INFLUENCE OF NOMINAL LAYER THICKNESS AT CLOSE VED VALUES ON THE POROSITY OF INCONEL 718 ALLOY MANUFACTURED BY LPBF METHOD
DOI:
https://doi.org/10.34185/1991-7848.itmm.2026.01.001Keywords:
LPBF, Inconel 718, volumetric energy density (VED), layer thickness, porosity, process performanceAbstract
The work investigated the effect of the nominal layer thickness on the formation of porosity in the Inconel 718 alloy manufactured by the laser powder bed melting (LPBF) method, provided that similar values of the specific volumetric energy density (VED) were provided. Two test specimens measuring 10×10×10 mm were manufactured with similar VED values (40.2 and 39.9 J/mm3), but different nominal layer thicknesses (40 and 60 μm). Metallographic analysis was performed on an optical microscope with subsequent quantitative assessment of porosity using the image analysis method (ImageJ). It was found that at similar VED values, the porosity level of the samples is comparable, however, differences in the pore size distribution are observed. For the sample with a larger layer thickness, the presence of single pores of larger size (up to 15-16 μm) was recorded, which may indicate an increased tendency to the formation of defects of the Lack of Fusion type. The obtained results confirm that the use of the VED indicator as the only criterion for process optimization is insufficient, since different combinations of parameters at close VED values can lead to differences in
defect morphology.
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