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- 9.4 Integrität von Schweißverbindungen (355)
- 7.6 Korrosion und Korrosionsschutz (352)
The hydrogen economy is one of the main solutions for achieving climate neutrality in Europe. Metallic materials, predominantly steels, are the most common structural materials in the various components along the hydrogen supply chain. Ensuring their sustainable and safe use in hydrogen technologies is a key factor in the ramp-up of the hydrogen economy. This requires extensive materials qualification, however, most of the accepted, and standardised test methods for determining the influence of gaseous hydrogen on metallic materials describe complex and costly procedures that are only available to a very limited extent worldwide (e.g., autoclave technique).
The hollow specimen technique is presented as an alternative method that can overcome the limitations of current techniques and complement them. To standardise the technique, a process has been initiated by ISO in 2021. Knowledge gaps for tests with the technique in hydrogen have been identified by DIN. The H2HohlZug project, which falls under the umbrella of TransHyDE, aims to address the identified knowledge gaps and provide a foundation for a comprehensive standardisation of the hollow specimen technique.
Im Rahmen des 2. BAM-Akademie Info-Tages "Nano or not Nano" wurde die OECD TG 124 "Volume Specific Surface Area of Manufactured Nanomaterials" vorgestellt. Der Vortrag beschreibt detailliert das Messverfahren der He-Gaspyknometrie zur Bestimmung der Skelettdichte von Pulvern und geht auf Anwendbarkeit, Besonderheiten bei Nanopulvern und wichtige Einstellparameter für die Messung ein.
Die Erzeugung rissschließfreier Anrisse in gekerbten bruchmechanischen Proben für anschließende Ermüdungsversuche kann durch eine zyklische Druckbelastung an der Kerbe erfolgen: Bei der Erstbelastung wird eine plastische Verformung an der Kerbspitze erzeugt, welche Zugeigenspannungen und damit eine risstreibende Kraft bei der folgenden zyklischen Druckbelastung hervorruft. Durch das Risswachstum kommt es zu einer Entspannung, bis der Riss schließlich arretiert, weil die effektive risstreibende Kraft auf den Schwellenwert abgesunken ist. Um Kurzrisswachstum in additiv, mittels pulverbettbasiertem Laserstrahlschmelzen (Laser Powder Bed Fusion - LPBF) gefertigtem AISI 316L Stahl und seinem konventionell erzeugten, warmgewalzten Pendant zu untersuchen, wurde dieses Verfahren im Rahmen der vorliegenden Arbeit genutzt. Im Falle des additiv gefertigten Materials kam es zu unerwartet langem Ermüdungsrisswachstum, bevor der Riss arretierte. Zur Ermittlung der Ursache erfolgte eine Messung der Eigenspannungsverteilungen mittels Neutronendiffraktion in der Kerbebene der additiv gefertigten Proben. Anschließend wurde ein Finite-Elemente-Modell zur Simulation des Ermüdungsrisswachstums in konventionellem und additiv gefertigtem Material implementiert. Im Rahmen dieses Vortrages wird insbesondere auf das Vorgehen bei der Simulation und auf die getroffenen Annahmen und Vereinfachungen eingegangen. Die Resultate werden mit den experimentellen Ergebnissen verglichen und das für die Simulation von Risswachstum genutzte Knoten-Freigabe-Verfahren (Node-Release), das Einbringen von Eigenspannungen als initiale Spannungen in der Simulation, und die Rechengrößen zur Quantifizierung der risstreibenden Kraft kritisch diskutiert.
Korrosionsprüfung
(2024)
Der Vortrag gibt einen Überblick über gängige Korrosionsversuche. Die wesentlichen Unterschiede zwischen Prüf- und Untersuchungsverfahren, deren jeweilige Zielstellung, Aussagefähigkeit und Grenzen werden aufgezeigt. Es werden ausgewählte Auslagerungsversuche, Kammerprüfungen sowie elektrochemische Messmethoden zur Bestimmung der Korrosionsbeständigkeit vorgestellt. Anhand praktischer Beispiele werden ausgewählte Ergebnisse der einzelner Methoden vorgestellt und diskutiert.
Einführungsvortrag im Rahmen der Veranstaltung der BAM-Akademie zur Anwendung der OECD TG 124 "Volume Specific Surface Area of Manufactured Nanomaterials" zu Herausforderungen bei der Granulometrie von Nanopulvern. Es werden die Einflüsse von Partikelform, Breite der Partikelgrößenverteilung und Agglomeration/ Aggregation auf das Messergebnis sowie die Vergleichbarkeit der Ergebnisse verschiedener Messverfahren dargelegt.
Übersichtsvortrag zu Korrosionsarten, die bei nichtrostenden Stählen unter verschiedenen Einsatzbedingungen auftreten können. Die Grundlagen zur Pasivität und der örtlichen Störung der Passivität werden im Zusammenspiel komplexer Einflussfaktoren des Korrosionssystems herausgestellt. Die erarbeiteten theoretischen Grundlagen werden anhand praktischer Beispiel für alle relevanten Korrosionsarten vertieft.
Der Vortrag behandelt den Stand der Technik bei der zerstörungsfreien Prüfung von Betonkonstruktionen und insbesondere den Stand und die Herausforderungen bei der Digitalisierung. Es werden Prüfaufgaben sowie etablierte Prüfmethoden und die passende Auswahl diskutiert. Ein weitere Schwerpunkt liegt bei der Genauigkeit und Verlässlichkeit und dem Konzept ZfPStatik. Abschließend werden Schnittstellen zu BIM, SIB-Bauwerke und anderen System kurz angerissen und ein Katalog offener Fragen aufgestellt.
Bonds and local atomic environments are crucial descriptors of material properties. They have been used to create design rules and heuristics and as features in machine learning of materials properties. Implementations and algorithms (e.g., ChemEnv and LobsterEnv) for identifying local atomic environments based on geometrical characteristics and quantum-chemical bonding analysis are nowadays available. Fully automatic workflows and analysis tools have been developed to use quantum-chemical bonding analysis on a large scale. The lecture will demonstrate how our tools, that assess local atomic environments and perform automatic bonding analysis, help to develop new machine learning models and a new intuitive understanding of materials.[5,6] Furthermore, the general trend toward automation in density functional-based materials science and some of our recent contributions will be discussed.
Sunlight is an almost unavoidable environmental cue and plays a fundamental role in the biology of pro- and eukaryotic organisms. To cope with sunlight-associated stresses e.g., high temperatures, UV radiation, accumulation of reactive oxygen species, desiccation, and osmotic stress, it is important for organisms to accurately sense and respond to changes in light. The benefits of light are obvious for green organisms such as cyanobacteria, algae and plants which use light as an energy source (photosynthesis). Fungi that can share light-flooded habitats with phototrophs may profit from their excess photosynthetic products. Examples are the plant pathogen Botrytis cinerea, the gray mold fungus, and the rock inhabitant Knufia petricola, a microcolonial black fungus which forms multispecies biofilms with bacteria and algae.
Highly unrelaxed structural states of metallic glasses have often advantageous mechanical properties. Since metallic glasses continuously relax with time (age) or inherently are well relaxed after processing, methods to uniformly rejuvenate the material are needed. One approach that has received attention is the so-called cryogenic-cycling method, during which a metallic glass is repeatedly immersed into liquid nitrogen. In some cases, cryogenic cycling is truly efficient in increasing the stored excess enthalpy of metallic glasses, but it does not seem to be universally applicable to all alloys and structural states. The origins for these differences remain unclear due to our limited understanding of the underlying structural evolution. In order to shed more light onto the fundamental structural processes of cryogenic cycling, we pursue in-situ x-ray photon correlation spectroscopy (XPCS) to trace the atomic-scale structural dynamics of a Zr-based metallic glass in two different structural states (ribbon and bulk metallic glass). This method allows calculating the relaxation times as a function of time throughout the thermal cycling. It is found that the investigated glasses exhibit heterogeneous structural dynamics at 300 K, which changes to monotonic aging at 78 K. Cryogenic cycling homogenizes the relaxation time distribution for both structural states. This effect is much more pronounced in the ribbon, which is the only structural state that rejuvenates upon cycling. We furthermore reveal how fast atomic-scale dynamics is correlated with long-time average structural relaxation times irrespective of the state, and that the ribbon exhibits unexpected additional fast atomic-scale relaxation in comparison to the plate material. Overall, a picture emerges that points towards heterogeneities in fictive temperature as a requirement for cryogenic energy storage.
This presentation discusses the potentials of probabilistic methods in offshore foundation installation, from the perspective of probabilistic ground models and data-driven site characterization. We discuss about methodologies for utilizing site-specific geotechnical (CPT) and geological data, aiming to construct an integrated ground model that can predict stratigraphic profiles and useful for geotechnical design parameters at any location within a 3D domain. The predicted parameters and stratigraphy are then used to predict the probability of potential pile tip damage, upon collision with a boulder.
Korrosion und Korrosionsschutzverfahren: Teil 1 Grundlagern der Korrosion metallener Werkstoffe
(2024)
Der Übersichtsvortrag vermittelt Kenntnisse zu den Grundlagen der Korrosion metallischer Werkstoffe für das KKS Grundlagenseminar für erdverlegte Anlagen und Stahlbetonbau zur Vorbereitung auf die Zertifikatsprüfung DIN EN 15257. Diese Kenntnisse bilden die Grundlage zum Verständnis der Beeinflussung von Korrosionssystemen durch die Anwendung kathodischer Schutzmaßnahme
Der Vortrag thematisiert die Grundlagen des Korrosionsschutzes. Dieser kann planungs-,werkstoff oder mediumsseitig erfolgen oder mit elektrochemischen Methoden umgesetzt werden. Der Vortrag beschreit die Korrosivitäten der Atmosphären und welche Maßnahmen für den Korrosionsschutz daraus abgeleitet werden können.
Forschungsvorhaben RUNOFF
(2024)
Offshore wind energy plays an important role for the desired transition towards a carbon dioxide free industry within the next decades. However, the grounding of the offshore wind plants governs the overall installation process besides bureaucratic bottlenecks.
The application of lightweight principles in steel construction, e.g. the usage dissolved load-bearing structures, so called Jackets foundations, offer great potential in reducing the resource consumption, especially with respect to the needed amount of steel.
In this context this paper focuses on a fully digitalization of the welding manufacturing and as well as testing chain to enable a fully automated manufacturing as well as quality assessment of tubular nodes as key element of Jackets foundation structures. Furthermore, the relationship between the seam shape geometry and resulting fatigue strength is evaluated by numerical methods incorporating bionic principles. It is shown that tubular nodes can be welded fully automatically taking geometry tolerances into account. Moreover, the seam shape could be manufactured as requested by the numerical models which offers great potential for an extended lifetime. Subsequently, the improvements in resource efficiency and reduction of carbon dioxide emissions are evaluated by a life-cycle-assessment.
Direct energy deposition additive manufacturing technologies utilizing an electric arc offer a great potential in generating large volume metal components. However, the selection of process parameters that yield the desired near net shape design as well as the requested mechanical component behavior is not a trivial task due to the complex relationship. Exemplarily for additive manufacturing of high-strength precipitation hardening AlMgSi-aluminum alloy this paper shows the application of a newly developed matching solid welding wire doped with TiB as grain refiner. The correlation between process parameters and component quality is examined analyzing the size and distribution of pores as well as the grain morphology. Furthermore, the influences of different post-weld heat treatments are evaluated to meet the reference mechanical properties of the corresponding wrought material. Finally, the digital integration of the entire additive manufacturing chain enables an overall traceability of the relevant process steps which is the basis for a reliable subsequent quality assessment.
In manufacturing, fusion welding processes use a lot of resources, which presents an opportunity to reduce environmental impact. While there is a general understanding of the environmental impact of these processes, it is difficult to quantitatively assess key parameters. This study introduces a welding-specific methodology that uses life cycle assessment (LCA) to evaluate the environmental impact of fusion welding technologies. Our approach analyses the main parameters that affect the environmental performance of different welding techniques, including traditional methods and additive manufacturing through the Direct Energy Deposition-Arc (DED-Arc) process. We integrate real-time resource usage data to offer an innovative framework for directly deriving environmental impacts. This research contributes to optimising welding processes by providing a precise and quantifiable measure of their ecological impact, facilitating the advancement of sustainable manufacturing practices.
In industrialised countries more than 80% of the time is spent indoors. Products, such as building materials and furniture, emit volatile organic compounds (VOCs), which are therefore ubiquitous in indoor air. VOC in combination may, under certain environmental and occupational conditions, result in reported sensory irritation and health complaints. Emission concentrations can become further elevated in new or refurbished buildings where the rate of air exchange with fresh ambient air may be limited due to improved energy saving aspects. A healthy indoor environment can be achieved by controlling the sources and by eliminating or limiting the release of harmful substances into the air. One way is to use (building) materials proved to be low emitting. Meanwhile, a worldwide network of professional commercial and non-commercial laboratories performing emission tests for the evaluation of products for interior use has been established. Therefore, comparability of test results must be ensured. A laboratory’s proficiency can be proven by internal and external validation measures that both include the application of suitable emission reference materials (ERM). For the emission test chamber procedure according to EN 16516, no artificial ERM is commercially available. The EU-funded EMPIR project MetrIAQ aims to fill this gap by developing new and improved ERMs. The goal is to obtain a material with a reproducible and temporally constant compound release (less than 10 % variability over 14 days). Two approaches were tested: the impregnation of porous materials with VOC, and the encapsulation of VOC in polymer microcapsules. Impregnation is performed with help of an autoclave and supercritical CO2. The encapsulation is done by interfacial polymerisation on VOC droplets. For both approaches, synthesis and/or material parameters were varied to obtain an optimal ERM. Findings about the optimisation of ERM generation, as well as performance of the best emission reference materials, will be presented.
