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This work follows up on the influence of the processing parameters and a subsequent heat treatment on the resulting properties of magnetizable neodymium-iron-boron (NdFeB) parts produced by Laser Powder Bed Fusion. Highly dense (> 95 %) cubes were built up and an uneven distribution of neodymium- and iron-rich phases was observed. It could be shown that internal stresses leading to crack development represent the main challenge. According to the experimental results, this can be approached more effectively through successive optimization of the processing parameters and therefore adjustment of the energy input rather than heat treatment of the built parts.

The PBF-LB/M (laser-based powder bed fusion of metals) process is associated with high as-built surface roughness and surface texturing caused by a variety of process inherent effects. It is well known that surface roughness is influenced by the applied processing parameters and correlates with porosity. In terms of reactive materials like Ti-6Al-4V, also the powder recycling grade and especially the residual oxygen content within the processing atmosphere play important roles regarding process stability, reproducibility and part properties. Therefore, this study investigated the influence of the residual oxygen content on porosity and surface roughness for virgin as well as recycled powder by employing DoE techniques. Within the examined range, unlike for the roughness, no significant influence of residual oxygen content and powder constitution on porosity could be detected. It could be shown that the reproducibility of relative density mainly depends on the processing parameter combination. Furthermore, powder recycling led to higher top and side surface roughness and a dependence of surface texture on processing parameters could be demonstrated.

In laser-based powder bed fusion of metals (PBF-LB/M) the presence of oxygen is known to encourage embrittlement and impair the wetting properties of the substrate and solidified material. Conventionally, inert gases like argon are used to reduce the residual oxygen content within the processing atmosphere. However, especially in terms of reactive materials like titanium the remaining oxygen still causes critical oxidations.In this publication, a new approach for obtaining an oxygen-free processing atmosphere is presented. Thereby the argon shielding gas is doped with reactive monosilane to reduce the residual oxygen content to a range comparable to XHV (Extreme High Vacuum, thermodynamic oxygen activity