TY - CONF A1 - Fabry, Çağtay T1 - Towards arc welding reference data: Open Science laboratories at BAM N2 - As industries move for ever faster development and adoption cycles of emerging new technologies in the field of welding, the meticulous and longer-winded approach of the scientific research process can feel harder to integrate. To help bridge this gap and increase the speed, quality, and adoption rate of publicly funded research, the Bundesanstalt für Materialforschung und -prüfung (BAM) continues to work towards enabling scientists with direct access to necessary software tools and - in the future – highest quality welding research reference data to further foster collaborations. On the experimental side, the arc welding group at BAM division 9.3 “welding technologies” is continuing to expand and upgrade its capacities of robotic welding systems with integrated state of the art sensor technologies and software solutions. This allows all experiments to be recorded and measured in micro-millimeter accuracy and at sub-millisecond precision, including welding process data, complete spatial geometry and temperature measurements, process video recordings and more. The custom software-based solutions and interfaces allow scaling of the welding systems from large thick plate offshore applications to small additive repair weldments in wind turbine blades to multi-hour continuous weldments in additive manufacturing applications. In addition to the data gathered during the welding process itself, the relevant testing results and materials properties produced at BAM or externally can be integrated seamlessly. This allows detailed traceability of all results back to the actual welding process. Regardless of the scope and application, complete datasets can be made accessible for research or industry partners in the highest resolution based on the open source WelDX (welding data exchange) file format. Figure 1. Welding experiment representation including dynamic process data, cross-section imaging and hardness measurements from a single weldx file. The talk will give an overview of the experimental facilities and workflows as well as current software developments with a focus on research data quality assurance, traceability, and accessibility. Based on the integration into latest research trends and activities of the “welding technologies” division, the path to publishing reference datasets for arc welding process for various applications and materials is outlined and discussed. T2 - 4th Symposium on Materials and Additive Manufacturing - Additive 2024 CY - Berlin, Germany DA - 12.06.2024 KW - Additive Manufacturing KW - Arc welding KW - DED-arc KW - Research data KW - Reference data PY - 2024 AN - OPUS4-60249 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Altenburg, Simon T1 - Thermography in laser powder bed fusion of metals: time over threshold as feasible feature in thermographic data N2 - Thermography is one on the most promising techniques for in-situ monitoring for metal additive manufacturing processes. The high process dynamics and the strong focus of the laser beam cause a very complex thermal history within the produced specimens, such as multiple heating cycles within single layer expositions. This complicates data interpretation, e.g., in terms of cooling rates. A quantity that is easily calculated is the time a specific area of the specimen is at a temperature above a chosen threshold value (TOT). Here, we discuss variations occurring in time-over-threshold-maps during manufacturing of a defect free cuboid specimen. T2 - 15th Quantitative InfraRed Thermography conference CY - Online meeting DA - 21.09.2020 KW - Additive Manufacturing KW - Process monitoring KW - Thermography KW - L-PBF KW - Time over threshold PY - 2020 AN - OPUS4-51630 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sprengel, Maximilian T1 - The relaxation of macroscopic residual stresses in laser powder bed fused stainless steel 316L N2 - The processing of stainless steel 316L using the additive manufacturing process Laser Powder Bed Fusion (LPBF) can widen its field of application due to a strong increase in Yield strength, without making major compromises on the ductility nor its outstanding corrosion and oxidation properties. Furthermore, improved designs that either reduce the weight or optimise the function of a part can be obtained using LPBF. These benefits are however counterbalanced by the proneness of LPBF to inducing high Residual Stresses (RS) during manufacturing. The characterisation and monitoring of these RS are of paramount importance for the wider acceptance of the LPBF process. This study focuses on the relaxation of the initial macroscopic RS present in an LPBF 316L as-built prism that undergoes various routes of manufacturing steps to achieve different specimen geometries and stress relieving treatments. The RS are determined using Angle-Dispersive (AD) and Time-of-Flight (TOF) neutron diffraction. The results reveal high tensile RS close to the surfaces and compressive RS near the centre of the as-built parts. The reduction in size and change of geometry heavily impact the stress ranges of the remaining RS, with lower stress ranges in cylindrical shaped compared to rectangular shaped specimens. Also, the application of different stress relieving heat treatments showed that heat-treating temperatures above 800 °C are necessary to obtain a strong relaxation in LPBF 316L. T2 - The second European Conference on the Structural Integrity of Additively Manufactured Materials CY - Online meeting DA - 08.09.2021 KW - Residual Stress KW - Additive Manufacturing KW - Neutron Diffraction PY - 2021 AN - OPUS4-53263 