Influence of storage conditions and reconditioning of AlSi10Mg powder on the quality of parts produced by laser powder bed fusion (LPBF)

Abstract

Abstract The subject of this study is an investigation of the influence of storage conditions of AlSi10Mg powder on the LPBF parts. For this purpose, powders that were stored and aged under humid conditions in a climatic chamber for a certain period of time and subsequently dried in some instances were manufactured by LPBF. Afterwards, a comparison of the part density, mechanical properties and the surface quality of the LPBF parts was carried out. To gain a better understanding of the influences of the storage conditions considered on the powder and its behavior as feedstock, all aged powders were thoroughly characterized. A variation of the process parameters, laser power and scanning speed, were tested in order to identify the optimal parameter setting for the use of fresh, aged, and dried powder. It was found that the powders adsorb the water molecules in a mostly physical way. The natural oxide layer on the powder particles remains unaffected by the storage conditions. XPS investigations do not provide any clear evidence for the formation of hydroxides on the surface of the particles. Overall, the results of the printed parts show that the use of powder, which was stored under humid conditions, results in a lower part density and lower mechanical strength. This deterioration in processability can be reversed by drying the powder in a vacuum drying oven.