TY - CONF A1 - Przyklenk, A. A1 - Evans, Alexander A1 - Bosse, H. A1 - Balsamo, A. A1 - O'Connor, D. A1 - Favre, G. A1 - Phillips, D. T1 - Progress of the European Metrology Network for Advanced Manufacturing N2 - The European Metrology Network (EMN) for Advanced Manufacturing has been established in June 2021. Currently nine EMNs focussing on different important topics of strategic importance for Europe exist and form an integral part of EURAMET, the European Association of National Metrology Institutes (NMI). EMNs are tasked to ▪ develop a high-level coordination of the metrology community in Europe in a close dialogue with the respective stakeholders (SH) ▪ develop a strategic research agenda (SRA) within their thematic areas ▪ provide contributions to the European Partnership on Metrology research programme Based on the analysis of existing metrology infrastructures and capabilities of NMIs, the metrology research needs for advanced manufacturing are identified in close cooperation with academic, governmental and industrial stakeholders. Here, we report on the progress of the EMN for Advanced Manufacturing. T2 - Euspen 22nd International Conference & Exhibition (Euspen 2022) CY - Genf, Switzerland DA - 30.05.2022 KW - JNP AdvManuNet KW - Metrology KW - Advanced manufacturing KW - European Metrology Network KW - EMN PY - 2022 AN - OPUS4-55805 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schröder, Jakob A1 - Mishurova, Tatiana A1 - Fritsch, Tobias A1 - Serrano Munoz, Itziar A1 - Evans, Alexander A1 - Sprengel, Maximilian A1 - Klaus, M. A1 - Genzel, C. A1 - Schneider, J. A1 - Bruno, Giovanni 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 - JOUR A1 - Roveda, Ilaria A1 - Serrano Munoz, Itziar A1 - Mishurova, Tatiana A1 - Madia, Mauro A1 - Pirling, T. A1 - Evans, Alexander A1 - Klaus, M. A1 - Haubrich, J. A1 - Requena, G. A1 - Bruno, Giovanni T1 - Influence of a 265 °C heat treatment on the residual stress state of a PBF-LB/M AlSi10Mg alloy N2 - Laser Powder Bed Fusion (PBF-LB/M) additive manufacturing (AM) induces high magnitude residual stress (RS) in structures due to the extremely heterogeneous cooling and heating rates. As the RS can be deleterious to the fatigue resistance of engineering components, great efforts are focused on understanding their generation and evolution after post-process heat treatments. In this study, one of the few of its kind, the RS relaxation induced in an as-built PBF-LB/M AlSi10Mg material by a low-temperature heat treatment (265 °C for 1 h) is studied by means of X-ray and neutron diffraction. Since the specimens are manufactured using a baseplate heated up to 200 °C, low RS are found in the as-built condition. After heat treatment a redistribution of the RS is observed, while their magnitude remains constant. It is proposed that the redistribution is induced by a repartition of stresses between the a-aluminium matrix and the silicon phase, as the morphology of the silicon phase is affected by the heat treatment. A considerable scatter is observed in the neutron diffraction RS profiles, which is principally correlated to the presence (or absence) of pockets of porosity developed at the borders of the chessboard pattern. KW - Neutron diffraction KW - Additive manufacturing PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-565115 DO - https://doi.org/10.1007/s10853-022-07997-w SN - 1573-4803 VL - 57 SP - 22082 EP - 22098 PB - Springer Science + Business Media CY - Dordrecht AN - OPUS4-56511 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Evans, Alexander A1 - Bruno, Giovanni A1 - Mishurova, Tatiana A1 - Serrano Munoz, Itziar A1 - Roveda, Ilaria A1 - Fritsch, Tobias A1 - Ulbricht, Alexander A1 - Sprengel, Maximilian A1 - Schröder, Jakob T1 - Residual stresses and micromechanical properties of additively manufactured metals: why do we need a paradigm shift? N2 - An overview of the challenges and successes in the methodology to characherise residual stresses and micromechnical properties in additively manufactured metals T2 - CAM2 Annual Seminar 2022 - 5-year journey CY - Gothenburg, Sweden DA - 24.10.2022 KW - Additive Manufacturing KW - Residual stress KW - AGIL KW - MANUFACT KW - Micromechnical properties PY - 2022 AN - OPUS4-56466 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schröder, Jakob A1 - Evans, Alexander A1 - Polatidis, E. A1 - Capek, J. A1 - Mohr, Gunther A1 - Serrano Munoz, Itziar A1 - Bruno, Giovanni T1 - Texture Dependent Micromechanical Anisotropy of Laser Powder Bed Fused Inconel 718 N2 - Additive manufacturing methods such as laser powder bed fusion (LPBF) allow geometrically complex parts to be manufactured within a single step. However, as an aftereffect of the localized heat input, the rapid cooling rates are the origin of the large residual stress (RS) retained in as-manufactured parts. With a view on the microstructure, the rapid directional cooling leads to a cellular solidification mode which is accompanied by columnar grown grains possessing crystallographic texture. The solidification conditions can be controlled by the processing parameters and the scanning strategy. Thus, the process allows one to tailor the microstructure and the texture to the specific needs. Yet, such microstructures are not only the origin of the mechanical anisotropy but also pose metrological challenges for the diffraction-based RS determination. In that context the micromechanical elastic anisotropy plays an important