Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7990036 | Journal of Alloys and Compounds | 2018 | 10 Pages |
Abstract
The γâ²/γ evolution in nickel superalloys under different stress states and stress values at 1223â¯K was simulated through the phase-field method to study the 45°-type rafting mechanism and the influence of orientation deviation on the γâ²/γ evolution. The simulation results demonstrate that for the shear stress case, 45°-type rafting appears under the external shear stress of 137â¯MPa. In 45°-type rafting, the equivalent stress inhomogeneity in the γ channel induces a directional diffusion of γâ²-forming elements into the low-equivalent-stress areas which are distributed along the diagonal directions. Based on the simulations, a model for the 45°-type rafting mechanism has been proposed. In addition, the influence of orientation deviation on γâ²/γ evolution originates from the introduction of shear stress components. With increasing external stress, the shear stress component is increased, which causes the rafting direction to approach the 45° direction. Furthermore, the existence of orientation deviation accelerates the process of γⲠrafting.
Related Topics
Physical Sciences and Engineering
Materials Science
Metals and Alloys
Authors
Min Yang, Jun Zhang, Hua Wei, Yan Zhao, Weimin Gui, Haijun Su, Tao Jin, Lin Liu,