Effects of Graded Powder Dosage Factors on the Densification of LPBF Processed Inconel 718

Abstract

The present work offers insights into real-time powder management (graded powder dosage factor) and its effects on the densification behaviour of the 3D parts fabricated using the laser powder bed fusion (LPBF) technology. Inconel718 samples were printed using three different powder dosages in a graded manner (higher to lower along the build direction) at various locations on the build platform. The porosities of printed samples with different powder dosages were evaluated using an optical microscope. The porosities were categorised into two variants, viz.

inter-micropore and super-micropore. The inter-micropores were higher than the super-micropores at all locations under the graded powder dosages scheme. Moreover, the overall porosities were marginally lower at a build platform's R1, C1 and L1 locations than others (L2 and R2). Therefore, preferable locations while LPBF processing arrived by reinforcing the effective graded powder dosage scheme enabling cost-efficient LPBF processing strategies. This study enables the printing of moderate-sized functional prototypes uninterruptedly and without sacrificing the quality of virgin feedstock powder. © 2023, The Indian Institute of Metals - IIM.