role: it translates the measured microscopic strain to macroscopic stress. Therefore, it is of uttermost importance to understand the influence of the hierarchical microstructures and the texture on the elastic anisotropy of LPBF manufactured materials. This study reveals the influence of the build orientation and the texture on the micro-mechanical anisotropy of as-built Inconel 718. Through variations of the build orientation and the scanning strategy, we manufactured specimens possessing [001]/[011]-, [001]-, and [011]/[111]-type textures. The resulting microstructures lead to differences in the macroscopic mechanical properties. Even further, tensile in-situ loading experiments during neutron diffraction measurements along the different texture components revealed differences in the microstrain response of multiple crystal lattice planes. In particular, the load partitioning and the residual strain accumulation among the [011]/[111] textured specimen displayed distinct differences measured up to a macroscopic strain of 10 %. However, the behavior of the specimens possessing [001]/[011]-and [001]-type texture was only minorly affected. The consequences on the metrology of RS analysis by diffraction-based methods are discussed. T2 - International Conference on Additive Manufacturing ICAM 2022 CY - Orlando, FL, USA DA - 31.10.2022 KW - Laser powder bed fusion KW - Neutron diffraction KW - Electron backscatter diffraction KW - Mechanical behavior PY - 2022 AN - OPUS4-56376 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Oster, Simon A1 - Becker, Tina A1 - Breese, Philipp Peter A1 - Scheuschner, Nils A1 - Altenburg, Simon T1 - Machine Learning based defect detection in Laser Powder Bed Fusion utilizing thermographic feature data N2 - The formation of irregularities such as keyhole porosity pose a major challenge to the manufacturing of metal parts by laser powder bed fusion (PBF-LB/M). In-situ thermography as a process monitoring technique shows promising potential in this manner since it is able to extract the thermal history of the part which is closely related to the formation of irregularities. In this study, we investigate the utilization of machine learning algorithms to detect keyhole porosity on the base of thermographic features. Here, as a referential technique, x-ray micro computed tomography is utilized to determine the part's porosity. An enhanced preprocessing workflow inspired by the physics of the keyhole irregularity formation is presented in combination with a customized model architecture. Furthermore, experiments were performed to clarify the role of important parameters of the preprocessing workflow for the task of defect detection . Based on the results, future demands on irregularity prediction in PBF-LB/M are derived. T2 - International Conference on NDE 4.0 CY - Berlin, Germany DA - 24.10.2022 KW - Laser Powder Bed Fusion KW - Thermography KW - In-situ Monitoring KW - Convolutional Neural Networks PY - 2022 AN - OPUS4-56332 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ávila Calderón, Luis Alexander A1 - Rehmer, Birgit A1 - Schriever, Sina A1 - Ulbricht, Alexander A1 - Agudo Jácome, Leonardo A1 - Sommer, Konstantin A1 - Mohr, Gunther A1 - Skrotzki, Birgit A1 - Evans, Alexander T1 - Creep and creep damage behavior of stainless steel 316L manufactured by laser powder bed fusion N2 - This study presents a thorough characterization of the creep properties of austenitic stainless steel 316L produced by laser powder bed fusion (LPBF 316L) contributing to the sparse available data to date. Experimental results (mechanical tests, microscopy, X-ray computed tomography) concerning the creep deformation and damage mechanisms are presented and discussed. The tested LPBF material exhibits a low defect population, which allows for the isolation and improved understanding of the effect of other typical aspects of an LPBF microstructure on the creep behavior. As a benchmark to assess the material properties of the LPBF 316L, a conventionally manufactured variant of 316L was also tested. To characterize the creep properties, hot tensile tests and constant force creep tests at 600 °C and 650 °C are performed. The creep stress exponents of the LPBF material are smaller than that of the conventional variant. The primary and secondary creep stages and the times to rupture of the LPBF material are shorter than the hot rolled 316L. Overall the creep damage is more extensive in the LPBF material. The creep damage of the LPBF material is overall mainly intergranular. It is presumably caused and accelerated by both the appearance of precipitates at the grain boundaries and the unfavorable orientation of the grain boundaries. Neither the melt pool boundaries nor entrapped gas pores show a significant influence on the creep damage mechanism. KW - 316L KW - Laser Powder Bed Fusion (LPBF) KW - Creep behavior KW - Additive Manufacturing KW - AGIL PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-539373 DO - https://doi.org/10.1016/j.msea.2021.142223 SN - 0921-5093 VL - 830 SP - 142223 PB - Elsevier B.V. AN - OPUS4-53937 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pauzon, C. A1 - Mishurova, Tatiana A1 - Fischer, M. A1 - Ahlström, J. A1 - Fritsch, Tobias A1 - Bruno, Giovanni A1 - Hryha, Eduard T1 - Impact of contour scanning and helium-rich process gas on performances of Alloy 718 lattices produced by laser powder bed fusion N2 - Contour scanning and process