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ulbricht, Alexander T1 - The Influence of the Temperature Gradient on the Distribution of Residual Stresses in AM AISI 316L N2 - Steep temperature gradients and solidification shrinkage are the main contributors to the formation of residual stresses in additively manufactured metallic parts produced by laser beam melting. The aim of this work was to determine the influence of the temperature gradient. Diffraction results show a similar pattern for both specimens, indicating the shrinkage to be more dominant for the distribution of residual stresses than the temperature gradient. Thermography results imply that a higher energy input result in higher compressive residual stresses in the bulk. T2 - Workshop on Additive Manufacturing: Process, materials, simulation & implants CY - BAM, Berlin, Germany DA - 13.05.2019 KW - Computed tomography KW - Online Process Monitoring KW - Additive Manufacturing KW - Powder Bed Fusion KW - Selected Laser Melting KW - Neutron Diffraction PY - 2019 AN - OPUS4-48075 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Witte, Julien T1 - The Impact of Ultrasonic-Assisted Milling and Alloying Elements on the Surface Integrity of Additively Manufactured Iron Aluminides N2 - The increasing focus on energy and resource efficiency has driven the implementation of additive manufacturing (AM) of high-performance materials, particularly in lightweight constructions with optimization of material efficiency. Iron aluminides (FeAl) hold great potential due to their low density, excellent corrosion and wear resistance, high-temperature stability, and vast availability. However, the inherent heterogeneity and anisotropy of FeAl-AM structures pose significant challenges, especially regarding hardness and brittleness. These material characteristics complicate the mostly necessary post-processing via mechanical finish machining, often resulting in elevated cutting forces, accelerated tool wear, and suboptimal surface integrity. Ultrasonic-assisted milling (USAM), a hybrid machining process, offers significant advantages over conventional milling (CM), including the reduction of cutting forces and tool wear. Notably, USAM has been demonstrated to decrease surface defect density and mitigate tensile residual stresses, while potentially inducing beneficial compressive residual stresses within the depth profile of the component’s surface. These effects can significantly enhance crack propagation resistance, improve corrosion behavior, and extend the fatigue life of components in safety-relevant applications. The present study investigates the effects of additional alloying elements such as molybdenum, nickel, titanium and Vanadium in FeAl as well as milling parameters, including cutting speed vc and feed rate fz, on the surface integrity with special regard to residual stress formations. T2 - 4th International Conference on Advanced Joining Processes CY - Coimbra, Portugal DA - 16.10.2025 KW - Additive Manufacturing KW - Wear Protection KW - Ultrasonic-assisted Milling KW - Iron-aluminides KW - MPEA KW - Surface Integrity KW - Residual Stresses PY - 2025 AN - OPUS4-65235 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Witte, Julien T1 - The Impact of Ultrasonic-Assisted Milling and Alloying Elements on the Surface Integrity of Additively Manufactured Iron Aluminides N2 - The increasing focus on energy and resource efficiency has driven the implementation of additive manufacturing (AM) of high-performance materials, particularly in lightweight constructions with optimization of material efficiency. Iron aluminides (FeAl) hold great potential due to their low density, excellent corrosion and wear resistance, high-temperature stability, and vast availability. However, the inherent heterogeneity and anisotropy of FeAl-AM structures pose significant challenges, especially regarding hardness and brittleness. These material characteristics complicate the mostly necessary post-processing via mechanical finish machining, often resulting in elevated cutting forces, accelerated tool wear, and suboptimal surface integrity. Ultrasonic-assisted milling (USAM), a hybrid machining process, offers significant advantages over conventional milling (CM), including the reduction of cutting forces and tool wear. Notably, USAM has been demonstrated to decrease surface defect density and mitigate tensile residual stresses, while potentially inducing beneficial compressive residual stresses within the depth profile of the component’s surface. These effects can significantly enhance crack propagation resistance, improve corrosion behavior, and extend the fatigue life of components in safety-relevant applications. The present study investigates the effects of additional alloying elements such as molybdenum, nickel, titanium and Vanadium in FeAl as well as milling parameters, including cutting speed vc and feed rate fz, on the surface integrity with special regard to residual stress formations. T2 - BMDK der OvGU Magdeburg CY - Magdeburg, Germany DA - 10.12.2025 KW - Additive Manufacturing KW - Wear Protection KW - Ultrasonic-assisted Milling KW - Iron-aluminides KW - MPEA KW - Surface Integrity KW - Residual Stresses PY - 2025 AN - OPUS4-65234 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schröder, Jakob T1 - The heat treatment of L-PBF Inconel 718: A manyfold problem N2 - The interest to additively manufacture Nickel-based superalloys has substantially grown within the past decade both academically and industrially. More specifically, additive manufacturing processes such as laser powder bed fusion (LPBF) offer the ability to produce dense parts within a single