Investigation of 3D Plasma Metal Deposition (3DPMD) with Aluminium powder
D. Vieweger1*, Y. Tong1, P. Mayr1
1 Technical University of Munich, Chair of Materials Engineering of Additive Manufacturing
*daniel.vieweger@tum.de
As additive manufacturing (AM) continues to revolutionize industrial production, 3D Plasma Metal Deposition (3DPMD), a novel directed energy deposition (DED) variant based on the plasma-transferred arc welding process, is emerging as a promising technology, offering distinctive capabilities for fabricating high-quality metal components with unique properties. [1,2] Despite its potential, there has been very limited exploration of its application, especially with aluminium powder.
This work aims to fill this research gap by investigating the feasibility and challenges of utilizing 3DPMD with aluminium powder, addressing both process and material related complexities. Moreover, it should highlight the inherent difficulties encountered when working with aluminium alloys in DED, drawing insights from more extensively studied DED processes like Wire Arc Additive Manufacturing and Laser-based DED. [3–6]
Key objectives include conducting fundamental research to understand the process-structure-properties relationships specific to 3DPMD with aluminium. Several test series with single deposits and multilayer build-ups have been performed to investigate different aspects of the process. The key parameters identified were the main current, plasma gas flow, powder feed rate, travel speed and standoff distance. Additionally, the thermal behavior of the substrate plate has been varied. The investigations focused on dimensional characteristics, microstructure, process defects, and mechanical properties, particularly hardness. The substrate plate material was a 5082 alloy, and the powder was AlSi10Mg.
The test series of the single deposits showed the influence of the selected process parameters on the geometric properties such as deposition height, width, and penetration depth. For improved deposition efficiency, the tracks were aimed to have a maximized height-to-width ratio. The right penetration depth is important to ensure proper structural bonding of the layers. Both were achieved by reducing the plasma gas flow, decreasing the travel speed, and increasing the powder feed rate. The samples of the multilayer build-ups revealed the characteristic microstructure and process defects observed in DED of aluminium. In particular, long columnar dendritic grains oriented along the build-up direction and elevated porosity due to gas inclusions were observed. The average density of the cross-sections ranged from 96% to 97%. The respective heat-affected zones of each layer showed a significantly finer microstructure compared to the rest of the sample. The predominant phases of AlSi10Mg processed with 3DPMD were identified. The observed hardness data did not indicate correlations with the microstructure.
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