gas type are process parameters typically considered achieving second order effects compared to first order factors such as laser power and scanning speed. The present work highlights that contour scanning is crucial to ensure geometrical accuracy and thereby the high performance under uniaxial compression of complex Alloy 718 lattice structures. Studies of X-ray computed tomography visualizations of as-built and compression-strained structures reveal the continuous and smooth bending and compression of the walls, and the earlier onset of internal contact appearance in the denser lattices printed with contour. In contrast, the effect of addition of He to the Ar process gas appears to have limited influence on the mechanical response of the lattices and their microstructure as characterized by electron backscattered diffraction. However, the addition of He proved to significantly enhance the cooling rate and to reduce the amount of the generated spatters as evidenced by in situ monitoring of the process emissions, which is very promising for the process stability and powder reusability during laser powder bed fusion. KW - Additive manufacturing KW - Laser powder bed fusion KW - Gyroid lattice KW - Process atmosphere PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546632 DO - https://doi.org/10.1016/j.matdes.2022.110501 SN - 0264-1275 VL - 215 SP - 110501 PB - Elsevier Ltd. AN - OPUS4-54663 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - D'Accardi, E. A1 - Krankenhagen, Rainer A1 - Ulbricht, Alexander A1 - Pelkner, Matthias A1 - Pohl, Rainer A1 - Palumbo, D. A1 - Galietti, U. T1 - Capability to detect and localize typical defects of laser powder bed fusion (L‑PBF) process: an experimental investigation with different non‑destructive techniques N2 - Additive manufacturing (AM) technologies, generally called 3D printing, are widely used because their use provides a high added value in manufacturing complex-shaped components and objects. Defects may occur within the components at different time of manufacturing, and in this regard, non-destructive techniques (NDT) represent a key tool for the quality control of AM components in many industrial fields, such as aerospace, oil and gas, and power industries. In this work, the capability of active thermography and eddy current techniques to detect real imposed defects that are representative of the laser powder bed fusion process has been investigated. A 3D complex shape of defects was revealed by a μCT investigation used as reference results for the other NDT methods. The study was focused on two different types of defects: porosities generated in keyhole mode as well as in lack of fusion mode. Different thermographic and eddy current measurements were carried out on AM samples, providing the capability to detect volumetric irregularly shaped defects using non-destructive methods. KW - Additive Manufacturing KW - Defect detection KW - Thermography KW - Eddy-current testing KW - Micro-computed tomography PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546680 DO - https://doi.org/10.1007/s40964-022-00297-4 SN - 2363-9512 VL - 7 IS - 6 SP - 1239 EP - 1256 PB - Springer AN - OPUS4-54668 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Evans, Alexander A1 - Sprengel, Maximilian A1 - Ulbricht, Alexander A1 - Kromm, Arne A1 - Werner, Tiago A1 - Sommer, Konstantin A1 - Kelleher, Joe A1 - Mishurova, Tatiana A1 - Serrano Munoz, Itziar A1 - Fritsch, Tobias A1 - Schröder, Jakob A1 - Kannengießer, Thomas A1 - Bruno, Giovanni T1 - Manufacturing a safer world: Diffraction based residual stress analysis for metal additive manufacturing N2 - Metal Additive Manufacturing (AM) technologies such as Laser Powder Bed Fusion (LPBF) are characterized by layer wise construction, which enable advancements of component design, with associated potential gains in performance and efficiency. However, high magnitude residual stresses (RS) are often a product of the rapid thermal cycles typical of the layerwise process. Therefore, a deep understanding of the formation of RS, the influence of process parameters on their magnitude and the impact on mechanical performance is crucial for widespread application. The experimental characterisation of these RS is essential for safety related engineering application and supports the development of reliable numerical models. Diffraction-based methods for RS analysis using neutrons and high energy X-rays enable non-destructive spatially resolved characterisation of both surface and bulk residual stresses in complex components. This presentation will provide an overview of recent research by the BAM at large scale facilities for the characterization of residual stresses in LPBF metallic alloys as a function of process parameters. In addition, the challenges posed by the textured and hierarchical microstructures of LPBF materials on diffraction-based RS analysis in AM materials will be discussed. This will include the question of the d0 reference lattice spacing and the appropriate choice of the diffraction elastic constants (DECs) to calculate the level of RS in LPBF manufactured alloys. T2 - 11th INternational Conference on Residual Stress (ICRS11) CY - Online meeting DA - 28.03.2021 KW - Residual stress analysis KW - Neutron diffraction KW - X-ray diffraction KW - Additive manufacturing KW - Laser powder bed fusion KW - AGIL PY - 2022 AN - OPUS4-54676 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -