TY - CONF A1 - Bhadeliya, Ashok T1 - High temperature fatigue crack growth in nickel-based alloys joined by brazing and additive manufacturing N2 - Nickel-based alloys have been widely used for gas turbine blades owing to their excellent mechanical properties and corrosion resistance at high temperatures. The operating temperatures of modern gas turbines have been increased in pursuit of increased thermal efficiency. Turbine blades are exposed to these high temperatures combined with mechanical stresses, resulting in material damage through creep, fatigue, and other mechanisms. These turbine blades must be regularly inspected and replaced as needed, to prevent the loss of efficiency, breakdown, and catastrophic failure. Repair of the damaged turbine blades is often a more practical and cost-effective option than replacement, as replacement is associated with high costs and loss of material resources. To this end, state-of-the-art repair technologies including different additive manufacturing and brazing processes are considered to ensure efficient repair and optimum properties of repaired components. In any repaired part, materials property-mismatches and/or inner defects may facilitate the crack initiation and propagation and thus reduce the number of load cycles to failure. Therefore, a fundamental understanding of the fatigue crack growth and fracture mechanisms in joining zones is required to enable the prediction of the remaining life of repaired components and to further improve and adapt the repair technologies. Fatigue crack growth experiments have been conducted on SEN (Single Edge Notch) specimens joined via brazing, and pre-sintered Preform (PSP) and multi-materials (casted/printed) specimens layered via additive manufacturing (AM). The experiments were performed at 950 °C and various stress ratios. The crack growth was measured using DCPD (Direct Current Potential Drop) method. The stress intensity factors for joined SEN specimens were calculated using the finite element method and then used to derive the fatigue crack growth curves. Metallographic and fractographic analyses were conducted to get insight into the fracture mechanism. Results show that the experimental technique for fatigue crack growth was successfully adapted and applied for testing joined specimens. Furthermore, the initial tests indicate that the investigated braze filler material provides a lower resistance to crack growth, and bonding defects cause a crack to deviate to the interface of the base material and joining zone. In AM-sandwich specimens, the crack growth rates are significantly reduced when the crack reaches the interface of printed material and casted material. The obtained crack growth data can be used to calibrate a crack growth model, which will further be utilized to predict the remaining life of repaired components. T2 - DGM Arbeitskreis Mechanisches Werkstoffverhalten bei hoher Temperatur im FachausschussWerkstoffverhalten unter mechanischer Beanspruchung CY - Munich, Germany DA - 10.10.2023 KW - Fatigue crack growth KW - Joined nickel-based alloys PY - 2023 AN - OPUS4-60908 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bhadeliya, Ashok T1 - High temperature fatigue crack growth in nickel-based alloys joined by brazing and additive manufacturing N2 - Nickel-based alloys have been widely used for gas turbine blades owing to their excellent mechanical properties and corrosion resistance at high temperatures. The operating temperatures of modern gas turbines have been increased in pursuit of increased thermal efficiency. Turbine blades are exposed to these high temperatures combined with mechanical stresses, resulting in material damage through creep, fatigue, and other mechanisms. These turbine blades must be regularly inspected and replaced as needed, to prevent the loss of efficiency, breakdown, and catastrophic failure. Repair of the damaged turbine blades is often a more practical and cost-effective option than replacement, as replacement is associated with high costs and loss of material resources. To this end, state-of-the-art repair technologies including different additive manufacturing and brazing processes are considered to ensure efficient repair and optimum properties of repaired components. In any repaired part, materials property-mismatches and/or inner defects may facilitate the crack initiation and propagation and thus reduce the number of load cycles to failure. Therefore, a fundamental understanding of the fatigue crack growth and fracture mechanisms in joining zones is required to enable the prediction of the remaining life of repaired components and to further improve and adapt the repair technologies. Fatigue crack growth experiments have been conducted on SEN (Single Edge Notch) specimens joined via brazing, and pre-sintered Preform (PSP) and multi-materials (casted/printed) specimens layered via additive manufacturing (AM). The experiments were performed at 950 °C and various stress ratios. The crack growth was measured using DCPD (Direct Current Potential Drop) method. The stress intensity factors for joined SEN specimens were calculated using the finite element method and then used to derive the fatigue crack growth curves. Metallographic and fractographic analyses were conducted to get insight into the fracture mechanism. Results show that the experimental technique for fatigue crack growth was successfully adapted and applied for testing joined specimens. Furthermore, the initial tests indicate that the investigated braze filler material provides a lower resistance to crack growth, and bonding defects cause a crack to deviate to the interface of the base material and joining zone. In AM-sandwich specimens, the crack growth rates are significantly reduced when the crack reaches the interface of printed material and casted material. The obtained crack growth data can be used to calibrate a crack growth model, which will further be utilized to predict the remaining life of repaired components. T2 - FEMS EUROMAT 2023 CY - Frankfurt a. M., Germany DA - 03.09.2023 KW - Fatigue crack growth KW - Joined nickel-based alloys PY - 2023 AN - OPUS4-58266 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Manzoni, Anna Maria T1 - High temperature oxidation of CrFeNi in synthetic air N2 - The surface corrosion behaviour is a key issue which determines whether the material is applicable at a given atmosphere. Medium-entropy alloy FeCrNi alloy was exposed to synthetic air at 1000°C, 1050°C, and 1100 °C for up to 1000 h using a thermobalance. The oxidation rate was parabolic at 1000 and 1050°C, but breakaway occurred at 1100°C after 5 h of aging time. The whole oxide scales formed under the isothermal oxidation tests spalled off and additional oxidation tests were carried out at 1000 °C and 1050°C for 24 h and up to 100 h at 1000°C in a tubular furnace. The corrosion behaviour of the MEA was analysed by scanning electron microscope, energy-dispersive X-ray spectroscopy, and X-ray diffraction and compared to the behaviour of 316 L. The experimental results showed that under all conditions chromium is the main diffusion element resulting in the formation of a Cr2O3 layer at the MEA surface. Spallation of the layer induces the formation of additional oxidation products under the surface of the (spalled off) chromia layer. T2 - Euromat 2023 CY - Frankfurt a. M., Germany DA - 03.09.2023 KW - Medium entopy alloy KW - Oxidation KW - Scanning electron microscopy KW - Thermogravimetric analysis PY - 2023 AN - OPUS4-58198 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schilling, Markus T1 - Hochwertige, verlässliche und FAIRe Daten erstellen: Von Ontologien und elektronischen Laborbüchern zu Datenmanagement und Wissenstransfer N2 - Das hochaktuelle Thema der Integration und Wiederverwendung von Wissen und Daten aus Herstellung, Bearbeitung und Charakterisierung von Materialien wird im Zuge der digitalen Transformation in der Materialwissenschaft und Werkstofftechnologie in verschiedenen Projekten adressiert. Dabei stehen die Interoperabilität von nach FAIR-Prinzipien erstellten und veröffentlichten Daten und Anwendungen im Vordergrund. Zur Umsetzung eines komplexen Datenmanagements sowie der Digitalisierung im Bereich der Materialwissenschaften etablieren sich Ontologien zunehmend als belastbares Werkzeug. Sie ermöglichen sowohl menschenlesbare als auch maschinenverständliche und -interpretierbare Wissensrepräsentationen durch semantische Konzeptualisierungen. Im Rahmen des Projektes Plattform MaterialDigital (PMD, materialdigital.de) werden Ontologien verschiedener Ebenen entwickelt (verbindende mid-level sowie Domänen-Ontologien). Die PMD-Kernontologie (PMD Core Ontology - PMDco) ist eine Ontologie der mittleren Ebene), die Verbindungen zwischen spezifischeren MSE-Anwendungsontologien und domänenneutralen Konzepten herstellt, die in bereits etablierten Ontologien höherer Ebenen (top-level Ontology) verwendet werden. Sie stellt somit einen umfassenden Satz von durch Konsensbildung in der Gemeinschaft (geteiltes Vokabular) entstanden Bausteinen grundlegender Konzepte aus der Materialwissenschaft und Werkstofftechnik (MSE) dar. Das primäre Ziel des PMDco-Designs ist es, die Interoperabilität zwischen verschiedenen MSE-bezogenen und anderen Ontologien zu ermöglichen. Die PMDco dient als umfassend ausgelegte und erweiterbare semantische Zwischenschicht, die gemeinsame MSE-Konzepte durch semantisches Mapping auf andere Darstellungen vereinheitlicht, was sie zu einem effizienten Werkzeug zur Strukturierung von MSE-Wissen macht. In dieser Präsentation wird die Version 2.0 der PMDco vorgestellt. Weiterhin wird eine auf die PMDco bezogene normenkonforme ontologische Repräsentation zur Speicherung und Weiterverarbeitung von Zugversuchsdaten präsentiert, die in enger Zusammenarbeit mit Standardisierungsgremien erstellt wurde. Dies umfasst den Weg von der Entwicklung einer Ontologie nach Norm, der Konvertierung von Daten aus Standardtests in das interoperable RDF-Format bis hin zur Verbindung von Ontologie und Daten. Letztendlich können die entsprechenden Daten in einem Triple Store abgelegt und abgefragt werden. Auf Basis dieser Zugversuchsontologie wurde im Folgenden unter Verwendung eines elektronischen Laborbuches (electonic lab notebook – ELN) zur Datenaufnahme eine Praktikumsreihe von Universitätsstudierenden digitalisiert. Dadurch wurde eine vollständig digital integrierte Versuchsführung ermöglicht, die auf andere Versuchsreihen und Experimente übertragbar ist und ebenfalls vorgestellt werden soll. Neben einer erleichterten Aufnahme, Analyse und (Wieder-)Verwendbarkeit von Daten wird damit eine Sensibilisierung von Studierenden für Datenstrukturierung sowie semantische Technologien im Sinne der Aus- und Weiterbildung erreicht. T2 - DVM-Tagung Werkstoffprüfung CY - Berlin, Germany DA - 23.11.2023 KW - Ontologie KW - Semantic Web Technologies KW - Plattform MaterialDigital KW - PMDco KW - Zugversuchsontologie KW - Zugversuch KW - Elektronisches Laborbuch (ELN) PY - 2023 AN - OPUS4-59030 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Maaß, Robert T1 - Intermittent cluster dynamics and temporal fractional diffusion in a bulk metallic glass N2 - Inspired by the ability to track atomic-scale dynamics with x-ray photon correlation spectroscopy (XPCS)1 and recent results of long-term atomistic simulations on material transport2, we reveal here an unprecedented spectrum of short- and long-term relaxation dynamics. Tracked along a 300 000 s long isotherm at 0.98Tg, a Zr-based bulk metallic glass exhibits temporal fluctuations that persist throughout the entire isotherm, demonstrating a continuous heterogeneous dynamics at the probed length scale. In concert with microsecond molecular dynamic simulations, we identify intermittent cluster dynamics as the origin for temporal signatures in the corresponding intensity cross-correlations. Despite temporally heterogeneous aging, the Kohlrausch-Williams-Watts functions is well suited to capture the average intermediate relaxation time regime, but at very long time scales an asymptotic power-law better describes the data. This indicates anomalous diffusion and gives overall strong evidence for temporal fractional diffusion in metallic glasses. We discuss these results in terms of the underlying structural fast and slow relaxation modes and their manifestation in the temporal form of the structural decorrelations. T2 - 9th IDMRCS CY - Chiba, Japan DA - 12.08.2023 KW - Metallic glass KW - Transport KW - Structure KW - Dynamics PY - 2023 AN - OPUS4-60696 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Maaß, Robert T1 - Liquid Metal Embrittlement in High-Strength Steels N2 - One contribution of materials science to energy efficiency is the continuous development of novel high-performance structural materials that push the strength-ductility envelope. A prominent example are modern advanced high-strength steels (AHSSs), which have enabled considerable weight reductions in the automotive sector, thereby enabling greenhouse emission reductions. To protect such advanced alloys from property degradation via corrosion, zinc (Zn) coatings are often applied through galvanization. Whilst protective, a Zn-coating comes with problems – the AHSS substrate becomes susceptible for liquid-metal embrittlement (LME) than can be the origin of significant mechanical property degradation when liquified Zn infiltrates into the steel substrate. Being for from understood, we focus here on non-cracked environments to capture the early stages of LME. This approach revealed the nucleation and growth of nano-scale intermetallic phases inside uncracked GBs (Materials Today Advances 13, 100196, 2022), highlighting the complex multi-phase microstructure developing before cracking occurs. To shed further light on the early stages of LME in AHSSs, we also consider the microstructural evolution of interrupted welds. We discuss our findings in the context of the time-resolved substructure evolution right beneath the interface between the AHSS and the Zn-based coating and track how Zn progressively infiltrates the substrate along phase and grain boundaries. The experimental results are further corroborated with thermodynamic simulations. T2 - ASATM CY - Singapore DA - 10.01.2023 KW - Liquid-metal embrittlement KW - Steels KW - Grain boundaries KW - Micro-cracking PY - 2023 AN - OPUS4-60647 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - de Camargo, Andrea Simone Stucchi T1 - Luminescent multifunctional nanostructures for sensing and theranostics applications N2 - The research carried out at the Laboratory of Spectroscopy of Functional Materials at IFSC/USP, in Brazil, is focused on the synthesis and structural-property correlation of luminescent materials including rare-earth (RE) doped glasses, ceramics and hybrid host-guest materials. For the past five years, we have been particularly interested in the development of single- and multifunctional nanosystems based on core-shell upconversion nanoparticles (UCNP) associated with dyes, organometallic complexes and other organic molecules, for biophotonic and sensing applications. In these systems, we take advantage of energy transfer between the UCNPs and the molecules to either supress or enhance luminescent response. Examples include the possibility of bioimaging and photodynamic therapy of bacteria and cancer cells, simultaneous magnetothermia and thermometry, localized O2 sensing, fast detection and quantification of biological markers (e.g. kidney disease) and microorganisms. On what concerns the development of luminescent sensors - a recently started project, our aim is to develop paper-based platforms for point-of-care devices. In this presentation, an overview of our contributions for the past years and our future aims will be presented with several examples. T2 - ICL2023 - 20th International Conference on Luminescence CY - Paris, France DA - 27.08.2023 KW - Upconversion KW - Sensing KW - Theranostics KW - Nanoparticles KW - Photodynamic therapy PY - 2023 AN - OPUS4-60362 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - de Camargo, Andrea Simone Stucchi T1 - Luminescent multifunctional nanostructures for sensing and theranostics applications N2 - An overview of the work carried out at LEMAF - Laboratory of Spectroscopy of Functional Materials at IFSC/USP was given. The work presented focus on the design, production and functional characterization of multifunctional nanoparticles. T2 - NANOANDES - Latin American School on Nanomaterials and Appllications CY - Araraquara, SP, Brazil DA - 10.10.2023 KW - Multifunctional nanoparticles KW - Upconversion nanoparticles KW - Quantum dots KW - Noble metal nanoparticles PY - 2023 AN - OPUS4-60363 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Abel, Andreas A1 - Zapala, P. T1 - Materials Applications FeAl (WAFEAL) N2 - The increasing importance of resource availability and closed-loop material cycles are driving materials research to reduce alloying content in conventional materials or even substitute them with more sustainable alternatives. Intermetallic iron aluminide alloys (FeAl) present a potential alternative. Many alloy concepts for improved high-temperature properties or ductility have already been successfully implemented in casting technologies on a laboratory scale. However, successful testing of FeAl alloys on an industrial scale was still pending at the beginning of the project. Therefore, the aim of the project was to develop simulation-based casting concepts for industrial casting processes using the base alloy Fe-26Al-4Mo-0.5Ti-1B and to narrow down process limits by means of hot cracking tests. Findings were transferred into practice-oriented guidelines for casting of iron aluminides, which is accessible to future applicants in SMEs. The focus was placed on centrifugal casting combined with investment casting or die casting. In addition to numerous design and casting process parameters, heat treatments and alloying additions (Al, Mo, B) were varied to determine the influence of alloying elements on castability, microstructure and mechanical properties. Data from microstructure analyses (microscopic imaging, determination of grain sizes as well as phase compositions and volume fractions, fractography), mechanical tests (hardness measurements, compression tests, ambient and high-temperature tensile tests, creep tests) as well as measurements of thermophysical properties could be generated on the base alloy. Correlations of materials data with process variables allowed conclusions to be drawn on strengthening mechanisms and ductility of the alloy and how they can be controlled in terms of processing and component design. Successful casting of highly complex components with thin wall thicknesses and optimised alloy compositions points out prospects for new fields of application. T2 - FVV Transfer + Netzwerktreffen | Informationstagung – Frühjahr 2023 CY - Würzburg, Germany DA - 29.03.2023 KW - Fe-Al alloys KW - Intermetallics KW - Iron aluminides KW - Microstructure-property-correlation KW - High temperature mechanical properties KW - Creep data KW - Tensile data KW - Fractography KW - Casting PY - 2023 AN - OPUS4-57248 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Beygi Nasrabadi, Hossein T1 - Materials Mechanical Testing Ontology (MTO) N2 - The materials mechanical testing ontology (MTO) was developed by collecting the mechanical testing vocabulary from ISO 23718 standard, as well as the standardized testing processes described for various mechanical testing of materials like tensile testing, Brinell hardness test, Vickers hardness test, stress relaxation test, and fatigue testing. Confirming the ISO/IEC 21838-2 standard, MTO utilizes the Basic Formal Ontology (BFO), Common Core Ontology (CCO), Industrial Ontologies Foundry (IOF), Quantities, Units, Dimensions, and data Types ontologies (QUDT), and Material Science and Engineering Ontology (MSEO) as the upper-level ontologies. Reusing these upper-level ontologies and materials testing standards not only makes MTO highly interoperable with other ontologies but also ensures its acceptance and applicability in the industry. MTO represents the mechanical testing entities in the 230 classes and four main parts: i) Mechanical testing experiments entities like tensile, hardness, creep, and fatigue tests as the subclasses of mseo:Experiment, ii) Mechanical testing quantity concepts such as toughness, elongation, and fatigue strength in the appropriate hierarchies of bfo:Disposition and bfo:Quality classes, iii) Mechanical testing artifacts like indenter as the subclasses of cco:Artifact, and iv) mechanical testing data like the stress-strain, S-N, or creep curves as the subclasses of cco:InformationContentEntity. MTO is publicly available via the KupferDigital GitLab repository. T2 - FEMS EUROMAT 2023 CY - Frankfurt a. M., Germany DA - 03.09.2023 KW - Mechanical testing KW - Ontology KW - Standard PY - 2023 AN - OPUS4-58270 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Manzoni, Anna Maria T1 - Mechanical performance and integrity of tungsten inert gas (TIG) welded CoCrFeMnNi high entropy alloy with austenitic steel AISI 304 N2 - High entropy alloys (HEA) are a new class of materials that have been investigated since the early 2000s and offer great potential to replace conventional alloys. However, since they sometimes have significant contents of expensive alloying elements such as Co or Ni, their use is only conceivable in highly stressed areas of components. For this purpose, the weldability with conventional alloys such as high-alloy austenitic steels must be investigated. In addition to the resulting microstructure, the mechanical properties are also fundamental for the usability of HEAs in DMWs. For this purpose, TIG welds of CoCrFeMnNi HEA (cold rolled and recrystallized state) with AISI 304 austenitic steel are investigated. These mechanical properties are analyzed in this work by means of tensile tests and local hardness measurement. The local strain behavior of the welded joints is also characterized by means of Digital Image Correlation (DIC). The results of the local hardness measurement show a clear influence of the initial condition of the HEA on the HAZ. Thus, the HEA in the cold-rolled condition shows a clear softening because of recrystallization processes in the HAZ. On the other hand, there is no influence on the hardness of the weld metal, which is approx. 200 HV0.1 in both cases. The tensile tests show a consistent failure of the weld in the weld metal. However, regardless of the HEA condition, strengths in the range of the recrystallized HEA (RM ~ 550–600 MPa) are achieved, although with significantly reduced fracture elongations. T2 - International Conference on High-Entropy Materials (ICHEM 2023) CY - Knoxville, TN, USA DA - 18.06.2023 KW - Multi-principal element alloys KW - Welding KW - Mechanical properties KW - Dissimilar metal weld KW - Digital image correlation PY - 2023 AN - OPUS4-57713 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ferrari, Bruno T1 - Microstructural evolution of PBF-LB/M Inconel 718 during solution-aging heat treatments - an in-situ x-ray diffraction study N2 - Inconel 718 (IN718) is a traditional age-hardenable nickel-based alloy that has been increasingly processed by additive manufacturing (AM) in recent years. In the as-solidified condition, IN718 exhibits chemical segregation and the undesired Laves phase, requiring a solution annealing (SA) prior to aging. The material produced by AM does not respond to the established thermal routines in the same way as conventionally produced IN718, and there is still no consensus on which routine yields optimal results. This work aims to provide a fundamental understanding of the heat treatment (HT) response by continuously monitoring the microstructural evolution during SA via time-resolved synchrotron x-ray diffraction, complemented by ex-situ scanning electron microscopy (SEM). The samples were produced by laser powder bed fusion to a geometry of 10x20x90 mm³, from which Ø1x5 mm³ cylindric specimens were extracted. Two different scanning strategies – incremental 67° rotations, Rot, and alternating 0°/67° tracks, Alt – were used, leading to two different as-built conditions. 1-hour SAs were carried out in the beamline ID22 of the ESRF at 50 KeV. Two SA temperatures, SA1 = 1020 °C, and SA2 = 1080 °C were tested for each scanning strategy. Data were processed using the software PDIndexer. In the as-built state, all samples showed typical subgrain columnar cell structures with predominant Nb/Mo segregation and Laves phase at the cell walls, as seen by SEM. The Alt scan induced higher intensity on the Laves peaks than the Rot scan, suggesting a greater content of Laves. Chemical homogenization in the SA was largely achieved during the heating ramp (Fig. 1). SA2 eliminated the Laves peaks just before reaching 1080 °C, and mitigated differences between Rot and Alt samples. On the other hand, SA1 induced the precipitation of the generally detrimental δ phase, also observed by SEM. Furthermore, the Rot scan showed higher δ peak intensities than the Alt scan, indicating a higher content of δ in the latter. No signs of recrystallization were observed in any of the investigated SAs. T2 - FEMS EUROMAT 2023 CY - Frankfurt a. M., Germany DA - 03.09.2023 KW - Additive Manufacturing KW - X-Ray Diffraction KW - Inconel 718 KW - Heat Treatments KW - Microstructure PY - 2023 AN - OPUS4-58392 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kilo, M. T1 - New Approaches for the Preparation and Characterisation of New Glasses N2 - The new robot-assisted glass melting device at BAM is presented by the manufacturing team within the joint project GlasDigital together with an automatic thermo-optical measurement technique. T2 - UST-DGG joint meeting CY - Orléans, France DA - 23.05.2023 KW - Glass melting KW - Thermo-optical measurement PY - 2023 AN - OPUS4-58733 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kilo, M. T1 - New Approaches for the Preparation and Characterisation of New Glasses N2 - The new robot-assisted glass melting device at BAM is presented by the manufacturing team within the joint project GlasDigital together with an automatic thermo-optical measurement technique. T2 - USTV-DGG joint meeting CY - Orleans, France DA - 22.05.2023 KW - Glass KW - Robotic melting PY - 2023 AN - OPUS4-60374 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bayerlein, Bernd T1 - News from the working area - Semantic Interoperability N2 - This presentation provides a comprehensive overview of recent developments and the current status within the Semantic Interoperability work area, with a particular emphasis on the advancements related to the Platform MaterialDigital Core Ontology (PMDco). The presentation will delve into the collaborative and community-supported curation process that has been instrumental in shaping PMDco. Additionally, we will introduce the innovative Ontology Playground, showcasing its role in fostering experimentation and exploration within the realm of ontology development. T2 - MaterialDigital Vollversammlung CY - Karlsruhe, Germany DA - 21.09.2023 KW - Semantic Representation KW - FAIR data management KW - Semantic Interoperability KW - Knowledge graph and ontologies KW - PMD Core Ontology KW - MaterialDigital PY - 2023 AN - OPUS4-58422 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jentzsch, Stefan T1 - Numerical and experimental investigations on metal shear band formation at high strain rates with a Hopkinson bar setup N2 - The essence of dynamic failure is closely linked to the formation of adiabatic shear bands (ASB), which result from the localization of shear strain under high deformation speeds accompanied by a rapid temperature increase. Understanding this phenomenon is crucial in view of safety issues when impacts of fast rotating machine components (i.e. aircraft turbine blades) may occur. Our contribution addresses both the experimental evidence and characterization of ASBs due to high-speed impact tests at the Split HOPKINSON pressure bar (SHPB) setup and the finite element analysis to determine the parameters of the underlying constitutive model, which is closely related to JOHNSON-COOK (JC) material model. Experimental investigations were performed on notched shear specimens made of the fine -grained structural steel S690QL and the displacements in the regions affected by shear localization were measured with subset-based local Digital Image Correlation (DIC). The displacement fields, obtained in the SHPB tests, were considered as an objective to validate and to identify the constitutive parameters with. The JC model could reasonably reproduce the displacement distribution. In order to overcome the issues with mesh dependency we provide a nonlocal extension based on the implicit gradient model approach. T2 - GAMM Annual Meeting 2023 CY - Dresden, Germany DA - 30.05.2023 KW - Gradient-enhanced damage KW - Adiabatic shear bands KW - Split Hopkinson bar KW - Digital image correlation KW - Viscoplasticity KW - Finite element analysis PY - 2023 AN - OPUS4-57827 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Maaß, Robert T1 - On an experimentalist's hard search for free volume N2 - This talk was given in honor of Prof. Frans Spaepen, faculty at Harvard University, at the occasion of his Staudinger Lecture and his honorary doctorate degree reception at ETH Zurich. It covers a 10 year long journey of how an experimentalist probes free-volume effects in metallic glasses. T2 - Symposium in honor of Frans Spaepen Honorary Doctorate ETH Zurich CY - Zurich, Switzerland DA - 08.12.2023 KW - Metallic glass KW - Deformation KW - Shear bands PY - 2023 AN - OPUS4-60717 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Maaß, Robert T1 - On an unusual career path and unusual transport in metallic glasses N2 - Planning an academic career is a bit like enjoying a box of chocolate – you never know what you are going to get next. In this talk, I will begin with sharing how luck, difficult decisions, fate, and family constraints affected my career path across continents, universities, the private sector, and to becoming a director at a national laboratory. This journey was certainly not planned and highlights how opportunities and compromises together allow you to make much more out of your engineering degree than you ever have dreamed of. After this unusual journey as a materials scientist, I am transitioning to the technical part of my talk, where we will discuss transport in metallic glasses. This out-of-equilibrium material has a long suite of remarkable mechanical and physical properties but suffers from property deterioration via physical aging. As a function of time, relaxation may indeed constitute significant threads to safe applications, such as a complete loss of toughness. In the search for a physical understanding of aging, we exploit here the ability to track atomic-scale dynamics with coherent x-ray scattering. Conducted across temperatures and under the application of stress, the results reveal unexpected transport. In concert with microsecond molecular dynamic simulations, we identify possible mechanisms of atomic-scale dynamics that underly physical aging of metallic glasses. We find that classical Kohlrausch-Williams-Watts behavior is only suited for the short relaxation-time regime, whereas anomalous diffusion emerges at practically relevant times. We discuss these results in terms of the structural relaxation modes and propose a picture of a true microstructure in metallic glasses. T2 - Department Seminar IIT Delhi 2023 CY - Delhi, India DA - 15.12.2023 KW - Metallic glass KW - Transport KW - Structure KW - Dynamics PY - 2023 AN - OPUS4-60649 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF 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. T2 - ICMMM 2023: 10th International Conference on Mechanics, Materials and Manufacturing CY - Washington, D.C., USA DA - 18.08.2023 KW - Ontology KW - Knowledge graph KW - Data mapping KW - Vickers hardness KW - FAIR data PY - 2023 AN - OPUS4-58100 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - de Camargo, Andrea Simone Stucchi T1 - Optical properties of dental ceramics: Characterization via UV-Vis and photoluminescence spectroscopies N2 - When it comes to dental treatments, success is not only measured by attained functionality but, to a large extent, the associated aesthetics. This can become challenging for certain restorations and implants due to the complex optical characteristic of a tooth, which reflects, absorbs, diffuses, transmits, and even emits light. Thus, to get acceptable aesthetic results, favourable shade matching of ceramic restorations and implants should be achieved by strict control of optical response, which translates into a materials design question. Optical response is affected by several factors such as the composition, crystalline content, porosity, additives, grain size and the angle of incidence of light on the dental ceramics. The properties to be characterized are colour (and its stability), translucency, opalescence, refractive index, and fluorescence. Several techniques can be applied for the characterization of these properties and in this presentation, an overview will be given. Moreover, particular emphasis will be given on the capacitation of less familiarized public to UV-Vis absorption and photoluminescence (PLE) spectroscopies that are versatile and widely employed for functional and structural characterization of glasses and glass ceramic materials. T2 - 2nd BAYLAT Workshop of CERTEV - FAU CY - Nuremberg, Germany DA - 04.12.2023 KW - Optical properties KW - Dental ceramics KW - Optical spectroscopy PY - 2023 AN - OPUS4-60364 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -