both of total stress amplitude and plastic strain amplitude show a reverse orientation-dependence compared with the fatigue life. However, the orientation deviation shows no influence on the model of fatigue crack initiation and subsequent propagation.