Phase-Field Simulation of γ"(D022) Precipitation in Ni Base Superalloys
Although the γ"(D022) phase has been known as a strengthen phase for the turbine disk of wrought Ni-base superalloys, the computer simulation of the γ"(D022) precipitation is hardly performed. In this study, it is demonstrated that the phase-field modeling of the complex microstructure developments including γ"(D022) precipitation in Ni-V-X (X=Co,Nb,Fe) alloys. The simulation results obtained are as follows: (1) The complex morphologies of the γ(A1)+γ"(D022) two-phase microstructure, such as the maze-microstructure, the chessboard-microstructure, and the chessboard-like microstructure, in Ni-V-X (X=Co,Nb,Fe) alloys are simulated reasonably by using phase-field method. (2) The morphology of the microstructure is mainly controlled by the elastic strain energy induced from the lattice mismatch. In particular, the tetragonal distortion is a key parameter to control and understand the complex microstructure changes.
Young Won Chang, Nack J. Kim and Chong Soo Lee
T. Koyama and H. Onodera, "Phase-Field Simulation of γ"(D022) Precipitation in Ni Base Superalloys", Materials Science Forum, Vols. 561-565, pp. 2287-2292, 2007