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-microstructure-microhardness 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.

激光粉末床熔合（L-PBF）是最有前途的增材制造（AM）方法之一，它提供了一个难得的机会来改进现有设计，并朝着制造具有更高效率的精细特征和复杂几何形状迈进。考虑到该技术的逐层特性，制造精细特征的可能性与在此过程中沉积薄粉末层的能力有关。由于粉末层的厚度直接取决于粉末的粒径，因此需要更细的粉末来进一步增强L-PBF技术制造精细特征和复杂几何形状的能力。因此，本研究旨在通过使用L-PBF工艺研究AlSi10Mg细粉（D50 = 9 µm）的可加工性。致密化程度 在广泛的工艺参数中研究了最终零件的表面质量和尺寸精度，并与常用的AlSi10Mg粉末（称为D50 = 40 µm的粗粉）制造的产品进行了比较。通过分析粉末的流动性，床堆积密度和吸光度，从密度，表面质量，显微硬度和尺寸精度的角度探讨了细粉和粗粉不同加工性能的根本原因。而且，对于细粉和粗粉都详细评估了过程-微观结构-显微硬度关系。这项研究强化了这样的想法，即在本研究中使用的L-PBF加工范围内的细粉的利用颇具挑战性。