Controlling the mechanical properties of laser powder bed fusion manufactured AlSi10Mg using optimized oscillating scan paths

Abstract

In the field of metal additive manufacturing, laser powder bed fusion (L-PBF) stands out for its maturity. The path the laser takes over the powder, in this study AlSi10Mg, is determined by a large set of separate parameters; the combination of which offers ample room for optimization. The close ties between the parameters chosen, and the resulting mechanical properties, are what motivates the extensive research done in this field. This study changed the scan line path into a circular oscillation (prolate trochoid) and narrows down a large set of parameters to two sets that exhibit significant differences from traditional scan lines in terms of density, porosity distribution, tensile strength, elongation at fracture, hardness, surface roughness, and melt pool (MP) shape. Remarkable upper bounds for MP size were also characterized for the first time in this work. Some of the noteworthy findings consist of an up to 70% reduction in surface roughness, up to a 40% increase in the elongation at fracture, and up to a 150μm range of hatching distances to produce a part with under 0.5% porosity. The last of which leads to an overall increase in the robustness of the L-PBF manufacturing process by reducing the sensitivity to parameter fluctuations.