Browsing by Author "Wendler, Marco"

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    GRK 2802: Characterization of CrMnNi Steel Powders Obtained via Gas Atomization
    (Technische Universität Bergakademie Freiberg, 2026-06-22) Sherstneva, Anastasiia; Quitzke, Caroline; Bellé, Matheus Roberto; Wendler, Marco; Volkova, Olena
    To obtain a successful product during additive manufacturing, the powder as a raw material must have the high quality. The purpose of this work is to investigate CrMnNi steel powders obtained by inert gas atomization with nickel content: 3, 6, and 9 wt% and to identify dependencies between the powder size and morphology, solidification structure, and change in chemical composition and thermophysical properties. Particle size distribution is measured by a laser scattering analyzer: d50 value are 82.02, 69.32, and 75.54 μm for powders with 3, 6, and 9 wt%, respectively. Surface tension (ST) measurements are made by maximum bubble pressure method: for steels with 3, 6, and 9 wt% at temperature 1500 °C, ST is 1.01, 1.07, and 1.15 mNm 1, respectively. It is found that the change in particle size affects the chemical composition, the content of the ferromagnetic phase and secondary dendritic arm-spacing. Changes in the content of elements such as S, O, N, and Mn are determined, depending on the diameter of the particles. The influence of changes in content of S, O, and N on the thermophysical properties such as ST is investigated.
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    GRK2802: Correlation Between Particle Size, Secondary Dendrite Arm Spacing, and Local Cooling Rate in Gas-atomized Stainless Steel Powders for Additive Manufacturing
    (Technische Universität Bergakademie Freiberg, 2026-04-27) Bellé, Matheus Roberto; Sherstneva, Anastasiia; Hauser, Michael; Wendler, Marco; Volkova, Olena
    Additive manufacturing (AM) demands metallic powders with controlled microstructure and morphology to ensure high-performance components, especially in processes like Laser Powder Bed Fusion (PBF-LB). Gas atomization techniques such as Vacuum Inert Gas Atomization (VIGA) and Electrode Inert Gas Atomization (EIGA) are widely employed for producing stainless steel powders tailored for AM applications. In this study, the solidification behavior of such powders is investigated by analyzing the secondary dendrite arm spacing (SDAS) as a function of particle size (15–170 µm). SDAS is used as a microstructural indicator to estimate local cooling rates during atomization. Experimental results reveal that SDAS increases linearly for particles ≤ 100 µm and exponentially for larger particles, independent of steel composition, atomization gas, or method. Derived cooling rates, ranging from 104 to 107 K s-1, closely align with predictions from dimensionless criteria, affirming the relevance of such models under rapid solidification. Conversely, regressions developed for slower cooling conditions underestimate these values, emphasizing the need for high-fidelity models in atomization contexts. Notably, fine powders (< 25 µm) showed evidence of metastable δ-ferrite formation due to ultrafast cooling, as confirmed by magnetic saturation and XRD analyses. This work strengthens the predictive control of powder solidification behavior, aiding in the design of high-performance AM components.