High nitrogen steels produced by laser powder bed fusion – Processability of an additivated austenitic steel powder

The additivation of conventional metal powders allows the expansion of the range of materials and alloys suitable for powder bed fusion additive manufacturing of metals. The combination of material properties, the improvement of currently used powder properties, and their processability are the focus of this technique. This work investigates the influence of the additivation of Si 3 N 4 particles to X2CrNi18–9 austenitic stainless-steel powder on the resulting powder properties and processability by PBF-LB/M. The aim is to process a composite material consisting of a steel matrix in which retained Si 3 N 4 particles are embedded. A subsequent heat treatment by hot isostatic pressing should allow dissociation of Si 3 N 4 and the associated nitrogen diffusion into the austenitic matrix to produce a high nitrogen steel (HNS). Despite some degradation in powder properties, as indicated by a decrease in the Hausner ratio from 1.24 to 1.15, PBF-LB/M successfully produced samples in a process window of 30–36 J/mm 3 . • The flow rate, Hausner-Ratio, and packing density are adversely affected by a Si 3 N 4 additivation. • Si 3 N 4 particle additivation does not affect the reflectance of X2CrNi18–9 powder at a wavelength of 1070 nm. • Processability of Si 3 N 4 -additivated X2CrNi18–9 powder via PBF-LB/M is reduced, leading to inhomogeneous defects.