Effects of Powder Size Distribution on the Manufacturability and Microstructure of Fe-Co-V Alloy Fabricated via LPBF

The influence of particle size on the processability and properties of iron-cobalt soft magnetic materials remains an area of limited exploration. In this study, two types of iron-cobalt powders with differing production methods and particle sizes, designated as ultra-fine and commercial powders, were selected to investigate these effects. For the ultra-fine powder, layer thicknesses of 0.01 mm and 0.03 mm were used to assess processability, while a 0.05 mm layer thickness was employed for the commercial powder. Samples with high relative densities and similar processing parameters were chosen for detailed analysis. The measured relative densities were 91.45%, 93.34%, and 96.25% for the 0.01 mm, 0.03 mm, and 0.05 mm samples, respectively. Distinct differences in microstructure and properties were observed. All samples exhibited nanoscale particle features, with the commercial sample showing the highest particle count and the finest diameters. The 0.01 mm sample was comparable in particle count, while the 0.03 mm sample showed similar particle diameters. In the ultra-fine powder samples, the melt track contours were not well-defined, whereas in the commercial powder sample, etched with Nital revealed clear melting tracks. Additionally, the nanoscale particles disappeared post-etching, and dendritic structure was observed in the transition areas of the melting tracks, highlighting the differences in material behavior based on powder properties and processing conditions.