Low Cycle Fatigue Properties of Nickel Base Single Crystal Superalloy at Different Temperatures

The low cycle fatigue properties of the Ni-Cr-Co-Mo-W-Ta-Nb-Re-Al-Hf-C series single crystal superalloy at different temperatures (800, 980℃) were studied. The results show that compared with those at 800℃, the plastic deformation of the alloy at 980℃ was greater, the damage was more serious, the fatigue strength was lower, and the life was shorter. The fatigue fractures of the alloys at two temperatures were cleavage-like fractures. At 800℃, the crack initiated at the loose microstructure and propagated along the 111 plane, and the instantaneous fracture area was relatively large. At 980℃, the crack initiated at the brittle oxide scale and propagated along the 001 plane perpendicular to the stress axis, and the instantaneous fracture area was relatively small.