07 Fakultät Konstruktions-, Produktions- und Fahrzeugtechnik

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Publication Type: search.filters.UBSTyp.KonferenzbeitragInstitute: search.filters.UBSInstitut.Institut für StrahlwerkzeugeSubject: search.filters.subject.670

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    Local laser heat treatment of AlSi10Mg as-built parts produced by Laser Powder Bed Fusion
    (2024) Kramer, Steffen; Jarwitz, Michael; Schulze, Volker; Zanger, Frederik
    Today, complex structural components for lightweight applications are frequently manufactured by laser powder bed fusion (PBF-LB), often using aluminum alloys such as AlSi10Mg. However, the application of cyclic load cases can be challenging as PBF-LB produced AlSi10Mg parts typically have low ductility and corresponding brittle failure behavior in the as-built condition. Therefore, this paper presents investigations on the feasibility of a laser heat treatment of PBF-LB produced AlSi10Mg parts to locally increase the ductility and decrease the hardness in critical areas. Potential heat treatment process parameters were derived theoretically based on the temperature fields in the material calculated assuming three-dimensional heat conduction and a moving heat source. PBF-LB produced specimens were then laser heat treated at varying laser power and scan speed. Hardness measurements on metallographic cross sections showed hardness reductions of over 35 % without inducing hydrogen pore growth.
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    Comparison of in-process laser drying with furnace and vacuum drying to reduce moisture of AlSi10Mg powder processed in Laser Powder Bed Fusion
    (2024) Lubkowitz, Victor; Fayner, Leonie; Kramer, Steffen; Schulze, Volker; Zanger, Frederik
    In most powder bed-based laser melting systems (PBF-LB), metal powders must be handled without inertization but in an air atmosphere for a short time, increasing the AlSi10Mg powder moisture and reducing the achievable component density. Consequently, different drying methods were investigated. Drying in a furnace with an inert atmosphere, using a vacuum to evaporate the water at low temperatures, and vaporizing moisture layerwise from the spreaded powder with a defocused, low-power laser beam as a further process step of the PBF-LB process. Therefore, four different moisturized powders, which were dried with different settings for the drying methods, are analyzed. All drying methods reduce the moisture content of the powder, with in-process drying being the most effective. Due to the oxide layer growth around the particles during furnace and vacuum drying, the achievable sample density after drying is worse. In-process drying with low energy density is the best option to reach a reduction of hydrogen pores and an increase of density.