LCF life prediction of turbine disc alloy using crystal plasticity and 3D representative volume element containing twin boundaries

The traditional LCF life prediction method based on macroscopic behavior is difficult to reveal the microscopic fatigue failure mechanism. Therefore, the crystal plasticity finite element method and the representative volume elements considering the real microstructure were used to simulate the cyclic deformation of a nickel-based superalloy FGH4098, and a fatigue failure criterion is established to predict the LCF life. The influence of twin boundary on the prediction accuracy is particularly discussed. Meanwhile, the hotspots which are potential sites for fatigue crack initiation were analyzed. The results show that the consideration of twin boundary can improve the accuracy of life prediction, with a scatter factor of +/- 1.3 only.