Predicting the Low-cycle Fatigue Life of Additively Manufactured Nickel-Based Superalloys Using the Crystal Plasticity Finite Element Method

Unveiling the deformation mechanisms and life prediction of novel nickel-based superalloys fabricated by additive manufacturing (AM) is of paramount importance for their application in liquid rocket engines. In this study, the uniaxial tensile and cyclic stress-strain behaviors of a novel AM nickel-based superalloy were investigated using a crystal plasticity finite element (CPFEM) model. The simulation of uniaxial tensile behavior revealed a certain degree of plastic slip occurring intergranular, with the slip direction aligning with the macroscopic fracture direction. In the low-cycle fatigue behavior simulation, the accumulated plastic slip (APS) was incorporated into the fatigue indicator parameter (FIP) to predict the low-cycle fatigue life under two strain amplitudes. Compared to experimental data at strain amplitudes of 0.75% and 1%, the predicted fatigue life before failure is within a 2× scatter band. The research results of this article are beneficial for determining the low cycle fatigue life of new nickel-based superalloys produced by AM, and providing a theoretical basis for their future applications.