A model for simulation of recrystallization microstructure in single-crystal superalloy

Abstract

In the present investigation, a coupled crystal plasticity finite-element (CPFE) and cellular automaton (CA) model was developed to predict the microstructure of recrystallization in single-crystal (SX) Ni-based superalloy. The quasi-static compressive tests of [001] orientated SX DD6 superalloy were conducted on Gleeble3500 tester to calibrate the CPFE model based on crystal slip kinematics. The simulated stress–strain curve agrees well with the experimental results. Quantitative deformation amount was introduced in the deformed samples of simulation and experiment, and these samples were subsequently subjected to the standard solution heat treatment (SSHT). Results of CA simulation show that the recrystallization (RX) nucleation tends to occur at the third stage of SSHT process due to the high critical temperature of RX nucleation for the samples deformed at room temperature. The inhomogeneous RX grains gradually coarsen and compete to reach more stable status by reducing the system energy. Simulated RX grain density decreases from 7.500 to 1.875 mm−1, agreeing well with the value of 1.920 mm−1 from electron backscattered diffraction (EBSD) detection of the experimental sample.