Multi-Scale Simulation of GH4706 Superalloy Turbine Disk Prepared by Integral Hot Forming

During hot deformation of GH4706 alloy forgings, to achieve effective control over the uniformity of its microstructure, it is first necessary to establish a quantitative relationship between the microstructural characteristics of an entire hot-formed turbine disk forging and process parameters using reliable methods. Based on hot compression test results of GH4706 alloy at temperatures ranging from 950 °C to 1150 °C and strain rates from 0.001 s−1 to 1 s−1, this study developed a microstructure evolution model. Multi-scale high-precision numerical simulations were performed to predict the parameter field distribution and microstructure distribution of the turbine disk. The results reveal that the inhomogeneity of strain distribution is the primary cause of mixed grain formation. Statistical comparisons between simulation predictions at six validation points and industrial experimental data revealed the following relative deviations: 5.21% for average grain size (AVG), 9.65% for the standard deviation of grain size distribution (SD), and 5.31% for DRX fraction. Additionally, the standard deviations of prediction error for these three parameters are 3.26% for AVG, 4.06% for SD, and 3.12% for DRX fraction. These results demonstrate that the multi-scale dynamic recrystallization model developed in this study exhibits satisfactory prediction accuracy and stability. The modeling approach presented in this paper is of great significance for precisely controlling the uniformity of microstructural distribution during the hot deformation of GH4706 alloy.