manufacturing step. In fact, the exceptional freedom in design associated with the layer-based nature of the processes is of particular interest for the complex shapes typically required in turbine applications. In certain cases, the overall part performance can be achieved by tailoring the microstructure and the crystallographic texture to the specific application. However, these advantages must be paid at a price: the large local temperature gradients associated with the rapid melting and solidification produce parts that inherently contain large residual stress in the as-manufactured state. In addition, the presence of pores in the final part may further affect the in-service part failure. As among Nickel-based alloys Inconel 718 exhibits excellent weldability, this alloy has been widely studied in open research in the domain of LPBF. However, significant microsegregation of the heavier alloying elements such as Niobium and Molybdenum accompanied by dislocation entanglements may preclude the application of conventional heat treatment schedules. Therefore, different post processing heat treatments are required for laser powder bed fused Inconel 718 as compared to conventional variants of the same alloy. In this study, we investigated two different heat treatment routes for LPBF Inconel 718. In a first routine, the samples were stress relieved and subsequently subjected to hot isostatic pressing (HIP) followed by a solution heat treatment and a two-step age (referred to as FHT). In a second routine, the samples were subjected to a single-step direct age post stress relieving heat treatment (referred to DA). We investigated the consequences of such heat treatment schedules on the microstructure, texture, and mechanical behavior. We show that by applying a DA heat treatment the typical columnar microstructure possessing a crystallographic texture is retained, while an equiaxed untextured microstructure prevails in case of an FHT heat treatment. We further evaluate how these heat treatments affect the mechanical behaviour on the macroscopic and microscopic scale. T2 - 4th European Symposium on Superalloys and their Applications EuroSuperalloys 2022 CY - Bamberg, Germany DA - 18.09.2022 KW - Electron Backscatter Diffraction KW - Additive Manufacturing KW - Laser Powder Bed Fusion KW - Mechanical Behavior KW - Heat Treatment KW - X-Ray Diffraction PY - 2022 AN - OPUS4-55811 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Günster, Jens A1 - Sänger, Johanna A1 - Pauw, Brian Richard T1 - Tailoring powder properties for the light based volumetric additive manufacture of Ceramics N2 - Manipulating ceramic powder compacts and ceramic suspensions (slurries) within their volume with light requires a minimum transparency of the materials. Compared to polymers and metals, ceramic materials are unique as they offer a wide electronic band gap and thus a wide optical window of transparency. The optical window typically ranges from below 0.3 µm up to 5µm wavelength. Hence, to penetrate with light into the volume of a ceramic powder compound, its light scattering properties need to be investigated and tailored. In the present study we introduce the physical background and material development strategies to apply two-photon-polymerization (2PP), and other volumetric methods for the additive manufacture of filigree structures within the volume of ceramic slurries. T2 - ICACC 2024 CY - Daytona Beach, Florida, USA DA - 28.01.2024 KW - Additive Manufacturing KW - Two Photon Polymerization KW - Advanced ceramics PY - 2024 AN - OPUS4-59889 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Günster, Jens T1 - Tailoring powder properties for the light based volumetric additive manufacture of Ceramics N2 - In order to be able to manipulate ceramic powder compacts and ceramic suspensions (slurries) within their volume with light, a minimum transparency of the materials is required. Compared to polymers and metals, ceramic materials are characterized by the fact that they have a wide electronic band gap and therefore a wide optical window of transparency. The optical window generally ranges from less than 0.3 µm to 5 µm wavelength. In order to focus light into the volume of a ceramic powder compact, its light scattering properties must therefore be tailored. In this study, we present the physical background and material development strategies for the application of two-photon polymerization (2PP) and selective volumetric sintering for the additive manufacturing of structures in the volume of ceramic slips and green compacts. T2 - SmartMade 2024 CY - Osaka, Japan DA - 10.04.2024 KW - Additive Manufacturing KW - Two Photon Polymerization KW - Advanced ceramics PY - 2024 AN - OPUS4-59888 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sprengel, Maximilian T1 - Surface and bulk residual stress in laser powder bed fused 316L: Influence of inter layer time and scanning velocity N2 - The influence of the inter-layer-time and the scanning velocity on the surface and bulk residual stress in laser powder bed fused 316L specimens was investigated. This study combines X-ray and neutron diffraction results with the thermal history of the specimens acquired through in-situ process monitoring. The process parameter variations were observed to directly influence the thermal history, which gave new insights in the assessment of the residual stress results. T2 - The 11th International Conference on Residual Stress CY - Nancy, Frankreich DA - 28.03.2022 KW - AGIL KW - Residual Stress KW - X-ray and Neutron Diffraction KW - Additive Manufacturing KW - Stainless Steel PY - 2022 AN - OPUS4-54582 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -