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 - CONF A1 - Schilling, Markus A1 - Niebergall, Ute A1 - Böhning, Martin T1 - Failure of PE-HD induced by liquid media (ESC) N2 - As the well-known damage mechanisms slow crack growth (SCG) and environmental stress cracking (ESC) are the major causes for possible failure of polyolefin-based materials, especially for PE-HD, they are highly relevant and need to be considered thoroughly. Furthermore, due to slight but perceptible differences in damaging effect, a differentiation between SCG and ESC is expedient. SCG appears in “inert” or “neutral” media without a decisive influence of the surrounding medium whereas ESC occurs in “active” media, which influence the failure behavior and time to failure crucially. To characterize the inherent resistance of the material against those damage mechanisms, the well-established Full-Notch Creep Test (FNCT) is used. In this study, the FNCT – usually applied according to ISO 16770 [3] using a few universal model liquid media and mainly for pipe materials – is extended by investigations with appropriate parameters of selected relevant PE-HD container materials also in real media, such as the topical fuels diesel and biodiesel. The investigations were performed using a novel FNCT-device with 12 individual sub-stations, each equipped with individual electronic stress and temperature control and continuous online monitoring of the specimen elongation. Especially, mechanical stress and temperature were varied systematically during FNCT and time to failure values, time-dependent elongation data as well as detailed fracture surface analysis by laser scanning microscopy (LSM) were combined for the first time (Fig. 1). Particularly, the fracture surface analysis provides a sound basis to characterize failure behavior, mainly regarding the balance between brittle crack propagation and ductile deformation. Therefore, fracture surface analysis is an essential tool for a decent assessment of SCG and ESC by FNCT measurements. T2 - 17th International Conference on Deformation, Yield and Fracture of Polymers (DYFP) CY - Kerkrade, The Netherlands DA - 25.03.2018 KW - Environmental stress cracking (ESC) KW - PE-HD KW - Full Notch Creep Test (FNCT) KW - Imaging techniques KW - Brittle / ductile fracture behavior KW - Crack propagation analysis PY - 2018 AN - OPUS4-44617 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schilling, Markus A1 - Marschall, Niklas A1 - Niebergall, Ute A1 - Böhning, Martin T1 - An optical criterion for the assessment of Full-Notch Creep Test (FNCT) fracture surfaces N2 - The full-notch creep test (FNCT) is a common method to evaluate the environmental stress cracking (ESC) behavior of high-density polyethylene (PE-HD) container materials . The test procedure as specified in ISO 16770 provides a comparative measure of the resistance against ESC using the time to failure of specimens mechanically loaded in a well-defined liquid environment. Since the craze-crack damage mechanism underlying the ESC process is associated with brittle failure, the occurrence of globally brittle fracture surfaces is a prerequisite to consider an FNCT measurement as representative for ESC . Therefore, an optical evaluation of FNCT fracture surfaces concerning their brittleness is essential. Due to the experimental setup, an inevitable increase of the true mechanical stress and the associated appearance of small ductile parts on fracture surfaces is induced in any case. Hence, an FNCT experiment is considered as 'valid', if the corresponding fracture surface is predominantly brittle . Based on laser scanning microscopy (LSM) height data of FNCT fracture surfaces , a universal and easy-to-use phenomenological criterion was developed to assess the validity of distinct FNCT experiments. This criterion is supposed to facilitate a quick evaluation of FNCT results in practical routine testing. T2 - PPS Europe-Africa 2019 Regional Conference (PPS 2019) CY - Pretoria, South Africa DA - 18.11.2019 KW - Full-Notch Creep Test (FNCT) KW - Polyethylene, PE-HD KW - Fracture surface analysis KW - Environmental stress cracking (ESC) KW - Optical criterion KW - Brittle fracture PY - 2019 AN - OPUS4-50940 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schilling, Markus A1 - Bayerlein, Bernd A1 - Schaarschmidt, J. A1 - von Hartrott, P. A1 - Bruns, M. A1 - Birkholz, H. A1 - Waitelonis, J. A1 - Hickel, Tilmann T1 - Seamless Science with the Platform MaterialDigital (PMD): Demonstration of Semantic Data Integration as Good Practices N2 - Following the new paradigm of materials development, design, and optimization, digitalization is the main goal in materials sciences and engineering (MSE) which imposes a huge challenge. In this respect, the quality assurance of processes and output data as well as the interoperability between applications following FAIR principles are to be ensured. For storage, processing, and querying of data in contextualized form, Semantic Web technologies (SWT) are used since they allow for machine-actionable and human-readable knowledge representations needed for data management, retrieval, and (re)use. The project ‘platform MaterialDigital’ (PMD) aims to bring together and support interested parties from both industrial and academic sectors in a sustainable manner in solving digitalization tasks and implementing digital solutions. Therefore, the establishment of a virtual material data space and the systematization of the handling of hierarchical, process-dependent material data are focused. Core points to be dealt with are the development of agreements on data structures and interfaces implemented in distinct software tools and to offer users specific support in their projects. Furthermore, the platform contributes to a standardized description of data processing methods in materials research. In this respect, selected MSE methods are semantically represented on a prototypical basis which are supposed to serve as best practice examples with respect to knowledge representation and the creation of knowledge graphs used for material data. Accordingly, this poster presentation illustrates demonstrators developed and deployed within the PMD project. Semantically anchored using the mid-level PMD Core Ontology (PMDco), they address data transformation leading to a novel data management which is based on semantic integrated data. The PMD data acquisition pipeline (DAP), which is fueled by traditional, diverse data formats, and a pipeline applying an electronic laboratory notebook (ELN) as data source are displayed. Additionally, the efficient combination of diverse datasets originating from different sources is demonstrated by the representation of a use case dealing with the well-known Orowan relation. T2 - 9. Dresdner Werkstoffsymposium CY - Dresden, Germany DA - 16.05.2024 KW - Semantic Data KW - Data Integration KW - Plattform MaterialDigital KW - Demonstrators KW - Electronic Lab Notebook PY - 2024 AN - OPUS4-60102 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schilling, Markus A1 - Bayerlein, Bernd A1 - Birkholz, H. A1 - von Hartrott, P. A1 - Waitelonis, J. A1 - Sack, H. T1 - PMDco - Platform MaterialDigital Core Ontology: Achieving High-Quality & Reliable FAIR Data N2 - Knowledge representation in the materials science and engineering (MSE) domain is a vast and multi-faceted challenge: Overlap, ambiguity, and inconsistency in terminology are common. Invariant and variant knowledge are difficult to align cross-domain. Generic top-level semantic terminology often is too abstract, while MSE domain terminology often is too specific. In this poster presentation, an approach how to maintain a comprehensive and intuitive MSE-centric terminology composing a mid-level ontology–the PMD core ontology (PMDco)–via MSE community-based curation procedures is shown. The PMDco is designed in direct support of the FAIR principles to address immediate needs of the global experts community and their requirements. The illustrated findings show how the PMDco bridges semantic gaps between high-level, MSE-specific, and other science domain semantics, how the PMDco lowers development and integration thresholds, and how to fuel it from real-world data sources ranging from manually conducted experiments and simulations as well as continuously automated industrial applications. T2 - DVM Arbeitskreis Betriebsfestigkeit - Potenziale der Betriebsfestigkeit in Zeiten des technologischen und gesellschaftlichen Wandels CY - Munich, Germany DA - 11.10.2023 KW - Digitalization KW - Semantic Web Technologies KW - FAIR KW - Data Interoperability KW - PMD Core Ontology PY - 2023 AN - OPUS4-58602 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schilling, Markus A1 - Bayerlein, Bernd A1 - Birkholz, H. A1 - Hanke, T. A1 - Waitelonis, J. A1 - Sack, H. T1 - PMDco: Achieving High-Quality & Reliable FAIR Data N2 - Knowledge representation in the materials science and engineering (MSE) domain is a vast and multi-faceted challenge: Overlap, ambiguity, and inconsistency in terminology are common. Invariant and variant knowledge are difficult to align cross-domain. Generic top-level semantic terminology often is too abstract, while MSE domain terminology often is too specific. In this presentation, an approach how to maintain a comprehensive and intuitive MSE-centric terminology composing a mid-level ontology–the PMD core ontology (PMDco)–via MSE community-based curation procedures is shown. The PMDco is designed in direct support of the FAIR principles to address immediate needs of the global experts community and their requirements. The illustrated findings show how the PMDco bridges semantic gaps between high-level, MSE-specific, and other science domain semantics, how the PMDco lowers development and integration thresholds, and how to fuel it from real-world data sources ranging from manually conducted experiments and simulations as well as continuously automated industrial applications. T2 - Kupfer-Symposium CY - Jena, Germany DA - 29.11.2023 KW - Ontology KW - Semantic Web Technologies KW - Plattform MaterialDigital KW - PMDco PY - 2023 AN - OPUS4-59031 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Scheffler, F. A1 - Tielemann, Christopher A1 - Busch, R. A1 - Kober, M. A1 - Müller, Ralf A1 - Brauer, D. S. T1 - Crystallization of glasses studied with PEEM N2 - A heat treated glass that formed crystals under controlled conditions can be a glass ceramic. A proper understanding of crystallization in glassy melts is needed yet still lacking. Involved processes include the mobility of Elements within the glass during heat treatment and the reorganization of atomic bonds during crystallization. This change in coordination number of certain elements is easily observable in bulk glass samples during heat treatment with XAS. Our plan was to monitor these reorganization processes in situ at the immediate surface during heat treatment with PEEM to get time and spatial resolved data. T2 - Joint Meeting of the Polish Synchrotron Radiation Society and SOLARIS Users CY - Online meeting DA - 09.09.2020 KW - Glass KW - Surface KW - Peem KW - Synchrotron PY - 2020 AN - OPUS4-51336 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Scheffler, F. A1 - Fleck, M. A1 - Santiago, C. F. A1 - Brauer, D. S. A1 - Müller, Ralf T1 - Morphologies of Fresnoite surface crystals of BT0.75S