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To manufacture functional components using laser powder bed fusion (PBF-LB/M), the execution of a parameter development with the specific material and machine is an indispensable step. Typically, in the search for the optimal parameter set, the volumetric energy density (VED) used to melt the material serves as an adjustment variable, while the resulting part density as the target parameter. Although this approach effectively reduces the process parameters search-space, additional criteria concerning part quality should be considered in the development. This paper introduces a systematic parameter selection approach, refining the characterization process for processing the nickel-based superalloy Haynes® 282®. The presented strategy not only incorporates the density as target condition but also considers the surface quality and dimensional accuracy of the manufactured samples, crucial for near-net-shape manufacturing. Additionally, three porosity measurement methods (Archimedes method, microscopy, gaspycnometry) for AM metal parts are compared, and their validity for this purpose is discussed.
This study examines the impact of varying oxidation levels in nickel-based Haynes 282 powder on particle degradation during laser powder bed fusion (PBF-LB|M). Four powder batches with oxygen content levels of approximately from 140 ppm to1400 ppm were processed using PBF-LB|M. A powder collection container was fabricated to sample unmelted powder from heat-affected regions of the powder bed. Recoating and melting proceeded without issues; however, increased fume emissions were observed at higher oxidation levels, indicating intensified spatter formation. Post-process analysis revealed that finer particles exhibited greater surface oxidation due to their higher surface-to-volume ratio. Despite significant oxygen uptake, chemical analysis showed no measurable changes in key alloying elements in either the unmelted or spatter particles. Additionally, changes in particle size distribution became more pronounced at high oxidation levels. These findings provide a basis for understanding oxidation-driven degradation and optimizing powder reuse strategies to maintain material performance.
Die vorliegende Studie untersucht den Einfluss unterschiedlicher Oxidationsgrade des im PBF-LB/M-Prozess verwendeten Ausgangspulvers auf dessen Degradation am Beispiel der Nickelbasis-Superlegierung Haynes 282. Zu diesem Zweck wurden vier Pulverbatches mit Sauerstoffgehalten zwischen etwa 140 ppm und 1400 ppm mittels PBF-LB/M verarbeitet. Zur gezielten Entnahme aufgeschmolzener Pulverpartikel aus wärmebeeinflussten Bereichen des Pulverbetts wurde ein spezieller Auffangbehälter konstruiert und mitgedruckt. Der Beschichtungs- und Schmelzprozess verlief störungsfrei. Bei höheren Oxidationsgraden wurde jedoch eine verstärkte Rauchentwicklung beobachtet, was erste Hinweise auf eine intensivere Spritzerbildung lieferte. Die Untersuchungen nach dem Bauprozess ergaben, dass insbesondere die feinen Partikelfraktionen infolge ihres hohen Oberflächen-zu-Volumen-Verhältnisses eine verstärkte Oxidation aufwiesen. Neben einer signifikanten Sauerstoffanreicherung konnten keine weiteren signifikanten Veränderungen der Hauptlegierungselemente in unaufgeschmolzenen Pulverpartikeln sowie in Spritzerpartikeln festgestellt werden. Darüber hinaus wurde bei stark oxidierten Pulvern eine signifikante Veränderung der Partikelgrößenverteilung beobachtet. Die gewonnenen Erkenntnisse leisten einen wichtigen Beitrag zum Verständnis oxidationsbedingter Degradationsmechanismen und bilden die Grundlage für die Optimierung von Strategien zur Wiederverwendung von Pulver im PBF-LB/M-Prozess, wodurch die Materialperformance gesichert werden kann.
This study examines the impact of varying oxidation levels in nickel-based Haynes 282 powder on particle degradation during laser powder bed fusion (PBF-LB/M). Four powder batches with oxygen content levels of approximately from 140 ppm to1400 ppm were processed using PBF-LB/M. A powder collection container was fabricated to sample unmelted powder from heat-affected regions of the powder bed. Recoating and melting proceeded without issues; however, increased fume emissions were observed at higher oxidation levels, indicating intensified spatter formation. Post-process analysis revealed that finer particles exhibited greater surface oxidation due to their higher surface-to-volume ratio. Despite significant oxygen uptake, chemical analysis showed no measurable changes in key alloying elements in either the unmelted or spatter particles. Additionally, changes in particle size distribution became more pronounced at high oxidation levels. These findings provide a basis for understanding oxidation-driven degradation and optimizing powder reuse strategies to maintain material performance.
To manufacture functional components using laser powder bed fusion (PBF-LB/M), the execution of a parameter development with the specific material and machine is an indispensable step. Typically, in the search for the optimal parameter set, the volumetric energy density (VED) used to melt the material serves as an adjustment variable, while the resulting part density as the target parameter. Although this approach effectively reduces the process parameters search-space, additional criteria concerning part quality should be considered in the development. This paper introduces a systematic parameter selection approach, refining the characterization process for processing the nickel-based superalloy Haynes® 282®. The presented strategy not only incorporates the density as target condition but also considers the surface quality and dimensional accuracy of the manufactured samples, crucial for near-net-shape manufacturing. Additionally, three porosity measurement methods (Archimedes method, microscopy, gaspycnometry) for AM metal parts are compared, and their validity for this purpose is discussed.
Reuse of powder in powder bed additive manufacturing is a common practice to enhance sustainability and reduce costs. However, the reusability of metal powder is limited by the oxidation of the powders. Even in a protective atmosphere, each build job leads to gradual oxidation of the powder, which has led to concerns about its impact on powder and part properties. Consequently, strict confidence intervals for oxygen content in nickel-based alloy feedstocks are enforced in the industry. Despite this, there is currently a lack of in-depth studies investigating the specific influence of oxygen on Haynes 282, a widely used nickel-based alloy. This study examines artificially aged Haynes 282 powder batches with oxygen content of 160 ppm, 330 ppm, 1050 ppm, and 1420 ppm. Detailed powder characterization was performed, including morphology, chemical composition, particle size, flowability, and packing behavior. Components were fabricated via PBF-LB/M to evaluate density and mechanical properties. The results showed that higher oxidation levels improved powder flowability and packing density. However, in manufactured parts, irregular melt tracks and increased surface roughness were observed, which could easily be removed by post-processing. No significant differences in density or mechanical properties at room temperature, such as tensile strength and elongation, were found. These findings indicate that H282 powder potentially remains suitable for reuse, even when the batches exhibit increased oxygen content, supporting discussions on revising the existing oxygen content confidence intervals for nickel-based alloys. The results highlight the potential for optimizing recycling strategies and reducing material waste in additive manufacturing processes.
Influence of initial powder oxidation on mechanical properties of components fabricated via PBF-LB/M
(2026)
The reuse of feedstock in laser powder bed fusion of metals (PBF-LB/M) enhances sustainability and reduces production costs but is limited by progressive degradation of the material [1]. One contributor to powder degradation is oxidation, even in protective atmospheres [2]. This study investigates how the initial oxidation state of Haynes 282, a nickel-based alloy for high-temperature applications, influences its performance at both ambient and elevated temperatures (850 °C). For this purpose, four feedstock batches with oxygen contents ranging from approximately 140 ppm to 1400 ppm were produced by controlled oxidation of virgin powder in a laboratory furnace.
Microscopy analysis revealed that higher oxidation levels promoted irregular melt pool morphology and increased surface roughness, accompanied by a reduction in grain size. Electron probe microanalysis revealed that the oxide layers observed on the surface of the manufactured specimens in the as-build condition consisted primarily of aluminium and titanium oxides. Oxygen analysis via inert gas fusion on heat-treated specimens measured approximately 90 ppm in material from virgin feedstock and approximately 600 ppm in material from the most oxidized batch. Notwithstanding these discrepancies, the part porosity and the room-temperature tensile properties, including ultimate strength and elongation at break, remained largely unaltered. Conversely, creep testing at elevated temperatures under application-relevant conditions showed a pronounced decline in creep resistance and a corresponding increase in creep strain with rising oxygen content. However, both the tensile strength and the deformation mechanisms observed in high-temperature tensile tests remained comparable across all batches. These findings indicate that while the use of oxidized powder is viable for less demanding service conditions, strict powder quality control is imperative when manufacturing components for high-temperature applications.
