A novel creep model with synergetic Orowan by passing and climbing mechanisms in nickel-base superalloys
(1. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China;
2. Light Alloy Research Institute, Central South University, Changsha 410083, China;
3. State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, College of Mechanical and Vehicle Engineering, Hunan University, Changsha 410082, China)
2. Light Alloy Research Institute, Central South University, Changsha 410083, China;
3. State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, College of Mechanical and Vehicle Engineering, Hunan University, Changsha 410082, China)
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.
Key words: nickel-base superalloys; creep model; steady-state creep rate; threshold stress