Productivity-oriented SLM process parameters effect on the fatigue strength of Inconel 718

Impact of process parameters on the dynamic behavior of Inconel 718 fabricated via laser powder bed fusion

“…The process parameters used to print the specimens were chosen on the basis of an extension of the Rosenthal solution [40,61,62], which describes the thermal field produced in L-PBF processes. The formulation, proposed by Moda [25], was validated by Macoretta et al [44], who demonstrated that process parameters belonging to the so-defined L-PBF feasible region produce a material not affected by macroscopic metallurgical defects, and having only a slight reduction in the fatigue strength. The adopted formulation correlates the main process parameters (laser power, scan speed, hatch distance, layer thickness) and the material thermal properties through two dimensionless parameters, namely the normalized speed V * and power P * .…”

“…3 L-PBF process feasible region (white hatched region). Literature data and A 2 , A 3 , and A 5 are obtained from [25,44] The final process parameter combinations adopted in the present work are an extension of those used in [44] and were determined starting from the baseline values suggested by Renishaw and already investigated in other studies [37,43] (hereafter defined as Baseline). The remaining combinations were obtained within the feasible region by moving along a straight line having a similar margin with respect to the lack of fusion (LoF) region (hereafter defined as A i ).…”

“…It can be noticed that, at the lowest energy density, the process build rate can reach a 150% increase compared to the Baseline case. Compared to [44], which adopted only the A 2 , A 3 , and A 5 parameters, the higher number of combinations adopted allows to analyze in detail the effect of the process parameters on the dynamic properties of the material.…”

“…Simonelli [41] and Bertolini [42] analyzed the effects of printing direction on the mechanical properties and anisotropic behavior of different printed materials. Other studies characterized the fatigue resistance and the propagation of cracks as a function of the process parameters [43,44] and the build orientation [45][46][47].…”

Recent developments and future trends in fatigue life assessment of additively manufactured metals with particular emphasis on machine learning modeling

“…Ghorbanpour et al 86 obtained SLM IN718 material with finer grains by increasing P, introducing differently oriented less favorable slip systems and improving short crack growth resistance. Ciampaglia et al 87 employed an ML method to analyze the sensitivity of AM AlSi10Mg process parameters and found that the fatigue properties of the material were negatively correlated to h and d. Macoretta et al 88 developed two new sets of process parameters based on the standard set of parameters by increasing v and h with the aim of improving the productivity and prepared SLM IN718 specimens for the evaluation of static and fatigue properties. The results show that although the change in process parameters introduces a large number of directional LoF defects and a 120% increase in surface roughness height, the fatigue strength of the material is only reduced by 5%, the hardness of the material is slightly increased, and the productivity is significantly increased by 50%, highlighting the importance of tailoring the AM parameters to the target performance or economy.…”