TY - JOUR A1 - Darvishi Kamachali, Reza A1 - Wallis, Theophilius A1 - Ikeda, Yuki A1 - Saikia, U. A1 - Ahmadian, A. A1 - Liebscher, C. A1 - Hickel, Tilmann A1 - Maaß, Robert T1 - Giant segregation transition as origin of liquid metal embrittlement in the Fe-Zn system N2 - A giant Zn segregation transition is revealed using CALPHAD-integrated density-based modeling of segregation into Fe grain boundaries (GBs). The results show that above a threshold of only a few atomic percent Zn in the alloy, a substantial amount of up to 60 at.% Zn can segregate to the GB. We found that the amount of segregation abruptly increases with decreasing temperature, while the Zn content in the alloy required for triggering the segregation transition decreases. Direct evidence of the Zn segregation transition is obtained using high-resolution scanning transmission electron microscopy. Base on the model, we trace the origin of the segregation transition back to the low cohesive energy of Zn and a miscibility gap in Fe-Zn GB, arising from the magnetic ordering effect, which is confirmed by ab-initio calculations. We also show that the massive Zn segregation resulting from the segregation transition greatly assists with liquid wetting and reduces the work of separation along the GB. The current predictions suggest that control over Zn segregation, by both alloy design and optimizing the galvanization and welding processes, may offer preventive strategies against liquid metal embrittlement. KW - CALPHAD KW - Microstructure Design KW - Grain boundary engineering KW - Steels KW - Density-based Model KW - Segregation Engineering PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-584292 DO - https://doi.org/10.1016/j.scriptamat.2023.115758 SN - 1359-6462 SN - 1872-8456 VL - 238 SP - 1 EP - 5 PB - Elsevier CY - Amsterdam AN - OPUS4-58429 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - THES A1 - Charmi, Amir T1 - A multiscale numerical framework for the simulation of anistropic material response of additively manufactured stainless steel 316L undergoing large plastic deformation N2 - Additive manufacturing (AM) offers significantly greater freedom of design compared to conventional manufacturing processes since the final parts are built layer by layer. This enables metal AM, also known as metal 3D printing, to be utilized for improving efficiency and functionality, for the production of parts with very complex geometries, and rapid prototyping. However, despite many technological advancements made in recent years, several challenges hinder the mass adoption of metal AM. One of these challenges is mechanical anisotropy which describes the dependency of material properties on the material orientation. Therefore, in this work, stainless steel 316L parts produced by laser-based powder bed fusion are used to isolate and understand the root cause of anisotropy in AM parts. Furthermore, an efficient and accurate multiscale numerical framework is presented for predicting the deformation behavior of actual AM parts on the macroscale undergoing large plastic deformations. Finally, a novel constitutive model for the plastic spin is formulated to capture the influence of the microstructure evolution on the material behavior on the macroscale. KW - Additive Fertigung KW - Austenitischer Stahl KW - Finite-Elemente-Methode KW - Mehrskalenmodell KW - Simulation PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:gbv:wim2-20240207-173356-002 DO - https://doi.org/10.25643/dbt.59550 SP - 1 EP - 163 PB - Bauhaus-Universität Weimar CY - Weimar AN - OPUS4-59511 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bayerlein, Bernd A1 - Schilling, Markus A1 - von Hartrott, Philipp A1 - Waitelonis, Jörg T1 - Semantic integration of diverse data in materials science: Assessing Orowan strengthening N2 - AbstractThis study applies Semantic Web technologies to advance Materials Science and Engineering (MSE) through the integration of diverse datasets. Focusing on a 2000 series age-hardenable aluminum alloy, we correlate mechanical and microstructural properties derived from tensile tests and dark-field transmission electron microscopy across varied aging times. An expandable knowledge graph, constructed using the Tensile Test and Precipitate Geometry Ontologies aligned with the PMD Core Ontology, facilitates this integration. This approach adheres to FAIR principles and enables sophisticated analysis via SPARQL queries, revealing correlations consistent with the Orowan mechanism. The study highlights the potential of semantic data integration in MSE, offering a new approach for data-centric research and enhanced analytical capabilities. KW - Semantic Interoperability KW - Knowledge Graph KW - Orowan Mechanism KW - Aluminum Alloy Aging KW - Ontology KW - Semantic Data Integration PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-599780 DO - https://doi.org/10.1038/s41597-024-03169-4 VL - 11 IS - 1 SP - 1 EP - 12 PB - Springer Science and Business Media LLC AN - OPUS4-59978 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sonntag, Nadja A1 - Piesker, Benjamin A1 - Ávila Calderón, Luis Alexander A1 - Mohr, Gunther A1 - Rehmer, Birgit A1 - Agudo Jácome, Leonardo A1 - Hilgenberg, Kai A1 - Evans, Alexander A1 - Skrotzki, Birgit T1 - Tensile and Low‐Cycle Fatigue Behavior of Laser Powder Bed Fused Inconel 718 at Room and High Temperature N2 - This study investigates the room‐ and high‐temperature (650 °C) tensile and low‐cycle‐fatigue behavior of Inconel 718 produced by laser powder bed fusion (PBF‐LB/M) with a four‐step heat treatment and compares the results to the conventional wrought material. The microstructure after heat treatment is characterized on different length scales. Compared to the wrought variant, the elastic and yield properties are comparable at both test temperatures while tensile strength, ductility, and strain hardening capacity are lower. The fatigue life of the PBF‐LB/M variant at room temperature is slightly lower than that of the wrought material, while at 650 °C, it is vice versa. The cyclic stress response for both material variants is characterized by cyclic softening, which is more pronounced at the higher test temperature. High strain amplitudes (≥0.7%) at room temperature and especially a high testing temperature result in the formation of multiple secondary cracks at the transitions of regions comprising predominantly elongated grain morphology and columns of stacked grains with ripple patterns in the PBF‐LB/M material. This observation and pronounced crack branching and deflection indicate that the cracks are controlled by sharp micromechanical gradients and local crystallite clusters. KW - Additive manufacturing KW - Fatigue damage KW - Heat treatment KW - Inconel 718 KW - Laser powder bed fusion KW - Low-cycle fatigue KW - Tensile strength PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-599316 DO - https://doi.org/10.1002/adem.202302122 SN - 1527-2648 SP - 1 EP - 17 PB - Wiley AN - OPUS4-59931 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - THES A1 - Suárez Ocano, Patricia T1 - Thermodynamic and microstructural stabilities at high temperatures and their effects on mechanical properties in an AlMo0.5NbTa0.5TiZr refractory high entropy superalloy N2 - Today’s industrial demands challenge the research and development sector to make advances in the design and properties of materials that can withstand harsh environments. The AlMo0.5NbTa0.5TiZr refractory high-entropy superalloy (RSA), with a remarkable morphological similarity to the γ/γ' microstructure of Ni-based superalloys and promising high-temperature compressive properties, has been considered as a candidate for structural applications. However, additional properties need to be investigated in order to assess the suitability of this alloy for high temperature applications. Therefore, this work investigates the thermodynamic and microstructural stabilities of the RSA at room temperature and between 900 and 1100 °C, and their influence on the mechanical properties. Although it is possible to improve the mechanical properties at 20 °C by tuning the cooling rate, long-term high temperature exposures lead to phase instabilities that negatively influence the creep behavior. N2 - Die heutigen industriellen Anforderungen erfordern Fortschritte bei Werkstoffdesign und -entwicklung, insbesondere für raue Umgebungen. Die hochentropische Refraktärsuperlegierung (RSA) AlMo0.5NbTa0.5TiZr, die eine bemerkenswerte morphologische Ähnlichkeit mit der γ/γ'-Mikrostruktur von Ni-Basis-Superlegierungen und vielversprechende Hochtemperatur-Druckeigenschaften aufweist, wurde als Kandidat für strukturelle Anwendungen erwägt. Weitere Eigenschaften müssen untersucht werden, um die Eignung dieser Legierung für Hochtemperaturanwendungen zu beurteilen. In dieser Arbeit werden die thermodynamischen und mikrostrukturellen Stabilitäten von RSA bei Raumtemperatur und zwischen 900 und 1100°C sowie deren Einfluss auf die mechanischen Eigenschaften untersucht. Obwohl es möglich ist, die mechanischen Eigenschaften bei 20 °C durch Abstimmung der Abkühlrate zu verbessern, führen langfristige Hochtemperaturexpositionen zu Phaseninstabilitäten, die das Kriechverhalten negativ beeinflussen. KW - Hochentropielegierung KW - Gefüge (Werkstoffkunde) KW - Mikrostruktur KW - Kriechen KW - Thermodynamische Stabilität KW - High entropy alloys KW - Microstructure KW - Creep KW - Thermodynamic stability PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:hbz:294-108415 DO - https://doi.org/10.13154/294-10841 SP - 1 EP - 170 CY - Bochum AN - OPUS4-59929 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Beygi Nasrabadi, Hossein T1 - Digital representation of materials testing data for semantic web analytics: Tensile stress relaxation testing use case N2 - This study aims to represent an approach for transferring the materials testing datasets to the digital schema that meets the prerequisites of the semantic web. As a use case, the tensile stress relaxation testing method was evaluated and the testing datasets for several copper alloys were prepared. The tensile stress relaxation testing ontology (TSRTO) was modeled following the test standard requirements and by utilizing the appropriate upper-level ontologies. Eventually, mapping the testing datasets into the knowledge graph and converting the data-mapped graphs to the machine-readable Resource Description Framework (RDF) schema led to the preparation of the digital version of testing data which can be efficiently queried on the web. T2 - ICMDA 2024: 7th International Conference on Materials Design and Applications CY - Tokyo, Japan  DA - 09.04.2024 KW - Digitalization KW - Tensile stress relaxation KW - Ontology KW - Mechanical testing KW - Semantic web PY - 2024 AN - OPUS4-59979 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Beygi Nasrabadi, Hossein A1 - Skrotzki, Birgit T1 - Ontology-Oriented Modeling of the Vickers Hardness Knowledge Graph N2 - This research deals with the development of the Vickers hardness knowledge graph, mapping the example dataset in them, and exporting the data-mapped knowledge graph as a machine-readable Resource Description Framework (RDF). Modeling the knowledge graph according to the standardized test procedure and using the appropriate upper-level ontologies were taken into consideration to develop the highly standardized, incorporable, and industrial applicable models. Furthermore, the Ontopanel approach was utilized for mapping the real experimental data in the developed knowledge graphs and the resulting RDF files were successfully evaluated through the SPARQL queries. KW - Data Mapping KW - FAIR Data KW - Ontology KW - Knowledge Graph KW - Vickers Hardness PY - 2024 DO - https://doi.org/10.4028/p-k8Gj2L VL - 149 SP - 33 EP - 38 PB - Trans Tech Publications Ltd CY - Switzerland AN - OPUS4-59981 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Günster, Jens T1 - Tailoring powder properties for the light based volumetric additive manufacture of Ceramics N2 - In order to be able to manipulate ceramic powder compacts and ceramic suspensions (slurries) within their volume with light, a minimum transparency of the materials is required. Compared to polymers and metals, ceramic materials are characterized by the fact that they have a wide electronic band gap and therefore a wide optical window of transparency. The optical window generally ranges from less than 0.3 µm to 5 µm wavelength. In order to focus light into the volume of a ceramic powder compact, its light scattering properties must therefore be tailored. In this study, we present the physical background and material development strategies for the application of two-photon polymerization (2PP) and selective volumetric sintering for the additive manufacturing of structures in the volume of ceramic slips and green compacts. T2 - SmartMade 2024 CY - Osaka, Japan DA - 10.04.2024 KW - Additive Manufacturing KW - Two Photon Polymerization KW - Advanced ceramics PY - 2024 AN - OPUS4-59888 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - 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 - Schröder, Jakob T1 - Diffraction and Single-Crystal Elastic Constants of Laser Powder Bed Fused Inconel 718 N2 - In this presentation, the results of the determination of the diffraction and single-crystal elastic constants of laser powder bed fused Inconel 718 are presented. The analysis is based on high-energy synchrotron diffraction experiments performed at the Deutsches Elektronen-Synchrotron. It is shown that the characteristic microstructure of laser powder bed fused Inconel 718 impacts the elastic anisotropy and therefore the diffraction and single-crystal elastic constants. Finally, the consequences on the diffraction-based residual stress determination of laser powder bed fused Inconel 718 are discussed. T2 - AWT-Fachausschuss 13 "Eigenspannungen" CY - Wolfsburg, Germany DA - 19.03.2024 KW - Additive Manufacturing KW - Laser Powder Bed fusion KW - Diffraction KW - In-Situ Testing KW - Diffraction Elastic Constants PY - 2024 AN - OPUS4-59900 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -