Role of powder particle size on laser powder bed fusion processability of AlSi10mg alloy

Abstract

Laser powder bed fusion (L-PBF) is one of the most promising additive manufacturing (AM) methods which provides an exceptional opportunity to improve the existing designs and move toward fabricating fine features and complex geometries with higher efficiencies. Considering the layer-wise nature of this technique, the possibility of fabricating fine features is tied to the ability to deposit thin powder layers in this process. Since the powder layer thickness is directly dictated by the powder particle size, finer powders are required to further enhance the ability of the L-PBF technique in manufacturing fine features and intricate geometries. Accordingly, this study aims at investigating the processability of fine AlSi10Mg powder (D50 = 9 µm) by using the L-PBF process. The densification level, surface quality and dimensional accuracy of the final parts are investigated in a wide range of process parameters and are compared to those manufactured by the commonly used AlSi10Mg powder (referred to as coarse powder with D50 = 40 µm).The underlying reasons behind the different processability of fine and coarse powders are explored from the density, surface quality, microhardness and dimensional accuracy viewpoints through analyzing the flowability, bed packing density and optical absorption of powders. Moreover, the process-microstructuremicrohardness relationship is assessed in detail for both fine and coarse powders. This study reinforces the idea that the utilization of fine powders in the range used in this study for L-PBF processing is rather challenging.

The Influence of Particle Shape, Powder Flowability, and Powder Layer Density on Part Density in Laser Powder Bed Fusion

“…As the circularity and the Hausner ratio seemed to impact only the part density for WA powder, the influence of PLD on part density is evaluated in this section as the relevance of a high PLD for part quality is frequently stressed in literature [5,32,41,42]. Figure 12 shows the mean part porosity plotted against the PLD at scan speeds of 1000, 1500, and 2000 mm/s.…”

In-Situ Alloy Formation of a WMoTaNbV Refractory Metal High Entropy Alloy by Laser Powder Bed Fusion (PBF-LB/M)

“…Spherical powder particles are in general superior to irregular shaped particles with respect to flowability and are consequently preferable. Also very small particle fractions (<10 µm) should be avoided as they might impair recoatability and bear difficulties with respect to occupational safety [ 40 ]. Based on these criteria W-, Mo-, and Ta-powder was purchased from Tekna Plasma Europe SAS (Mâcon, France).…”

Surface Roughness Considerations in Design for Additive Manufacturing - A Literature Review

“…However, Artzt et al (2020) found the converse. Similarly, as particle powder size reduces, enabling the creation of finer features in parts, Balbaa et al (2021) found that the surface roughness increases, whereas Conlon and Azari (2018) found the opposite. Oter et al (2020) found through varying part positioning within an EOS machine, that the roughness is dependent on the part geometry and inclination of the walls due to the machine's laser incidence.…”