BHM Berg- und Hüttenmännische Monatshefte

Moisture is often regarded as one of the main reasons for poor processability of powders using Laser-powder bed fusion (L-PBF) processes. To determine the influence of moisture on the spreadability, a superalloy powder IN718 commonly used for L‑PBF processes has been conditioned in two different states: once in the as-received and dry condition and once in a moist condition obtained by storing the powder for four weeks in an atmosphere containing a relative humidity of 75%. Using a self-built spreading tester and a subsequent analysis method specially developed for testing the spreadability of a powder, the differently conditioned IN718 powder batches have been investigated regarding the surface roughness and flatness of the powder layers. Additionally, the formation of empty spots between the powder particles in the top layer has been studied.