glass under different atmospheric conditions N2 - Fresnoite glass-ceramics are characterized by piezoelectric, pyroelectric and non-linear optical properties. These properties can be adjusted by orienting the fresnoite crystals during crystallization. Crystallization begins at the surface. The first surface crystals are not oriented perpendicular and, therfore, produce a surface layer that has not the intended properties. To overcome this issue, the formation of fresnoite surface crystals at different atmospheric conditions was studied. T2 - 9th Int. Otto Schott Colloquium CY - Jena, Germany DA - 09.09.2019 KW - Glass KW - Surface crystallization KW - Crystal orientation PY - 2019 AN - OPUS4-50460 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Saber, Yassin A1 - Zocca, Andrea A1 - Günster, Jens T1 - Fully automated and decentralized fused filament fabrication of ceramics for remote applications N2 - Manufacturing of ceramic components in remote (i.e., geographically isolated) settings poses significant challenges where access to conventional manufacturing facilities is limited or non-existent. Fused Filament Fabrication (FFF) enables the rapid manufacturing of ceramic components with complex geometries. Parts formed by FFF require subsequent debinding and sintering to reach full density. Debinding and sintering are typically executed in separate steps with different equipment, necessitating extensive human handling which hinders process automation and may be challenging for the operator in isolated environments. This poster presents an innovative approach: the integration of all process steps into a single, fully automated system, streamlining the process and minimizing human involvement. Our system combines a dual extrusion filament printer with a porous and heat-resistant ceramic print bed. The porous print bed enables mechanical interlocking of the first printed layers, ensuring adhesion and structural integrity during FFF. Ceramic parts are printed onto thin sacrificial rafts, which are built using an interface material with the same binder as the ceramic filament. After the print is completed, the heat-resistant print bed with all parts is transferred seamlessly with a carrier system into a high-temperature furnace for debinding and sintering. During sintering the sacrificial raft is disintegrated, allowing for unconstrained sintering of the ceramic parts and easy removal of the finished parts. In conclusion, our integrated approach enables significant advancements in the fabrication of complex ceramic components in remote environments with increased efficiency and minimal human handling. T2 - yCAM 2024 CY - Tampere, Finnland DA - 06.05.2024 KW - Fused Filament Fabrication PY - 2024 AN - OPUS4-60057 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Röhsler, Andreas A1 - Sobol, Oded A1 - Nolze, Gert A1 - Böllinghaus, Thomas A1 - Unger, Wolfgang T1 - Analysis of deuterium in austenitic stainless steel AISI 304L by Time-of-Flight Secondary Ion Mass Spectrometry N2 - Due to their excellent combination of ductility, strength and corrosive resistance, austenitic stainless steels (ASS) are widely used in many industrial applications. Thus, these steel grades can be found as structural components in the (petro-)chemical industry, in offshore applications and more recent for storage and transport of hydrogen fuel. Steels employed for these applications are exposed to aggressive environments and hydrogen containing media. The ingress and accumulation of hydrogen into the microstructure is commonly observed during service leading to a phenomenon called “hydrogen embrittlement”. A loss in ductility and strength, the formation of cracks and phase transformations are typical features of this hydrogen-induced degradation of mechanical properties. Although, great efforts are made to understanding hydrogen embrittlement, there is an ongoing debate of the underlying mechanisms. This knowledge is crucial for the safe use and durability of components on the one side and the development of new materials on the other. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) was proven to be a powerful tool for depicting the distribution of the hydrogen isotope deuterium in the microstructure of austenitic and duplex steels. The combination with imaging techniques such as electron backscatter diffraction (EBSD) and scanning electron microscopy (SEM), delivering structural and morphological information, creates a comprehensive picture of the hydrogen/deuterium-induced effects in the materials. All the gathered data is treated with principal component analysis (PCA) and data fusion to enhance the depth of information. The mobility of hydrogen and deuterium in a steel microstructure is affected by external mechanical stress. To investigate the behaviour of deuterium in a strained microstructure, a new in situ experimental approach was developed. This gives the possibility of analysing samples in the SIMS instrument simultaneously to four-point-bending-tests. Specimens made from ASS AISI 304L were electrochemically charged with deuterium instead of hydrogen. This necessity stems from the difficulty to separate between artificially charged hydrogen and hydrogen existing in the pristine material or adsorbed from the rest gas in the analysis chamber. Nonetheless, similar diffusion, permeation and solubility data allow to draw qualitative conclusions from the experiments, which are relevant for the application addressed. T2 - SIMS Europe 2018 CY - Münster, Germany DA - 16.09.2018 KW - Hydrogen KW - Deuterium KW - Austenitic stainless steel KW - SIMS PY - 2018 AN - OPUS4-46029 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -