Creep Simulation of Laser Powder Bed Fused Inconel 718: Performance Evaluation of Material Constitutive Models

ABSTRACT

Creep deformation limits the high‐temperature use of Inconel 718 components fabricated by laser powder bed fusion (LPBF), affecting safety and maintenance risks. The LPBF process introduces microstructural heterogeneities and anisotropy, making accurate creep prediction challenging. Experimental creep testing can be costly and time‐intensive, highlighting the need for accurate numerical simulations based on effective models. Selecting an appropriate model is crucial, as prior studies have shown the effectiveness of various models in predicting creep behavior. This study aims to evaluate the power law, hyperbolic‐sine, and six‐theta models under different uniaxial stresses (550, 650, 750, and 850 MPa) and temperatures (650°C and 700°C) for LPBF‐fabricated Inconel 718 components using finite element analysis. The results revealed that the power law and hyperbolic sine models showed limited capability in representing the anisotropic and heterogeneous creep response. ANOVA across creep stages confirmed that the six‐theta model reduces prediction error by 20%–30% compared to alternatives, and it demonstrated superior performance in predicting primary creep and subsequent creep rate under all conditions. The six‐theta model outperforming power law and hyperbolic‐sine models. The power law model did not account for the tertiary stage and rupture time, while the hyperbolic‐sine model failed to capture the primary stage.