A thickness-sensitive and orientation-related creep lifetime prediction method of nickel-based single crystal superalloy

Considering the anisotropy of nickel-based single crystal superalloy, an anisotropic creep lifetime prediction model based on slip plane damage is developed. The predicted results indicate that the lifetime prediction model could predict the creep lifetimes of nickel-based single crystal superalloy with different orientations accurately. Furthermore, in order to reveal the damage mechanism of nickel-based single crystal thin-walled specimen, creep experiment and failure analysis of thin-walled specimen are conducted, and there are obvious differences in damage mechanisms between surface and interior of the thin-walled specimen. In this paper, both thickness debit effect and abnormal thickness debit effect are considered to be caused by the damage differences between surface and interior of the thin-walled specimen, and zone-based failure criteria considering thickness debit effect and abnormal thickness debit effect are proposed. Finally, combining the anisotropic creep lifetime prediction model and zone-based failure criteria, the creep lifetime prediction of DD6 specimen with different thickness is conducted. The predicted lifetimes are within a scatter band of factor 2.26, and the predicted laws between creep lifetimes and thicknesses of the specimens are in good agreement with the experimental results, which verifies the rationality and accuracy of the thickness-sensitive creep lifetime prediction method established in this paper.