Effect of Stress on Creep Behavior of Single Crystal Alloy IC6SX at 980°C

Ni3Al-based single crystal alloy IC6SX was prepared by seed crystal method. The effect of different stress conditions on creep behavior of this alloy at 980 degrees C was investigated. The results showed that the creep life of this alloy at 980 degrees C decreased significantly with the increase of stress. When the stress increased from 180 MPa to 230 MPa, the creep life dropped from 245.5 h to 69.3 h, and the steady-state creep rate increased slightly but not significantly. Meanwhile, the morphology of gamma ' phase and dislocation after creep were studied. The results showed that with the increase of stress, the density of dislocations in the gamma ' phase increased gradually, the strength of this alloy decreased gradually, so the creep life decreased significantly. The Y-NiMo phase resolved from the gamma phase decreased gradually as the creep life decreased. The creep experiment of the alloy was carried out at 980 degrees C. Due to the higher temperature, the diffusion of atoms in this alloy became faster. Deformation was not only caused by the slippage of dislocations in the crystal but also by the diffusion of atoms. Therefore, the creep mechanism of single crystal alloy IC6SX at this temperature is a mixed mechanism of dislocation glide and diffusion.