A novel creep model with synergetic Orowan bypassing and climbing mechanisms in nickel-base superalloys

Abstract

A novel creep model was proposed to accurately and conveniently predict the steady-state creep rate of precipitation-strengthening nickel-base superalloys. Based on the space distribution of precipitates, the synergetic mode of Orowan bypassing and dislocation climbing mechanisms in dislocation–precipitate interaction was coupled into the new creep model according to probability–correlative method. The results show that the new model can accurately describe the steady-state creep rate compared with the experimental data, which is far better than the classical model. Moreover, the present model no longer relies on the adjustable parameters. The quantitative relationship between threshold stress and temperature is also determined. This work sheds new light on the dislocation–precipitate interaction during creep deformation, and provides an effective model for designing precipitation-strengthening alloys with improved creep properties.