Three-dimensional elastoplastic phase-field simulation of γ′ rafting and creep deformation

A modified phase-field model coupling viscoplastic constitutive equations has been built up to simulate the creep process of nickel-base single-crystal superalloys at 1223 K/300 MPa. The kinematic and isotropic hardening effects as well as interactions of slip systems are included in the present model. Under the external tension along [001] direction, the plastic strain prefers to concentrate in the channel vertical to [001] direction, promoting γ′ precipitate to raft along the direction vertical to [001] direction. The interactions between slip systems alter the value of plastic strain and thus the stress field in inner γ channel. In turn, the stress field readjusts the plastic deformation. The simulative results and experimental data are in good agreement in the initial creep stage. In addition, this modified model gives a possibility to simulate the microstructure evolution during cycle fatigue.