TY - CONF A1 - Schilling, Markus T1 - Seamless Science in 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 - Materials Science and Engineering Congress 2024 CY - Darmstadt, Germany DA - 24.09.2024 KW - Semantic Data KW - Data Integration KW - Digitalization KW - Demonstrators PY - 2024 AN - OPUS4-61136 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Holzer, Marco A1 - Johansen, Sidsel M. A1 - Christensen, Johan F.S. A1 - Smedskjaer, Morten M. A1 - Cicconi, Maria Rita A1 - de Ligny, Dominique A1 - Müller, Ralf A1 - de Camargo, Andrea S.S. A1 - Maaß, Robert T1 - Direct connection between secondary relaxation mode and fracture toughness in alkali-aluminosilicate glasses N2 - Oxide glasses are intrinsically brittle, lacking sufficient atomic-scale mechanisms that can relax mechanical stresses in the vicinity of a propagating crack. As a result, fracture is typically well-captured by considering local bond rupture at the crack tip. Here we demonstrate that barrier energies related to the low-temperature 𝛾-relaxation mode in alkali-aluminosilicate glasses are inversely related to the fracture toughness measured via standardized three-point bending fracture experiments. This holds true for both a series with varying cations (Li, Na, K) and one with varying Li concentration. The structural rationale for this finding is gained via Raman spectroscopy. The findings suggest that a fundamental structural relaxation mode measured on bulk specimens can serve as an effective guideline for fracture toughness of oxide glasses. Data for additional silicate glasses support this conclusion. KW - Fracture toughness KW - Oxide glass KW - Mechanical properties KW - Alkali-aluminosilicate glasses KW - Internal friction PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-651540 DO - https://doi.org/10.1016/j.mtadv.2025.100669 SN - 2590-0498 VL - 29 SP - 1 EP - 10 PB - Elsevier Ltd. CY - Amsterdam, Niederlande AN - OPUS4-65154 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Moschetti, Michael A1 - Lemiasheuski, Anton A1 - Bajer, Evgenia A1 - Porohovoj, Ilja A1 - Göbel, Artur A1 - Pfennig, Anja A1 - Bettge, Dirk A1 - Maaß, Robert T1 - Robot-Assisted Automated Serial-Sectioning and Imaging for 3D Microstructural Investigations N2 - Comprehensive materials characterization requires precise structural knowledge beyond traditional methods. The robot-assisted automated serial-sectioning and imaging (RASI) platform, developed at BAM, provides automated 3D metallographic reconstructions, enabling detailed microstructural analysis of technical materials. This article showcases RASI’s capabilities through several case studies, including characterization of lamellar graphite in gray cast iron, porosity in sintered steel, melt pool morphology in additively manufactured 316L stainless steel, defects in metal-ceramic packages, and oxidation behavior in an Fe-12Cr-2Co alloy. By automating sample handling, mechanical serial-sectioning, etching, and optical imaging, RASI captures complex 3D microstructures with high precision and at high speed. This approach reveals microstructural features missed by 2D analysis, even using stereological assumptions. Specifically, statistically rare and large microstructural features, such as secondary phases or interconnected pores, become apparent, which 2D methods cannot reveal. The generated volumetric data can furthermore serve as quantitative reference datasets (i.e., the ‘ground truth’) essential for validating other 3D characterization techniques and computational models, helping to bridge the gap between predictive simulations and real-world material behavior. RASI’s modular design makes it a flexible tool that provides realistic 3D insights into materials, which can be used for advanced materials research, process optimization, and quality control. KW - 3D metallography KW - Automated microstructure characterization KW - Image segmentation KW - Mechanical polishing based serial-sectioning KW - Process-microstructure-property relationships KW - Quantitative microstructure PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-649614 DO - https://doi.org/10.1002/adem.202502202 SN - 1527-2648 VL - 28 IS - 2 SP - 1 EP - 14 PB - Wiley-VCH GmbH AN - OPUS4-64961 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ikeda, Yuki A1 - Wallis, Theophilus A1 - Maaß, Robert A1 - Darvishi Kamachali, Reza T1 - Thermodynamics of grain boundary segregation transition and their relevance for liquid metal embrittlement in Fe-Zn system N2 - Grain boundaries (GBs) are common sites of failure in polycrystalline materials. Recently, a massive Zn segregation transition at Fe GBs was discovered and shown to act as a potent precursor of liquid metal embrittlement (LME) in the Fe-Zn system (Kamachali et al., Scripta Materialia 238 (2024) 115758). In this study, we elaborate on how temperature, GB type and the chemo-structurally coupled phase decomposition at the GB impact this segregation transition. CALPHAD and atomistic simulation data were utilized as inputs to conduct quantitative density-based thermodynamic modeling and phase-field simulations across various GBs, alloy compositions, and temperatures. We reveal that once the segregation transition becomes possible, the GB structural variation stabilizes spinodally formed Zn-rich phases within the GB region, with a higher tendency in disordered GBs. GB phase diagrams were constructed to identify and analyze the range of critical temperatures and alloy compositions associated with the segregation transition. The phase diagrams reveal that the miscibility gap for more disordered GB expands and, although the segregation transition is inevitable and occurs for all GBs, the barrier to triggering it is lower for more disordered GBs. Based on our thermodynamic analyses, potential processing modifications and GB engineering strategies for mitigating segregation-induced LME are thoroughly discussed. KW - Thermodynamics KW - Phase-Field Modelling KW - Steels PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-634145 DO - https://doi.org/10.1016/j.actamat.2025.121134 SN - 1359-6454 VL - 296 SP - 1 EP - 11 PB - Elsevier BV AN - OPUS4-63414 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Chang, Yen-Ting A1 - Sharda, Abhi A1 - Rosalie, Julian M. A1 - Maaß, Robert A1 - Charpagne, Marie A. T1 - A bcc refractory high-entropy alloy: the ideal case of smooth plastic flow N2 - Single crystalline metals exhibit correlated dislocation dynamics, irrespective of lattice system. This collective evolution of dislocation structures is intermittent and scale-free, implying divergent length scales that play a critical role in failure initiation and therefore microstructural design. Here we report on a HfNbTaTiZr refractory high-entropy alloy, that lacks criticality in the collective dislocation response. This unusual behaviour manifests itself in almost quenched-out microplastic stress-strain fluctuations and sluggish dislocation avalanching, otherwise only seen in complex engineering alloys. These findings demonstrate how the high-entropy paradigm can serve as a role model to effectively suppress unwanted plastic fluctuations in metals deformation. KW - Plasticity KW - Dislocations KW - Avalanches KW - Refractory high-entropy alloys PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630241 DO - https://doi.org/10.1080/21663831.2025.2497860 SN - 2166-3831 SP - 1 EP - 8 PB - Taylor & Francis Group AN - OPUS4-63024 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dudziak, Mateusz A1 - Riechers, Birte A1 - Maaß, Robert A1 - Michalchuk, Adam A1 - Schönhals, Andreas A1 - Szymoniak, Paulina T1 - Beyond conventional calorimetry: Unlocking thermal characterization with fast scanning techniques N2 - Fast scanning calorimetry (FSC) has emerged as a transformative technique in thermal analysis, enabling the investigation of rapid and kinetically driven thermal transitions that are inaccessible to conventional differential scanning calorimetry. This review highlights the capabilities enabled by FSC for studying a wide range of materials under extreme thermal conditions, including polymers, pharmaceuticals, metallic glasses, nanocomposites, and hydrogels. By employing ultrafast heating and cooling rates, FSC allows for the suppression of crystallization, resolution of weak transitions, and analysis of thermally labile or size-limited samples. The technique is particularly valuable for probing glass transitions, relaxation phenomena, and phase behavior in systems with complex morphologies or confined geometries. Case studies demonstrate the use of FSC in characterizing vitrification, physical aging, and interfacial dynamics, as well as its application in emerging fields such as additive manufacturing, supramolecular systems, and neuromorphic materials. Together, these examples underscore the role that FSC plays in advancing the understanding of structure-property relationships across diverse material classes. KW - Flash DSC KW - Calorimetry KW - Glass transition PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-647405 DO - https://doi.org/10.1016/j.tca.2025.180177 VL - 754 SP - 1 EP - 14 PB - Elsevier B.V. AN - OPUS4-64740 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Qu, R. A1 - Maaß, Robert A1 - Liu, Z. A1 - Tönnies, D. A1 - Tian, L. A1 - Ritchie, R. A1 - Zhang, Z. A1 - Volkert, A. T1 - Flaw-insentive fracture of a micrometer-sized brittle metallic glass N2 - Brittle materials, such as oxide glasses, are usually very sensitive to flaws, giving rise to a macroscopic fracture strength that is much lower than that predicted by theory. The same applies to metallic glasses (MGs), with the important difference that these glasses can exhibit certain plastic strain prior to catas- trophic failure. Here we consider the strongest metallic alloy known, a ternary Co 55 Ta 10 B 35 MG. We show that this macroscopically brittle glass is flaw-insensitive at the micrometer scale. This discovery emerges when testing pre-cracked specimens with self-similar geometries, where the fracture stress does not de- crease with increasing pre-crack size. The fracture toughness of this ultra-strong glassy alloy is further shown to increase with increasing sample size. Both these findings deviate from our classical under- standing of fracture mechanics, and are attributed to a transition from toughness-controlled to strength- controlled fracture below a critical sample size. KW - Metallic glass KW - Fracture toughness KW - Size effect KW - Small-scale PY - 2021 DO - https://doi.org/10.1016/j.actamat.2021.117219 VL - 218 PB - Elsevier Ltd. AN - OPUS4-53097 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Maaß, Robert T1 - Structural dynamics in metallic glasses due to Thermal and Mechanical Stress N2 - This talk addresses aging induced property changes of metallic glasses. Priority is given thermally and mechanically induced structural changes, of which the time-dependent dynamics is tracked using coherent scattering. Strong intermittency is observed and accelerated transport is seen at the smallest applied stresses. These findings have significant implications for how metallic glass components respond in realistic service conditions. T2 - Seminar Universität Münster 2020 CY - Münster, Germany DA - 01.12.2020 KW - Metallic glasses KW - Structure PY - 2020 AN - OPUS4-60714 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Liu, C. A1 - Ikeda, Yuki A1 - Maaß, Robert T1 - Strain-dependent shear-band structure in a Zr-based bulk metallic glass N2 - This work presents strong evidence for structural damage accumulation as a function of shear strain admitted by shear bands in a Zr-based bulk metallic glass. Analyzing the shear-band structure of shear- band segments that experienced shear strains covering four orders of magnitude with high-angle annular dark field transmission electron microscopy (HAADF-STEM) reveals strongly scattered data with on overall trend of increasing local volume dilatation with increasing shear strain. Locally, however, a variety of trends is observed, which underlines the strong heterogeneity of structural damage in shear bands in metallic glasses. KW - Transmission electron microscopy KW - Metallic glass KW - Shear bands KW - Shear-band structure KW - Shear strain PY - 2021 DO - https://doi.org/10.1016/j.scriptamat.2020.08.030 VL - 190 SP - 75 EP - 79 PB - Elsevier Ltd. AN - OPUS4-52454 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Holzer, Marco T1 - Glass fracture surface energy calculated from crystal structure and bond-energy data N2 - Enhancing the fracture toughness is still one of the major challenges in the field of oxide glasses. To screen different glass systems for promising candidates, a theoretical expression for the fracture surface energy, G, linked to the fracture toughness, KIc, is thus of interest. Extending our earlier work on nucleation and surface energies [1], we present a simple approach for predicting the fracture surface energy of oxide glasses, G using readily available crystallographic structure data and diatomic bond energies. The proposed method assumes that G of glass equals the surface fracture energy of the weakest fracture (cleavage) plane of the isochemical crystal. For non-isochemically crystallizing glasses, an average G is calculated from the weighed fracture energy data of the constitutional crystal phases according to Conradt [2]. Our predictions yield good agreement with the glass density- and chemical bond energy-based prediction model of Rouxel [3] and with experimentally obtained G values known at present. [1] C. Tielemann, S. Reinsch, R. Maass, J. Deubener, R. Müller, J. Non-Cryst. Solids 2022, 14, 100093 [2] R. Conradt, J. Non-Cryst. Solids 2004, 345-346, 16 [3] R., Tanguy, Scripta Materialia 2017, 109-13, 137 T2 - DPG Spring Meeting of the Condensed Matter Section CY - Dresden, Germany DA - 26.03.2023 KW - Fracture Toughness KW - Oxide Glasses KW - Surface Energy PY - 2023 AN - OPUS4-58414 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bayerlein, Bernd A1 - Waitelonis, Jörg A1 - Birkholz, Henk A1 - Jung, Matthias A1 - Schilling, Markus A1 - v. Hartrott, Philipp A1 - Bruns, Marian A1 - Schaarschmidt, Jörg A1 - Beilke, Kristian A1 - Mutz, Marcel A1 - Nebel, Vincent A1 - Königer, Veit A1 - Beran, Lisa A1 - Kraus, Tobias A1 - Vyas, Akhilesh A1 - Vogt, Lars A1 - Blum, Moritz A1 - Ell, Basil A1 - Chen, Ya‐Fan A1 - Waurischk, Tina A1 - Thomas, Akhil A1 - Durmaz, Ali Riza A1 - Ben Hassine, Sahar A1 - Fresemann, Carina A1 - Dziwis, Gordian A1 - Beygi Nasrabadi, Hossein A1 - Hanke, Thomas A1 - Telong, Melissa A1 - Pirskawetz, Stephan A1 - Kamal, Mohamed A1 - Bjarsch, Thomas A1 - Pähler, Ursula A1 - Hofmann, Peter A1 - Leemhuis, Mena A1 - Özçep, Özgür L. A1 - Meyer, Lars‐Peter A1 - Skrotzki, Birgit A1 - Neugebauer, Jörg A1 - Wenzel, Wolfgang A1 - Sack, Harald A1 - Eberl, Chris A1 - Portella, Pedro Dolabella A1 - Hickel, Tilmann A1 - Mädler, Lutz A1 - Gumbsch, Peter T1 - Concepts for a Semantically Accessible Materials Data Space: Overview over Specific Implementations in Materials Science N2 - This article describes advancements in the ongoing digital transformation in materials science and engineering. It is driven by domain‐specific successes and the development of specialized digital data spaces. There is an evident and increasing need for standardization across various subdomains to support science data exchange across entities. The MaterialDigital Initiative, funded by the German Federal Ministry of Education and Research, takes on a key role in this context, fostering collaborative efforts to establish a unified materials data space. The implementation of digital workflows and Semantic Web technologies, such as ontologies and knowledge graphs, facilitates the semantic integration of heterogeneous data and tools at multiple scales. Central to this effort is the prototyping of a knowledge graph that employs application ontologies tailored to specific data domains, thereby enhancing semantic interoperability. The collaborative approach of the Initiative's community provides significant support infrastructure for understanding and implementing standardized data structures, enhancing the efficiency of data‐driven processes in materials development and discovery. Insights and methodologies developed via the MaterialDigital Initiative emphasize the transformative potential of ontology‐based approaches in materials science, paving the way toward simplified integration into a unified, consolidated data space of high value. KW - Semantic Interoperability KW - Data Spaces KW - Integration Workflows KW - MaterialDigital PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-622952 DO - https://doi.org/10.1002/adem.202401092 SN - 1527-2648 SP - 1 EP - 25 PB - Wiley-VCH CY - Weinheim AN - OPUS4-62295 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bekemeier, Simon A1 - Caldeira Rêgo, C. R. A1 - Mai, H. L. A1 - Sikia, Ujjal A1 - Waseda, O. A1 - Apel, M. A1 - Arendt, F. A1 - Aschemann, A. A1 - Bayerlein, Bernd A1 - Courant, R. A1 - Dziwis, G. A1 - Fuchs, F. A1 - Giese, U. A1 - Junghanns, K. A1 - Kamal, M. A1 - Koschmieder, L. A1 - Leineweber, S. A1 - Luger, M. A1 - Lukas, M. A1 - Maas, J. A1 - Mertens, J. A1 - Mieller, Björn A1 - Overmeyer, L. A1 - Pirch, N. A1 - Reimann, J. A1 - Schröck, S. A1 - Schulze, P. A1 - Schuster, J. A1 - Seidel, A. A1 - Shchyglo, O. A1 - Sierka, M. A1 - Silze, F. A1 - Stier, S. A1 - Tegeler, M. A1 - Unger, Jörg F. A1 - Weber, M. A1 - Hickel, Tilmann A1 - Schaarschmidt, J. T1 - Advancing Digital Transformation in Material Science: The Role of Workflows Within the MaterialDigital Initiative N2 - The MaterialDigital initiative represents a major driver toward the digitalization of material science. Next to providing a prototypical infrastructure required for building a shared data space and working on semantic interoperability of data, a core focus area of the Platform MaterialDigital (PMD) is the utilization of workflows to encapsulate data processing and simulation steps in accordance with findable, accessible, interoperable, and reusable principles. In collaboration with the funded projects of the initiative, the workflow working group strives to establish shared standards, enhancing the interoperability and reusability of scientific data processing steps. Central to this effort is the Workflow Store, a pivotal tool for disseminating workflows with the community, facilitating the exchange and replication of scientific methodologies. This article discusses the inherent challenges of adapting workflow concepts, providing the perspective on developing and using workflows in the respective domain of the various funded projects. Additionally, it introduces the Workflow Store’s role within the initiative and outlines a future roadmap for the PMD workflow group, aiming to further refine and expand the role of scientific workflows as a means to advance digital transformation and foster collaborative research within material science. KW - Digitalisation KW - FAIR principles KW - MaterialDigital KW - Scientific workflows KW - Semantic interoperability PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624088 DO - https://doi.org/10.1002/adem.202402149 SN - 1527-2648 IS - 2402149 SP - 1 EP - 25 PB - Wiley-VCH GmbH AN - OPUS4-62408 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Chen, Yu A1 - Bo, Zhen-Xing A1 - Zhou, Hong Bo A1 - Sun, Bao-An A1 - Sun, Yong Hao A1 - Maaß, Robert A1 - Wang, Wei Hua T1 - Nanoindentation reveals universal scaling of pop-in plasticity in metallic glasses N2 - Plastic flow of metallic glasses proceeds intermittently in the inhomogeneous deformation regime. Mediated via shear bands, quasi-static straining gives rise to plastic instabilities that are measured as abrupt displacement bursts or pop-ins. The latter is a well-known feature in nanoindentation, where its first occurrence probes the critical and site-specific stress of nano-scale incipient shear deformation. Here we show that the statistical distribution of the stress and magnitude of the first shear instability, as well as its successive higher-order events, universally follow Weibull statistics across ten different metallic glasses. This indicates a fundamentally identical plastic process across glass-forming alloys and progressing deformation that is governed by a weakest-link phenomenon. This finding stands in strong contrast to crystalline alloys, where both defect nucleation and defect-structure evolution control shear instabilities and depend on the deformation history. KW - Metallic glasses KW - Nanoindentation KW - Intermittent flow KW - Pop-ins KW - Weibull distribution PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624772 DO - https://doi.org/10.1016/j.scriptamat.2025.116549 VL - 259 SP - 1 EP - 5 PB - Elsevier Inc. AN - OPUS4-62477 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Riechers, Birte A1 - Das, Amlan A1 - Rashidi, Reza A1 - Dufresne, Eric A1 - Maaß, Robert T1 - Metallic glasses: Elastically stiff yet flowing at any stress N2 - Crystalline solids have a minimum stress needed to displace atoms or to move defects. This stress defines the true elastic limit and is generally a sizeable share of the macroscopic yield stress. Here we demonstrate that a metallic glass, an amorphous solid with a yield stress in the giga-pascal regime, lacks such a true microscopic elastic limit. Leveraging in-situ coherent x-ray scattering, we uncover a strongly accelerated atomic-scale transport upon the application of a stress as small as 0.005 times the yield stress. With increasing stress levels, the distribution of structural relaxation times changes from compressed exponential to simple exponential form, revealing a stress–temperature equivalence in the time-scale domain. These findings strongly promote a microstructurally heterogeneous picture of metallic glasses, in which a part of the amorphous microstructure controls macroscopic yielding whereas another part admits microplastic flow at any stress. KW - Metallic glasses KW - Microstructure PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624530 DO - https://doi.org/10.1016/j.mattod.2024.11.015 VL - 82 SP - 92 EP - 98 PB - Elsevier B.V. AN - OPUS4-62453 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Hickel, Tilmann A1 - Richter, Silke A1 - Bitzek, E. A1 - Ávila Calderón, Luis A1 - Gedsun, A. A1 - Forti, M. A1 - Hammerschmidt, T. A1 - Olbricht, Jürgen A1 - Skrotzki, Birgit T1 - NFDI-MatWerk/IUC02 Definition for Reference Data of Materials N2 - This definition was agreed within the infrastructure use case IUC02 “Framework for curation and distribution of reference datasets” of the consortium NFDI-MatWerk. It is broadly formulated to cover experimental and simulation MSE data and will be developed further in agreement with the MSE community. KW - Referenzdaten KW - Digitalisierung KW - NFDI-MatWerk KW - Research Data Management KW - Reference Data PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-611688 DO - https://doi.org/10.5281/zenodo.11667673 PB - Zenodo CY - Geneva AN - OPUS4-61168 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fareed, Adnan A1 - Rosalie, Julian A1 - Kar, Satyakam A1 - Fähler, Sebastian A1 - Maaß, Robert T1 - Small-scale functional fatigue of a Ni-Mn-Ga Heusler alloy N2 - Functional fatigue of shape-memory alloys is a considerable threat to the reliable service of actuation devices. Here, we demonstrate the essentially degradation-free cyclic phase-transformation behavior of Ni-Mn-Ga microcrystals up to one million stress-driven superelastic cycles. Cyclic dissipation amounts to about 1/5 of the bulk counterpart and remains unaffected during cycling, even after the introduction of dislocation structures via plastic straining. Plastic yielding and the transformation stress largely exceed the known bulk values. However, the transformation-stress is found to depend on plastic pre-straining, which suggests that the size-affected transformation stress is sensitive to the initial defect structure and that it can be tuned by a targeted introduction of dislocations. These findings demonstrate the high suitability of Ni-Mn-Ga as a robust shape-memory alloy in small-scale functional device engineering. KW - Superelasticity KW - Shape-memory alloys KW - Functional fatigue KW - Ni-Mn-Ga PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600695 DO - https://doi.org/10.1016/j.actamat.2024.119988 VL - 274 SP - 1 EP - 10 PB - Elsevier B.V. AN - OPUS4-60069 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Riechers, Birte A1 - Das, Amlan A1 - Dufresne, Eric A1 - Derlet, Peter M. A1 - Maaß, Robert T1 - Intermittent cluster dynamics and temporal fractional diffusion in a bulk metallic glass N2 - Glassy solids evolve towards lower-energy structural states by physical aging. This can be characterized by structural relaxation times, the assessment of which is essential for understanding the glass’ time-dependent property changes. Conducted over short times, a continuous increase of relaxation times with time is seen, suggesting a time-dependent dissipative transport mechanism. By focusing on micro-structural rearrangements at the atomic-scale, we demonstrate the emergence of sub-diffusive anomalous transport and therefore temporal fractional diffusion in a metallic glass, which we track via coherent x-ray scattering conducted over more than 300,000 s. At the longest probed decorrelation times, a transition from classical stretched exponential to a power-law behavior occurs, which in concert with atomistic simulations reveals collective and intermittent atomic motion. Our observations give a physical basis for classical stretched exponential relaxation behavior, uncover a new power-law governed collective transport regime for metallic glasses at long and practically relevant time-scales, and demonstrate a rich and highly non-monotonous aging response in a glassy solid, thereby challenging the common framework of homogeneous aging and atomic scale diffusion. KW - Glassy solids KW - Fractional diffusion KW - Coherent x-ray scattering PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-608015 DO - https://doi.org/10.1038/s41467-024-50758-3 VL - 15 IS - 1 SP - 1 EP - 9 PB - Springer Science and Business Media LLC AN - OPUS4-60801 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fareed, Adnan A1 - Rosalie, Julian A1 - Kumar, Sourabh A1 - Kar, S. A1 - Hickel, Tilmann A1 - Fähler, S. A1 - Maaß, Robert T1 - Constrained incipient phase transformation in Ni-Mn-Ga films: A small-scale design challenge N2 - Ni-Mn-Ga shape-memory alloys are promising candidates for large strain actuation and magnetocaloric cooling devices. In view of potential small-scale applications, we probe here nanomechanically the stress-induced austenite–martensite transition in single crystalline austenitic thin films as a function of temperature. In 0.5 μm thin films, a marked incipient phase transformation to martensite is observed during nanoindentation, leaving behind pockets of residual martensite after unloading. These nanomechanical instabilities occur irrespective of deformation rate and temperature, are Weibull distributed, and reveal large spatial variations in transformation stress. In contrast, at a larger film thickness of 2 μm fully reversible transformations occur, and mechanical loading remains entirely smooth. Ab-initio simulations demonstrate how an in-plane constraint can considerably increase the martensitic transformation stress, explaining the thickness-dependent nanomechanical behavior. These findings for a shape-memory Heusler alloy give insights into how reduced dimensions and constraints can lead to unexpectedly large transformation stresses that need to be considered in small-scale actuation design. KW - Shape-memory alloys KW - Nanoindentation KW - Incipient plasticity KW - NiMaGa PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-581422 DO - https://doi.org/10.1016/j.matdes.2023.112259 VL - 233 SP - 1 EP - 8 PB - Elsevier B.V. AN - OPUS4-58142 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wang, Zengquan A1 - Riechers, Birte A1 - Derlet, Peter M. A1 - Maaß, Robert T1 - Atomic cluster dynamics causes intermittent aging of metallic glasses N2 - In the past two decades, numerous relaxation or physical aging experiments of metallic glasses have revealed signatures of intermittent atomic-scale processes. Revealed via intensity cross-correlations from coherent scattering using X-ray photon correlation spectroscopy (XPCS), the observed abrupt changes in the time-domain of atomic motion does not fit the picture of gradual slowing down of relaxation times and their origin continues to remain unclear. Using a binary Lennard-Jones model glass subjected to microsecond-long isotherms, we show here that temporally and spatially heterogeneous atomic-cluster activity at different length-scales drive the emergence of highly non-monotonous intensity cross-correlations. The simulated XPCS experiments reveal a variety of time-dependent intensity-cross correlations that, depending on both the structural evolution and the 𝑞-space sampling, give detailed insights into the possible structural origins of intermittent aging measured with XPCS. KW - Metallic glasses KW - Aging KW - Molecular dynamics KW - XPCS PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595415 DO - https://doi.org/10.1016/j.actamat.2024.119730 SN - 1359-6454 VL - 267 SP - 1 EP - 9 PB - Elsevier B.V. CY - Amsterdam, Niederlande AN - OPUS4-59541 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fantin, Andrea A1 - Manzoni, Anna Maria A1 - Springer, H. A1 - Darvishi Kamachali, Reza A1 - Maaß, Robert T1 - Local lattice distortions and chemical short-range order in MoNbTaW N2 - Extended X-ray absorption fine structure (EXAFS) conducted on an equiatomic MoNbTaW bcc medium-entropy alloy that was annealed at 2273 K reveals unexpectedly small 1st and 2nd shell element-specific lattice distortions. An experimental size-mismatch parameter, δexp, is determined to be ca. 50% lower than the corresponding calculated value. Around W, short-range order (SRO) preferring 4d elements in the 1st and 2nd shells persists. A Nb-W ordering is found, which is reminiscent of ordering emerging at lower temperatures in the B2(Mo,W;Ta,Nb)- and B32(Nb,W)-phases. With high-temperature ordering preferences in fcc also foreshadowing low-temperature phase, these findings suggest a general feature of high-temperature SRO. KW - High Entropy Alloys KW - Short-range order KW - Lattice distortions KW - EXAFS PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-598164 DO - https://doi.org/10.1080/21663831.2024.2326014 SN - 2166-3831 VL - 12 IS - 5 SP - 346 EP - 354 PB - Taylor & Francis AN - OPUS4-59816 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rashidi, Reza A1 - Riechers, Birte A1 - Rosalie, Julian A1 - Maaß, Robert T1 - Annealing-dependent elastic microstructure in a Zr-based metallic glass N2 - In this letter, we demonstrate the robust presence of an elastic microstructure in a Zr-based metallic glass (MG) with a characteristic length-scale of the order of 100 nm. This length scale increases systematically towards the MG surface in differently sized casts, whereas thermal relaxation homogenizes both the internal length-scale gradient and the magnitude of the elastic fluctuations. Strongest changes during relaxation arise in the stiffest parts of the elastic microstructure. These findings indicate that the elastic microstructure emerges due to cooling constraints and may therefore be a microstructural manifestation of the internal residual stresses that arise during MG-solidification. KW - Metallic glass KW - Heterogeneity KW - Elastic microstructure KW - Nanoindentation PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-610962 DO - https://doi.org/10.1016/j.scriptamat.2024.116380 VL - 255 SP - 1 EP - 5 PB - Elsevier B.V. CY - Amsterdam, Niederlande AN - OPUS4-61096 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hoffmann, M. A1 - Schubert, Nils A1 - Günster, Jens A1 - Stawarczyk, B. A1 - Zocca, Andrea T1 - Additive manufacturing of glass-ceramic dental restorations by layerwise slurry deposition (LSD-print) N2 - This study is dedicated to the additive manufacturing of a feldspar glass-ceramic for dental applications by LSD-print (layerwise slurry deposition) technology, a variation of binder jetting using water-based ceramic slurries as feedstock. This technology was investigated for the manufacturing of single tooth restoration demonstrators with good aesthetic properties, and to compare the additively manufactured material with a commercial reference. Model restorations with > 99 % relative density were processed with a debinding and firing cycle of 45 min, however the whole process chain accounts for up to 30 hours. Significant differences between LSD-printed and reference materials were found for fracture strength, fracture toughness and Martens parameters. Printing orientation affected shrinkage and fracture strength, but not fracture toughness and Martens parameters. Nevertheless, the results suggest that the LSD-print technology processing the developed slurry is a promising option for manufacturing dental restorations meeting class 1a requirements according to DIN EN ISO 6871:2019–01. KW - Additive Manufacturing KW - 3D-printing KW - LSD-print KW - Dental ceramics KW - Glass-ceramic KW - Debinding KW - Firing KW - Sinter-crystallization PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624768 DO - https://doi.org/10.1016/j.jeurceramsoc.2025.117235 VL - 45 IS - 7 SP - 1 EP - 13 PB - Elsevier Ltd. AN - OPUS4-62476 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bäßler, Ralph A1 - Bettge, Dirk A1 - Bender, R. A1 - Féron, D. A1 - Mills, D. A1 - Ritter, S. A1 - de Graeve, I. A1 - Dugstad, A. A1 - Grassini, S. A1 - Hack, T. A1 - Halama, M. A1 - Han, E.-H. A1 - Harder, T. A1 - Hinds, G. A1 - Kittel, J. A1 - Krieg, R. A1 - Leygraf, C. A1 - Martinelli, L. A1 - Mol, A. A1 - Neff, D. A1 - Nilsson, J.-O. A1 - Odnevall, I. A1 - Paterson, S. A1 - Paul, S. A1 - Prosek, T. A1 - Raupach, M. A1 - Revilla, R. I. A1 - Ropital, F. A1 - Schweigart, H. A1 - Szala, E. A1 - Therryn, H. A1 - Tidblad, J. A1 - Virtanen, S. A1 - Volovitch, P. A1 - Watkinson, D. A1 - Wilms, M. A1 - Winning, G. A1 - Zheludkevich, M. T1 - La corrosion: un défi pour une société durable N2 - Une transition mondiale vers des systèmes énergétiques plus durables, abordables et fiables a été initiée par l’accord de Paris et l’Agenda 2030 des Nations unies pour un développement durable. Il s’agit là d’un défi industriel majeur car les systèmes et infrastructures énergétiques résilients au changement climatique exigent de se positionner pour le long terme. Se pencher sur le comportement dans la durée des matériaux structurels - principalement des métaux et des alliages - s’impose alors comme une nécessité. Dans cette optique, « La corrosion : un défi pour une société durable »présente une série de cas montrant l’importance de la tenue à la corrosion et de la protection anticorrosion des métaux et des alliages pour le développement de systèmes durables, économiques et fiables de production d’énergie. KW - Corrosion KW - Coûts de la corrosion KW - Protection KW - Anticorrosion KW - Stratégies deprévention PY - 2023 DO - https://doi.org/10.51257/a-v1-cor2000 SN - 2555-5383 VL - 2023 IS - Avril SP - 1 EP - 23 CY - Saint-Denis, France AN - OPUS4-57927 LA - fra AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Karl, D. A1 - Duminy, T. A1 - Lima, P. A1 - Kamutzki, F. A1 - Gili, A. A1 - Zocca, Andrea A1 - Günster, Jens A1 - Gurlo, A. T1 - Clay in situ resource utilization with Mars global simulant slurries for additive manufacturing and traditional shaping of unfired green bodies N2 - The wet processing of regolith simulant for clay in situ resource utilization (ISRU) on Mars is presented. The two raw materials from the Mars global simulant family, one without clay (MGS-1) and one with clay - sodium montmorillonite smectite - (MGS-1C) were milled and mixed to produce a simulant with small particle size and reduced clay content (MGS-1C/8). All three simulants and the pure clay raw material were extensively characterized using XRF, synchrotron XRD, gas adsorption and gas pycnometry methods. In a straightforward processing approach, MGS-1C/8 was mixed with water and different dispersant approaches were investigated, all of which gave stable slurries. Particle size distribution, rheology, ion concentration, pH and electrical conductivity of these slurries were characterized. The slurry systems can easily be adapted to fit all typical ceramic shaping routes and here parts of varying complexity from slip casting, throwing on a potter's wheel and additive manufacturing, including material extrusion (robocasting) and binder jetting (powder bed 3D printing) were produced. The unique properties of the sodium montmorillonite clay, which is readily accessible in conjunction with magnesium sulfate on the Martian surface, acted as a natural nanosized binder and produced high strength green bodies (unfired ceramic body) with compressive strength from 3.3 to 7.5 MPa. The most elaborate additive manufacturing technique layerwise slurry deposition (LSD) produced water-resistant green bodies with a compressive strength of 30.8 ± 2.5 MPa by employing a polymeric binder, which is similar or higher than the strength of standard concrete. The unfired green bodies show sufficient strength to be used for remote Habitat building on Mars using additive manufacturing without humans being present. KW - Mars KW - Smectite KW - Clay ISRU KW - MGS-1 regolith simulant KW - 3D printing KW - Additive manufacturing PY - 2020 DO - https://doi.org/10.1016/j.actaastro.2020.04.064 VL - 174 SP - 241 EP - 253 PB - Elsevier Ltd. AN - OPUS4-50870 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Günster, Jens T1 - Research and carrier in governmental research institute in Japan and Germany N2 - Being invited to Japan in 1996 as a Humboldt/STA was on of the most exciting things in my life. Not that it is on an absolute scale the most exciting thing still, but at that time, just after finalizing my PhD and thinking what is coming next, it was. KW - Networking PY - 2022 DO - https://doi.org/10.11470/oubutsu.91.2_115 SN - 0369-8009 VL - 91 IS - 2 SP - 115 EP - 117 PB - Gakkai CY - Tōkyō AN - OPUS4-54462 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bäßler, Ralph T1 - Study of Polyaniline/Silicon Dioxide based Coating on Carbon Steel in Artificial Geothermal Brine N2 - By using the available resources in Indonesia, such as silicon dioxide and marine coating base, the PANI/SiO2 modified alkyd coating was able to protect carbon steel in a deaerated artificial geothermal water. The screening of coatings shows that the modification by adding individual pigment was not sufficient to protect carbon steel even during a short-term exposure, indicated by the discoloration after only seven days of exposure. Electrochemical tests indicated that there was no significant change in the Ecorr between the coated and uncoated carbon steel at room temperature. At 150 °C, the coated carbon steel has a lower potential than that of carbon steel, indicating that the coating is protecting carbon steel cathodically or slowing down the corrosion reaction. Finally, a long-term exposure test confirmed that the PANI/SiO2 modified coating successfully protects the carbon steel in the Sibayak artificial geothermal water up to 150 °C for 6 months. T2 - World Geothermal Congress CY - Online meeting DA - 15.06.2021 KW - Coatings KW - Corrosion KW - Polyaniline KW - Sibayak KW - SiO2 KW - Geothermal PY - 2021 AN - OPUS4-52831 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Zocca, Andrea T1 - Continuous layer deposition for the Additive Manufacturing of ceramics by Layerwise Slurry Deposition (LSD-print) N2 - Powder bed technologies are amongst the most successful Additive Manufacturing (AM) techniques. The application of these techniques to most ceramics has been difficult so far, because of the challenges related to the deposition of homogeneous powder layers when using fine powders. In this context, the "layerwise slurry deposition" (LSD) has been developed as a layer deposition method enabling the use of powder bed AM technologies also for advanced ceramic materials. The layerwise slurry deposition consists of the layer-by-layer deposition of a ceramic slurry by means of a doctor blade, in which the slurry is deposited and dried to achieve a highly packed powder. Not only very fine, submicron powders can be processed with low organics, but also the dense powder bed provides excellent support to the parts built. The LSD technology can be combined with binder jetting to develop the so-called “LSD-print” process. LSD-print combines the high-speed printing of binder jetting with the possibility of producing a variety of high-quality ceramics with properties comparable to traditional processing. The latest development of this technology shows that it is possible to print ceramic parts in a continuous process by depositing a layer onto a rotating platform, growing a powder bed following a spiral motion. The unique mechanical stability of the layers in LSD-print allows to grow a powder bed several centimeters thick without any lateral support. The continuous layer deposition allows to achieve a productivity more than 10X higher compared to the linear deposition, approaching a build volume of 1 liter/hour. T2 - 3rd Global Conference and Exhibition on Smart Additive Manufacturing, Design & Evaluation Smart MADE CY - Osaka, Japan DA - 10.04.2024 KW - Additive Manufacturing KW - Ceramic KW - Layerwise slurry deposition KW - LSD-print KW - Slurry KW - Binder jetting PY - 2024 AN - OPUS4-60055 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 - Two-Photon-Polymerization for Ceramics Powder Processing 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 laser 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) for the additive manufacture of filigree structures within the volume of ceramic slurries. T2 - DKG Jahrestagung 2023 CY - Jena, Germany DA - 27.03.2023 KW - Additive Manufacturing KW - Transparent ceramics PY - 2023 AN - OPUS4-59880 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Meyer, Lena T1 - 3-D Druck in Schwerelosigkeit – Patentanmeldung für den Bau für Werkzeug und Ersatzteilen im Weltall N2 - Präsentation der Aktivitäten an der BAM im Bereich 3-D Druck in Schwerelosigkeit. T2 - Besuch des Deutschen Patent- und Markenamtes DPMA München CY - Berlin, Germany DA - 19.07.2022 KW - Additive manufacturing KW - Microgravity KW - Patent KW - Powder KW - Additive Fertigung KW - 3D Druck KW - Schwerelosigkeit PY - 2022 AN - OPUS4-56314 LA - mul AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Günster, Jens T1 - Continuous layer deposition for the Additive Manufacturing of ceramics by Layerwise Slurry Deposition N2 - Powder bed technologies are among the most successful additive manufacturing (AM) techniques. The application of these techniques to most ceramics has been difficult due to the challenges associated with the deposition of homogeneous powder layers when using fine powders. In this context, layerwise slurry deposition (LSD) has been developed as a deposition method that enables the use of powder bed AM technologies for advanced ceramic materials. In layerwise slurry deposition, a ceramic slurry is deposited in layers using a doctor blade and dried to produce a highly compacted powder. Not only can very fine submicron powders with low organic content be processed, but the dense powder bed also provides excellent support for the manufactured parts. The latest development of this technology shows that it is possible to print ceramic parts in a continuous process by depositing a layer on a rotating platform on which a powder bed grows in a spiral motion. The unique mechanical stability of the layers in LSD printing makes it possible to build up a powder bed several centimeters thick without lateral support. Continuous layer deposition achieves more than 10 times the productivity of linear deposition, approaching a build volume of 1 liter per hour. T2 - International Conference on Additive Manufacturing Technology Frontiers CY - Xi’an, China DA - 11.04.2025 KW - Ceramic KW - advanced ceramics PY - 2025 AN - OPUS4-63963 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Waske, Anja T1 - A unique authenticator for additively manufactured parts derived from their microstructure N2 - In the field of additive manufacturing, the ability to uniquely identify and authenticate parts is crucial for certification, logistics, and anti-counterfeiting efforts. This study introduces a novel methodology that leverages the intrinsic microstructural features of additively manufactured components for their identification, authentication, and traceability. Unlike traditional tagging methods, such as embedding QR codes on the surface [1] or within the volume of parts, this approach requires no alteration to the printing process, as it utilizes naturally occurring microstructural characteristics. The proposed workflow [2] involves the analysis of 3D micro-computed tomography data to identify specific voids that meet predefined identification criteria. This method is demonstrated on a batch of 20 parts manufactured with identical process parameters, proving capable of achieving unambiguous identification and authentication. By establishing a tamper-proof link between the physical part and its digital counterpart, this methodology effectively bridges the physical and digital realms. This not only enhances the traceability of additively manufactured parts but also provides a robust tool for integrating digital materials, parts databases, and product passports with their physical counterparts. T2 - Artificial Intelligence in MSE CY - Bochum, Germany DA - 18.11.2025 KW - Authentication KW - Additive Manufacturing KW - Non-destructive testing PY - 2025 AN - OPUS4-65204 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Baesso, Ilaria A1 - Karl, D. A1 - Spitzer, Andrea A1 - Gurlo, A. A1 - Günster, Jens A1 - Zocca, Andrea T1 - Characterization of powder flow behavior for additive manufacturing N2 - The flow behavior of powders has an essential role in many industrial processes, including powder bed additive manufacturing. The characterization of the flow behavior is challenging, as different methods are available, and their suitability for an application in additive manufacturing is still controversial. In this study, six standardized methods (measurement of bulk density by ISO 60 and by ASTM B329, angle of repose by ISO 4324, discharge time by ISO 6186 and by ASTM B964-16, and Hausner Ratio by ASTM 7481 – 18), the rotating drum method (by GranuDrum) and powder rheometry (Anton Paar powder cell), were applied to five size fractions of a crushed quartz sand powder and compared. A statistical approach is proposed and discussed to correlate the obtained flowability indexes with the packing density of powder beds deposited layer-by-layer, and these correlations are compared between methods. Overall, the measurement of bulk density by ASTM B329 that showed the best correlation with the powder bed density. Advanced methods such as the rotating drum method and powder rheometry did not demonstrate particularly good correlations, however they provided complementary information which can be useful to assess the dynamic behavior of powders. KW - Powder flow KW - Flowability KW - Powder bed additive manufacturing KW - Powder rheology PY - 2021 DO - https://doi.org/10.1016/j.addma.2021.102250 SN - 2214-8604 VL - 47 SP - 1 EP - 14 PB - Elsevier CY - Amsterdam AN - OPUS4-53229 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rashidi, Reza A1 - Vaerst, Olivia A1 - Riechers, Birte A1 - Rösner, Harald A1 - Wilde, Gerhard A1 - Maaß, Robert T1 - Atomic-scale strain fluctuations as an origin for elastic microstructures in metallic glasses N2 - Metallic glasses (MGs) exhibit an elastic microstructure that spans from a few to hundreds of nanometers, the origin of which continues to remain poorly understood. Here we employ four-dimensional scanning transmission electron microscopy (4D-STEM) on a Zr65Cu25Al10 (at. %) bulk MG. Mapping local diffraction patterns over representative areas also probed elastically with automated nanoindentation, two comparable correlation length scales have been identified. Specifically, local diffraction patterns are analyzed with respect to their ellipticity, revealing systematic fluctuations between positive and negative volumetric strains. A power spectrum analysis of the strain fluctuations returns a dominant length scale of the order of 100 nm, which is very much compatible with what elastic property mapping indicates. Annealing reduces the magnitude of the statistical strain fluctuations, without strongly affecting the associated fluctuation length scale. These findings demonstrate that atomic-scale strains are very likely the origin of the structurally unexpected large elastic fluctuations obtained in nanoscale contact mechanics experiments. KW - Metallic glass KW - 4D-STEM KW - Strain anisotropy KW - Nanoindentation KW - Elastic microstructure KW - Heterogeneities PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654991 DO - https://doi.org/10.1016/j.actamat.2026.121982 SN - 1359-6454 VL - 308 SP - 1 EP - 8 PB - Elsevier Inc. AN - OPUS4-65499 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Le, Quynh Hoa A1 - Bäßler, Ralph A1 - Bettge, Dirk T1 - Electrochemical behaviors of casing steel/mortar interface in CO2 saturated aquifer fluid N2 - To reveal the corrosion resistance of casing steel/mortar interface in CO2 injection condition, sandwich samples were prepared and exposed up to 20 weeks in aquifer fluid under 10 MPa and 60 °C. Cross section analysis revealed the crevice corrosion as main mechanism instead of pitting corrosion, which would be expected to happen in the extremely high Chloride concentration. Detailed analysis using EDS line scan shown the slow diffusion of Chloride, suggesting why pitting did not happen after 20 weeks. To mimic the passivated steel surface, the steel coupon was passivated in simulated pore solution having pH 13.5 for 42 days. The passivated coupon was further exposed to NGB solution for 28 days. Electrochemical characterization was performed along the exposure processes to reveal the change in impedance, indicating the corrosion resistance of steel casing/mortar interface. T2 - EUROCORR 2022 CY - Berlin, Germany DA - 28.08.2022 KW - Corrosion KW - CO2 quality KW - Pipeline network KW - CCS PY - 2022 SP - 859 EP - 865 PB - European Federation of Corrosion AN - OPUS4-55622 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zocca, Andrea A1 - Müller, Bernd R. A1 - Laquai, René A1 - Kupsch, Andreas A1 - Wieder, Frank A1 - Benemann, Sigrid A1 - Wilbig, Janka A1 - Günster, Jens A1 - Bruno, Giovanni T1 - Microstructural characterization of AP40 apatite-wollastonite glass-ceramic N2 - The microstructure of an apatite-wollastonite (code name AP40) glass-ceramic is analyzed in this study by combining 2D microscopy, phase analysis, X-ray absorption and synchrotron X-ray refraction computed tomography (XCT and SXRCT, respectively). It is shown that this combination provides a useful toolbox to characterize the global microstructure in a wide scale range, from sub-micrometer to millimeter. The material displays a complex microstructure comprising a glassy matrix with embedded fluorapatite and wollastonite small crystals. In this matrix, large (up to 200 μm) spike-shaped structures are distributed. Such microstructural features are oriented around a central sphere, thereby forming a structure resembling a sea urchin. A unique feature of SXRCT, in contrast to XCT, is that internal interfaces are visualized; this allows one to show the 3D distribution of these urchins with exceptionally good contrast. Furthermore, it is revealed that the spike-shaped structures are not single crystals, but rather composed of sub-micrometric crystals, which are identified as fluorapatite and diopside phases by SEM-EDX analysis. KW - Glass-ceramic KW - X-ray refraction KW - Computed tomography KW - Microstructure PY - 2023 DO - https://doi.org/10.1016/j.ceramint.2022.12.130 SN - 0272-8842 VL - 49 IS - 8 SP - 12672 EP - 12679 PB - Elsevier Science CY - Amsterdam AN - OPUS4-57452 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Meyer, Lena T1 - Laser beam melting additive manufacturing at μ-gravity N2 - In-space manufacturing (ISM) provides the opportunity to manufacture and repair critical components on future human spaceflight missions. For explorations to Mars and beyond, ISM is a key strategy not only due to the long travel distances and high costs of supply from earth but also to be able to safely work in space for years. Human spaceflight is still dependent on shipments from earth that can fail for several reasons. ISM is a valuable alternative to ensure the timely and safe resupply of space missions. With additive manufacturing (AM) technologies, components are built directly from a 3D computer-aided-design (CAD) model which offers the advantages of freedom of design and the production of complex and ready-to-use parts. A virtual tool box with 3D models in space or the supply of information instead of components from earth to space can strongly benefit future missions. For industrial use, most research has focused on laser based additive manufacturing processes such as laser beam melting (LBM) where metallic powder particles are spread into a uniform powder bed and melted by a laser to the desired shape. In the absence of gravity, the handling of metal powders, which is essential for the process, is challenging. We present an evolution of an AM system, where a gas flow throughout the powder bed is applied to stabilize the powder bed. This is needed to compensate for the missing gravitational forces in microgravity experiments on parabolic flight campaigns. The system consists of a porous building platform acting as a filter for the fixation of metal particles in a gas flow. It is driven by reduced pressure established by a vacuum pump underneath the platform. The system creates a drag force that directs the particles towards the porous building platform, similar to the effect of the gravitational force. The AM system with its gas-flow-assisted powder deposition has been tested in several parabolic flight campaigns, and stainless-steel powder has successfully been processed during microgravity conditions. Different powder recoating mechanisms have been investigated to assess the homogeneous distribution of the powder as well as the attachment of the next layer to the powder bed. These mechanisms included different container designs with parallel double blades and with a V-shape at the bottom, and a roller recoating system. The samples presented are the first metal parts ever manufactured using LBM in μ-gravity. In addition to manufacturing in a μ-gravity environment, the experiments have shown the feasibility to manufacture components at different accelerations during the parabolic flight: hyper gravity (1.8 g), μ-gravity (< 0.01 g) and 1 g. Recent results will also be presented describing the application of this LBM setup in a parabolic flight campaign with mixed lunar, martian and µ-gravity acceleration, during which the processing of a lunar regolith simulant powder was tested. For ISM, the development and testing of the proposed AM system demonstrates that LBM can be considered a viable technology for the manufacturing of metal and ceramic parts in a μ-gravity or reduced-gravity environment. T2 - International Conference on Advanced Manufacturing CY - Online meeting DA - 07.03.2022 KW - μ-gravity KW - In-space manufacturing KW - Additive manufacturing KW - Laser beam melting KW - Microgravity KW - Stainless steel KW - Lunar regolith simulant PY - 2022 AN - OPUS4-54450 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Meyer, Lena T1 - Powder based Additive Manufacturing in Space N2 - Abstract of the event: 'The area of New Space is a vastly growing and dynamic field with a high innovative potential and many exciting ideas. After decades where activities in space were dominated and funded mainly by governmental agencies, a new industry is forming and new business models are being developed around ideas like satellite-based internet, space travel, space mining, geo-monitoring etc. For space applications, lightweight design is crucial to keep the costs at a minimum. This Innovation Day will introduce the field of New Space and present the variety of exciting opportunities that arise for composites based on their excellent lightweight potential.' Another research area is now arising in the field of 3D printing or additive manufacturing of fiber composite materials in space. At the event, we presented on the opportunities and our experiences of using a powder based additive manufacturing process for in-space manufacturing applications. T2 - CU Innovation Day - New opportunities and applications in space with composites CY - Online meeting DA - 29.03.2022 KW - μ-gravity KW - In-space manufacturing KW - Additive manufacturing KW - Microgravity KW - Powder PY - 2022 AN - OPUS4-54559 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lanzino, Maria Carolina A1 - Le, Long-Quan R. V. A1 - Wilbig, Janka A1 - Rheinheimer, Wolfgang A1 - Seidenstuecker, Michael A1 - Günster, Jens A1 - Killinger, Andreas T1 - Thin GB14 coatings on implants using HVSFS N2 - Enhancing osseointegration, the process by which medical implants securely bond to bone, is crucial for improving patient outcomes in orthopedics and dental surgery. Calcium alkali orthophosphates, with their superior bioactivity, resorbability, and chemical resemblance to bone minerals, have emerged as promising candidates for implant coatings. These materials offer improved solubility and lower melting points due to the substitution of calcium with potassium and sodium, along with the addition of magnesium oxide. This study investigates GB14 calcium alkali orthophosphate coatings applied via High Velocity Suspension Flame Spraying (HVSFS), a technique that enables precise control over coating properties. A porosity target of &gt;10% was set to promote bone growth, and we achieved porosities up to 13%, ensuring better cell penetration and stability at the implant-bone interface. Coatings were produced using different gas parameters and distances, with their microstructure and phase composition analyzed using scanning electron microscope (SEM), Vickers hardness testing and X-ray diffraction (XRD). Additionally, roughness and porosity were also assessed. Different coating’s microstructures were achieved by varying stand-off distance and gas parameters. Increasing stand-off distance while reducing gas stoichiometry enabled the production of calcium alkali orthophosphate coatings with fewer cracks, higher porosity and a hardness level comparable to that of state-of-the-art tricalcium phosphate (TCP) coatings. The sample with optimized properties in terms of achieved microstructure and topography was selected for in vitro testing using MG63 osteosarcoma cells to evaluate cell proliferation and adhesion. WST (I) assay, LDH assay, and live/dead staining confirmed the biocompatibility of the coatings, highlighting the potential of HVSFS to enhance osseointegration and outperform conventional methods in implantology. No relevant cytotoxicity could be shown and cells show a good proliferation over time. These results highlight thus the potential of HVSFS to produce thin, bioactive and resorbable coatings to enhance osseointegration. KW - Bio ceramics KW - Spray coating PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-623983 DO - https://doi.org/10.3389/fmats.2024.1522447 SN - 2296-8016 VL - 11 IS - 1522447 SP - 1 EP - 14 PB - Frontiers Media SA AN - OPUS4-62398 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller-Elmau, Johanna T1 - 2PP of ceramic – What’s next? N2 - Photon-based additive manufacturing technologies such as SLA, DLP, LCM, moreover volumetric two-photon-polymerization (2PP), Xolography and holographic technologies promise the highest accuracy and dimensional freedom. To transfer the light through the feedstock it needs sufficient transparency. Ceramic particles used for powder processing routes act as scattering sites and therefore hinder the light transmission, unless… The particle size and particle size distribution are chosen small and narrow enough. Particles smaller than roughly 1/10th of the light wavelength, mostly nanoparticles around 5nm size, decrease scattering vastly. This turns resins even with homogeneously distributed ceramic weight fraction of up to 80% transparent again. Feedstocks were prepared for the highly accurate two-photon-polymerization gaining the smallest yttria stabilized zirconia structures with a resolution of 500nm and unique mechanical properties. The same feedstock was applied to DLP and LCM as layer-by-layer AM-technologies for bigger parts. Hybridizing both technologies enables ceramic parts with microscopic accuracy at macroscopic dimensions. The feedstock was even applied to the volumetric Xolography with the highest transparency requirement so far and to versatile and flexible holographic AM. What are the next steps? Can those proof-of -concept studies be transferred to industrial applications and what are the hurdles on the way? How to make the stretch between fundamental research and application-oriented development? T2 - ECERS CY - Dresden, Germany DA - 31.08.2025 KW - Tranparent KW - Ceramic KW - Two-photon-polymerization PY - 2025 AN - OPUS4-64939 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sänger, Johanna Christiane A1 - Schwentenwein, Martin A1 - Bermejo, Raúl A1 - Günster, Jens T1 - Hybridizing Lithography-Based Ceramic Additive Manufacturing with Two-Photon-Polymerization N2 - Stereolithography processes such as lithography-based ceramic manufacturing (LCM) are technologies that can produce centimeter-sized structures in a reasonable time frame. However, for some parts specifications, they lack resolution. Two-photon-polymerization (2PP) ensures the highest geometric accuracy in additive manufacturing so far. Nevertheless, building up parts in sizes as large as a few millimeters or even centimeters is a time-consuming process, which makes the production of 2PP printed parts very costly. Regarding feedstock specification, the requirements for 2PP are different to those for LCM, and generally, feedstocks are designed to meet requirements for only one of these manufacturing technologies. In an attempt to fabricate highly precise ceramic components of a rather large size, it is necessary to develop a feedstock that suits both light-based technologies, taking advantage of LCM’s higher productivity and 2PP’s accuracy. Hybridization should bring the desired precision to the region of interest on reasonably large parts without escalating printing time and costs. In this study, specimens gained from a transparent feedstock with yttria stabilized zirconia (YSZ) particles of 5 nm at 70 wt% were presented. The resin was originally designed to suit 2PP, while being also printable with LCM. This work demonstrates how hybrid parts can be sintered into full YSZ ceramics. KW - Additive Manufacturing KW - Transparent ceramic KW - Nano-powder PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-584541 DO - https://doi.org/10.3390/app13063974 SN - 2076-3417 VL - 13 IS - 6 SP - 1 EP - 9 PB - MDPI CY - Basel AN - OPUS4-58454 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Chinellato, Fabio A1 - Wilbig, Janka A1 - Al-Sabbagh, Dominik A1 - Colombo, P. A1 - Günster, Jens T1 - Gas flow assisted powder deposition for enhanced flowability of fine powders: 3D printing of alpha-tricalcium phosphate N2 - The possibility of creating patient-specific individual implants makes Additive Manufacturing technologies of special interest for the medical sector. For substitution of bone defects, powder based Additive Manufacturing by Binder Jetting is a suitable method to produce complex scaffold-like structures made of bioceramics with easily adapted geometries and controlled porosity. The process inherent residual porosity in the printed part, even though desired as it supports bone ingrowth, also leads to limited mechanical strength. Currently, bioceramic scaffolds made by Binder Jetting feature suitable biocompatible and biodegradable properties, while a sufficient mechanical stability is rather challenging. The purpose of this work is to apply the gas flow assisted powder deposition introduced in 2014 by Zocca et al., to the powder bed during printing of bioceramic tablets and scaffolds using α-TCP powder as feedstock. This enables exploiting the advantages of an increased powder bed density, thereby improving the mechanical properties of the printed parts. KW - Additive Manufacturing KW - Binder Jetting KW - Gas flow assisted powder deposition KW - Alpha-tricalcium phosphate KW - Scaffold PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510138 DO - https://doi.org/10.1016/j.oceram.2020.100003 SN - 2666-5395 VL - 1 SP - 100003 PB - Elsevier Ltd. AN - OPUS4-51013 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bäßler, Ralph T1 - Preliminary Study on Al2O3 Sol-Gel Coating for Corrosion Protection of Martensitic Stainless Steel in Artificial Geothermal Water N2 - Al2O3 coatings are often used as protective layers on steels against electrochemical and high-temperature corrosion because they are chemically inert and stable at elevated temperatures. This study presents preliminary work on the possibilities of using Al2O3 sol-gel coatings for corrosion protection of martensitic stainless steels in geothermal environments. Al2O3 sol-gel coatings were applied on UNS S42000, which is known to be susceptible to uniform and localized corrosion. The coated steel specimens were then tested in two types of artificial geothermal water, which simulate the geothermal fluids found in Sibayak (SBY), Indonesia, and North German Basin (NGB), Germany, respectively. SBY has pH 4 and 1.5 g/L of chloride ions, whereas NGB has a pH of 6 and 166 g/L of chloride ions. All experiments were carried out in autoclaves at 150 °C and 1 MPa under the deaerated condition. Evaluations were performed by investigating the surface profiles of both uncoated and coated steels before and after the corrosion test using a Laser Scanning Microscope (LSM) and Scanning Electron Microscope (SEM). Finally, Electrochemical Impedance Spectroscopy (EIS) was performed to compare the corrosion resistance of Al2O3 coated steels in SBY and NGB solutions. It was observed from the corrosion test that Al2O3 coatings are more suitable for use in the geothermal water with a higher pH. T2 - AMPP Annual International Corrosion Conference 2021 CY - Online Meeting DA - 19.04.2021 KW - Protective coating KW - Sol-gel coating KW - Geothermal KW - Martensitic steel KW - Corrosion PY - 2021 AN - OPUS4-52500 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rütters, H. A1 - Fischer, S. A1 - Le, Quynh Hoa A1 - Bettge, Dirk A1 - Bäßler, Ralph A1 - Maßmann, J. A1 - Ostertag-Henning, C. A1 - Lennard Wolf, J. A1 - Pumpa, M. A1 - Lubenau, U. A1 - Knauer, S. A1 - Jaeger, P. A1 - Neumann, A. A1 - Svensson, K. A1 - Pöllmann, H. A1 - Lempp, C. A1 - Menezes, F. A1 - Hagemann, B. T1 - Towards Defining Reasonable Minimum Composition Thresholds – Impacts of Variable CO2 Stream Compositions on Transport, Injection and Storage N2 - The collaborative project “Impacts of impurities in CO2 streams captured from different emitters in a regional cluster on transport, injection and storage (CLUSTER)” aimed to set up recommendations on how to define “reasonable minimum composition thresholds” that CO2 streams should meet when accessing CO2 transport pipeline networks. Within CLUSTER, we investigated potential impacts of CO2 streams with different and temporally variable compositions and mass flow rates along the whole CCS chain. Investigations included, amongst others, impacts on: • corrosion of pipeline steel, • pipeline network design and related transport costs, • alteration of well bore cements, • pressure development and rock integrity, • geochemical reactions, and • petrophysical and geomechanical rock properties. All investigations are based on a generic CCS chain scenario. In this scenario, CO2 streams are captured from a spatial cluster of eleven emitters and collected in a regional pipeline network. Emitters comprise seven fossil fuel-fired power plants equipped with different capture technologies, two cement plants, one refinery and one integrated iron and steel plant. In total, 19.78 Mio t CO2 (including impurities) are captured in the emitter cluster annually. The combined CO2 stream is transported in a trunk line with a length of 400 km (100 km of these offshore) and is injected into five generic storage structures. The storage reservoirs are saline aquifers of the Buntsandstein. The investigations revealed beneficial and deteriorating impacts of different impurities and combinations thereof. Overall, no fundamental technical obstacles for transporting, injecting and storing CO2 streams of the modelled variable compositions and mass flow rates were observed. Based on the results, the CLUSTER project team recommends not to define “minimum composition thresholds” for CO2 streams as strict threshold values for each individual impurity in the stream. Instead, CO2 stream compositions and variabilities for specific CCS projects should be constrained with regard to a set of parameters including i) the overall CO2 content, ii) maximum contents of relevant impurities or elements, iii) acceptable variability of CO2 stream composition, and iv) impurity combinations to be avoided. T2 - The 15th Greenhouse Gas Control Technologies Conference CY - Online meeting DA - 15.03.2021 KW - Corrosion KW - Impurities KW - CO2 quality KW - Pipeline network KW - Whole-chain CCS scenario KW - Recommendations PY - 2021 DO - https://doi.org/10.2139/ssrn.3816427 SP - 1 EP - 18 PB - Elservier AN - OPUS4-52940 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sänger, Johanna C. A1 - Riechers, Birte A1 - Pauw, Brian Richard A1 - Maaß, Robert A1 - Günster, Jens T1 - Microplastic response of 2PP‐printed ceramics N2 - AbstractTwo‐photon polymerization (2PP) additive manufacturing (AM) utilizes feedstocks of ceramic nanoparticles of a few nanometers in diameter, enabling the fabrication of highly accurate technical ceramic design with structural details as small as 500 nm. The performance of these materials is expected to differ from conventional AM ceramics, as nanoparticles and three‐dimensional printing at high resolution introduce new microstructural aspects. This study applies 2PP‐AM of yttria‐stabilized zirconia to investigate the mechanical response behavior under compressive load, probing the influence of smallest structural units induced by the line packing during the printing process, design of sintered microblocks, and sintering temperature and thereby microstructure. We find a dissipative mechanical response enhanced by sintering at lower temperatures than conventional. The pursued 2PP‐AM approach yields a microstructured material with an increased number of grain boundaries that proposedly play a major role in facilitating energy dissipation within the here printed ceramic material. This microplastic response is further triggered by the filigree structures induced by hollow line packing at the order of the critical defect size of ceramics. Together, these unique aspects made accessible by the 2PP‐AM approach contribute to a heterogeneous nano‐ and microstructure, and hint toward opportunities for tailoring the mechanical response in future ceramic applications. KW - Manufacturing KW - Mechanical properties KW - Microstructure KW - Plasticity KW - Zirconia: yttria stabilized PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-605176 DO - https://doi.org/10.1111/jace.19849 SN - 1551-2916 VL - 107 IS - 10 SP - 6636 EP - 6645 PB - Wiley CY - Oxford AN - OPUS4-60517 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ginés-Palomares, Juan-Carlos A1 - Baasch, Julian A1 - Stapperfend, Simon A1 - Facchini, Leonardo A1 - Linke, Stefan A1 - Stoll, Enrico A1 - Günster, Jens T1 - Laser Melting vs. Laser Sintering: Large Area Heat Processing of Lunar South Pole Simulant N2 - A key component of future lunar missions is the concept of In-Situ Resource Utilization (ISRU), which involves the use of local resources to support human missions and reduce dependence on Earth-based supplies. This paper investigates the thermal processing capability of lunar regolith without the addition of binders, with a focus on large-scale applications for the construction of lunar habitats and infrastructure. The study used a simulant of lunar regolith found on the Schrödinger Basin in the South Pole region. This regolith simulant consists of 20 wt% basalt and 80 wt% anorthosite. Experiments were conducted using a high power CO2 laser to sinter and melt the regolith in a 80 mm diameter laser spot to evaluate the effectiveness of direct large area thermal processing. Results indicated that sintering begins at approximately 1,180 °C and reaches full melt at temperatures above 1,360 °C. Sintering experiments with this material revealed the formation of dense samples up to 11 mm thick, while melting experiments successfully produced larger samples by overlapping molten layers and additive manufacturing up to 50 mm thick. The energy efficiency of the sintering and melting processes was compared. The melting process was about 10 times more energy efficient than sintering in terms of material consolidation, demonstrating the promising potential of laser melting technologies of anorthosite-rich regolith for the production of structural elements. KW - Additive Manufacturing KW - Laser melting KW - ISRU KW - Moon KW - Regolith PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639614 DO - https://doi.org/10.1016/j.amf.2025.200226 SN - 2950-4317 VL - 4 IS - 3 SP - 1 EP - 13 PB - Elsevier Ltd. AN - OPUS4-63961 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Brandić Lipińska, M. T1 - PAVER - Contextualizing laser sintering within a lunar technology roadmap N2 - The Global Exploration Strategy of the International Space Exploration Coordination Group (ISECG) describes a timeframe of 2020 and beyond with the ultimate aim to establish a human presence on Mars towards the 2040ies. The next steps lie on the Moon with a focus on the coming 10 years. Early lunar surface missions will establish a capability in support of lunar science and prepare and test mission operations for subsequent human exploration of Mars and long-duration human activities on the Moon. Given the extreme costs involved in the shipping of material from Earth, a prerequisite for future human exploration is the manufacturing of elements directly on the Moon’s surface. Unlike the equipment, which at the beginning will have to be brought from Earth, raw materials and energy could be available following the concept of In-Situ Resource Utilization. The ESA OSIP PAVING THE ROAD (PAVER) study investigates the use of a laser to sinter regolith into paving elements for use as roadways and launch pads thus mitigating dust issues for transport and exploration vehicles. The ESA-funded study examines the potential of using a laser (12 kW CO2 laser with spot beam up to 100 mm) for layer sintering of lunar and martian regolith powders to manufacture larger 3D elements and provide know-how for the automatic manufacture of paving elements in the lunar environment. The project contributes to the first step toward the establishment of a lunar base and will lead to the construction of equipment capable of paving areas and manufacturing 3D structures. PAVER project sets the starting point for an examination of the larger context of lunar exploration. Mission scenarios will look at different phases of lunar exploration: Robotic Lunar Exploration, Survivability, Sustainability, and Operational Phase. A proposed Technology Roadmap investigates the mission scenario and analyses how, and to which extent, laser melting/sintering will play a role in the various phases of exploration. The paper contextualizes laser sintering within selected mission scenarios and discusses the different kinds of infrastructure that can be produced at each phase of the mission. The outcome of the study includes the detailing of the TRL steps in the project and an outline of a timeline for the different elements. Covered aspects include terrain modelling such as operation pads, roadways, or towers, non-pressurized building structures to protect machinery, and habitat envelopes, to protect and shield humans against dust, micrometeoroids, and radiation. T2 - 73rd International Astronautical Congress (IAC) CY - Paris, France DA - 18.09.2022 KW - Additive manufacturing KW - ISRU KW - Infrastructure KW - Lunar habitat KW - Paving KW - Solar sintering PY - 2022 AN - OPUS4-56529 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Zocca, Andrea T1 - Additive Manufacturing for dental restorations by layerwise slurry deposition (LSD-print) technology N2 - The growing market of custom-made dental restorations offers a major potential for an application of ceramic additive manufacturing (AM). The possibility to individualize patient specific design and to establish new efficient workflows, from model generation to manufacturing, can be fully exploited by AM technologies. However, for mass customization to be truly envisioned, ceramic AM needs to achieve a level of maturity, aesthetic quality, and productivity comparable to established manufacturing processes. In this presentation, the potential of the “layerwise slurry deposition” LSD-print technology for dental applications will be explored. It has been shown in the past years that the LSD-print can be applied to advanced ceramic materials such as alumina and silicon-infiltrated silicon carbide. For these materials, the LSD-print technology combines the high-speed printing of binder jetting with the possibility of producing a variety of high-quality ceramics. The current development deals with the challenges of applying this technology to a feldspar dental material, comparing the quality of AM restorations with the equivalent material for an established CAD/CAM workflow. Preliminary results not only indicate that the AM material produced by LSD-print can be competitive in terms of mechanical properties, but also that aesthetically satisfactory restorations can be manufactured for veneers, inlays and onlays as well as single unit fixed dental prostheses (FDPs). The presentation focuses on the material and technological challenges alongside the process chain, from the printing process, to debinding, firing and finishing the restorations. T2 - XVIIIth Conference of the European Ceramic Society CY - Lyon, France DA - 02.07.2023 KW - Additive Manufacturing KW - Layerwise slurry deposition KW - dental KW - ceramic PY - 2023 AN - OPUS4-58469 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 - Cornelio, Andrea T1 - NASICON Electrolytes for Room-Temperature Sodium-Sulfur Batteries: from Material Synthesis to Cell Testing N2 - Solid electrolytes (SE) allow to employ alkali-metal negative electrodes (NE) in new cell concepts, increasing energy density and safety of batteries for stationary and portable applications. The aim of this research is to develop a novel NASICON (NA Super Ionic CONductor) electrolyte for room-temperature (RT) sodium-sulfur (Na-S) cells employing a liquid sodium-potassium (Na-K) alloy at the SE/NE interface. The Na-K alloy can improve the interfacial contact between the sodium-metal NE and the SE. T2 - Batterieforum Deutschland 2026 CY - Berlin, Germany DA - 20.01.2026 KW - NASICON KW - Solid Electrolytes KW - Synthesis KW - Characterization KW - Na batteries KW - Electrochemical testing PY - 2026 AN - OPUS4-65423 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - THES A1 - Abel, Andreas T1 - Microstructural and mechanical characterisation of cast Fe-Al-Mo-Ti-B alloys N2 - With the advent of variable renewable energies, long-term energy storage capacities and flexible power generation technologies will be required for reliable grid stability. Hence, power plant technologies and turbomachinery components will continue to be developed and employed for efficient re-conversion of stored energy. With the introduction of new working fluids for higher thermal efficiencies, the working conditions of exposed components and materials will require higher corrosion resistance, but with the same mechanical performance, manufacturability and cost. Intermetallic iron aluminide alloys with their outstanding oxidation and corrosion resistance and good high-temperature properties depict a possible candidate for use in high-temperature structural applications. A quinary Fe-26Al-4Mo-0.5Ti-1B solid-solution alloy with eutectic particle hardening particularly demonstrated competitive mechanical properties compared to high-alloy P92 steels in previous studies. To derive standard material specifications with industrially relevant casting strategies, centrifugal investment-cast Fe-25Al-3.7Mo-0.4Ti-1B was characterised with respect to microstructure, thermophysical properties and mechanical properties under quasi-static tensile and creep loading up to 700 °C. Compared to P92 steel, the alloy demonstrated superior tensile strength above 550 °C and lower creep rates at 650 °C if stresses increase above 170 MPa. At lower temperatures though, the mechanical properties were inferior to P92 steel and related Fe-Al-Mo-Ti-B alloys, which was correlated to large grain sizes, a high tendency to surface and bulk cracking and a pronounced effect of tension-compression asymmetry. In further studies on alloy composition with varying Al, Mo and B concentration, a non-linear relationship of solid-solution hardening with solute Mo concentration was found. In this regard, halving Mo was the most effective measure for reducing brittleness without decreasing strength at room and elevated temperatures. Higher solidification rates and grain refinement down to 30 µm by die casting had a positive effect on ambient tensile strength, but were not achievable by investment casting. Dilatometry and hardness measurements indicated a low thermal vacancy hardening effect which was less sensitive to low-temperature annealing than in B2 FeAl alloys. Although mechanical properties up to 550 °C could be considerably improved by alloy development and processing, ductility at room temperature generally remained below 1%, necessitating substantial design margins for components from Fe-Al-Mo-Ti-B alloys. Despite the inherent limitations of alloy and casting process, the gained insights will help to prioritise future areas of research to mature cost-effective higher-order Fe Al alloys for high-temperature structural applications. KW - Hardness KW - Iron aluminide alloy KW - Micro structure KW - Tensile strength KW - Creep strength PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-632810 DO - https://doi.org/10.5445/IR/1000181739 SP - 1 EP - 179 PB - Karlsruher Institut für Technologie (KIT) CY - Karlsruhe AN - OPUS4-63281 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -