Fatigue Characterization and Modeling of Additively Manufactured Hastelloy-X Superalloy

Tensile and High Cycle Fatigue Performance at Room and Elevated Temperatures of Laser Powder Bed Fusion Manufactured Hastelloy X

“…They established a correlation between the fatigue life of LPBF-built Hastelloy X and the process parameters, suggesting that crack initiation occurs earlier due to the higher stress concentration caused by deeper surface valleys at high laser scanning speeds. Esmaeilizadeh et al [11] further investigated the cyclic deformation and fatigue behavior of LPBF-built Hastelloy X under various strain amplitudes and employed different fatigue models to predict its fatigue life. Palm et al [12] evaluated the effects of lack of fusion (LOF) defects on the mechanical properties and fatigue properties of LPBF-built Hastelloy X through tensile and high cycle fatigue (HCF) tests, indicating that the defects would significantly reduce the HCF performance of the specimen.…”

Microstructure sensitive fatigue life prediction model for SLM fabricated Hastelloy-X

“…This worse fatigue performance of SLM components, particularly in as-built case, has been attributed to the porosity [17], surface roughness [18] or residual stresses [19], and also to the resulting anisotropy of the part and its orientation with respect to the cyclic loading direction [19,15]. However, some studies reported the mitigation methodologies for porosity, surface roughness and residual stresses effects on the fatigue lives by optimizing the processing parameters [20], heat treatment [21] and powder composition [3]. With respect to the specimen orientation, the fatigue life of vertically built specimens has been found to be inferior to horizontally built parts when loaded under stress control [22,16,12,23,19].…”

“…From the modelling view point, empirical models such as Basquin, Coffin Manson, etc., have been used with experimental data to correlate the fatigue life of different additive manufactured alloys [27,28,29], including the study of SLM Hastelloy-X by Esmaelizadeh et al [20]. However, it is well known that there is a strong influence of the microstructure in the fatigue life of an alloy, and these models cannot account for it because they are empirical and calibrated with experimental data without considering any microstructural aspect.…”

“…In some cases the life prediction is focused on crack propagation [47] stage. Other studies consider crack nucleation but the life prediction model is directly linked with the macroscopic cyclic response [25,20,27], without making use of the distribution of microscopic fields obtained. Only a few studies on AM alloys are available which rely on the use of micromechanical fields through fatigue indicator parameters (FIPs) to estimate the fatigue life assuming crack nucleation controlled fatigue.…”