Powder Properties and Flowability Measurements of Tailored Nanocomposites for Powder Bed Fusion Applications

The modification of metal alloy powders by coating with nanoparticles offers the possibility to improve additive manufacturing processes, in particular the powder bed fusion of metals with laser beams (PBF/LB-M), from the material side of view. Subsequently, component qualities including mechanical properties and microstructural characteristics could be improved.

Highlights

Successful homogenous coatings were obtained for SiC and FLG on three metal powders.

SiC, FLG, and IOB coatings exhibit higher laser light absorption as feedstock materials.

The flowability of three metal powders could be enhanced by adding SiC nanoparticles.

The flowability measurement results by ring shear tests, rotating drum and powder rheometer (Anton Paar) show the same general tendencies.

Ring shear measurements were found to be more sensitive than rotating drum measurements.

Furthermore, the modification enables improved energy utilization due to an increase in laser absorption. In this work three commercial additive manufacturing powders, namely stainless steel (1.4404), tool steel (1.2709), and aluminum alloy (3.2381) were coated with three different nanoparticles (Silicon carbide (SiC), few layer graphene (FLG), and iron oxide black (IOB) to increase the laser light absorption in the PBF/LB/M process, mechanical properties, and flowability of the powders. The coating was conducted within a fluidized bed system, resulting in homogeneous coatings.

This study demonstrates, that well scalable processes i.e. stirred media milling and fluidized bed coating have the potential to improve the commercial AM powders regarding their bulk density, flowability, and energy absorption, which is a crucial step towards an improvement in the efficiency of the whole PBF process. Overall important information and relations were gathered to transfer them to the real powder deposition process in future work.

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Article information: A. Lüddecke, O. Pannitz, H. Zetzener, J.T. Sehrt, A. Kwade. Powder Properties and Flowability Measurements of Tailored Nanocomposites for Powder Bed Fusion Applications, Materials & Design, 2021. https://doi.org/10.1016/j.matdes.2021.109536.