Die Offshore-Windenergie spielt eine wichtige Rolle beim angestrebten Übergang zu einer emissionsfreien Industrie während der nächsten Jahrzehnte. Allerdings beeinflusst die Gründung der Offshore-Windanlagen den gesamten Installationsprozess. Die Anwendung von Leichtbauprinzipien im Stahlbau, wie beispielsweise die Verwendung von aufgelösten Tragstrukturen, sogenannten Jacket-Fundamenten, bietet ein großes Potenzial zur Reduzierung des Ressourcenverbrauchs, insbesondere im Hinblick auf die benötigte Stahlmenge. Der Vortrag befasst sich daher mit der vollständigen Digitalisierung der schweißtechnischen Fertigungs- und Prüfkette. Ziel ist es, eine vollautomatische Fertigung sowie Qualitätsprüfung von Rohrknoten zu ermöglichen. Diese stellen ein Schlüsselelement von Jacket-Fundamenten dar. Des Weiteren wird der Zusammenhang zwischen der Geometrie der Schweißnaht und der resultierenden Ermüdungsfestigkeit durch numerische Methoden unter Einbeziehung bionischer Prinzipien bewertet. Es wird gezeigt, dass rohrförmige Knoten unter Berücksichtigung von Geometrietoleranzen vollautomatisch geschweißt werden können. Die Schweißnahtform konnte gemäß den numerischen Modellen hergestellt werden, was ein großes Potenzial für eine verlängerte Lebensdauer bietet. Anschließend erfolgt eine Bewertung der Verbesserungen bei der Ressourceneffizienz und der Verringerung des CO2-Fußabdrucks durch ein Life Cycle Assessment.
The principles of (Hard) X-ray photoelectron spectroscopy and some application in the field of (core-shell) nanoparticles will be presented. The presentation should answer hoe to get reliable results. Furthermore, examples of the correlation between physical-chemical measurments and toxicological results are given which are crucial for the risk assessment of nanoparticles.
Life cycle assessment of fusion welding processes considering upstream and downstream process steps
(2023)
In manufacturing, fusion welding processes consume significant resources, presenting a significant opportunity for reducing environmental impact. Although there is a qualitative understanding of the environmental implications of these processes, a quantitative assessment of key parameters remains complex. This study introduces a welding-specific methodology that employs life cycle assessment (LCA) to quantitatively evaluate the environmental footprint of fusion welding technologies. Our approach identifies and analyses the principal parameters affecting the environmental performance of various welding techniques, including traditional joint welding and additive manufacturing via the Direct Energy Deposition-Arc (DED-Arc) process. Real-time resource usage data is integrated to offer an innovative framework for directly deriving environmental impacts. This research contributes to optimising welding processes by providing a precise and quantifiable measure of their ecological impact. This facilitates the advancement of sustainable manufacturing practices.
Mit dem Klimawandel verändert sich nicht nur das Wetter, also Regenmengen, Temperaturen oder Starkwind- bzw. Sturmzeiten. Mit diesen Veränderungen gehen auch Veränderungen der örtlichen Korro-siviät der Atmosphäre einher. Sind die Datengrundlagen der aktuellen nationalen und internationalen Normen mit Datenerhebungen aus den 1970igern und 80iger Jahren noch repräsentativ? Hierzu werden an realen Offshorestrukturen valide Daten erfasst, die als Grundlage für KI-basierte Modellbildung verwendet werden sollen.
Im Verbundprojekt R-Rhenania wird eine industrielle Demonstrationsanlage am Standort der Monoverbrennungsanlage Altenstadt der Firma Emter errichtet und im Jahr 2024 den Betrieb aufnehmen. Die vorhandene Rostfeuerung-Monoverbrennung wird so umgebaut, dass ein neues thermochemisches Verfahren integriert werden kann, welches hochwirksame und schadstoffarme Dünger produziert (bis zu 17.000 t/a). Die thermochemischen Produkte werden in Gefäß- und Feldversuchen im ökologischen Landbau auf ihre Düngewirkung getestet. Die Umweltverträglichkeit der Demonstrationsanlage wird untersucht, wie auch die Übertragbarkeit des Verfahrens auf weitere Regionen.
Der Beitrag zeigt die Mechanismen, Voraussetzungen und Einflussgrößen der Bimetallkorrosion wichtiger Werkstoffe im Kontakt mit nichtrostenden Stahl anhand von verschiedenen Beispielen. Darüber hinaus wird das Korrosionsverhalten von nichtrostenden Stahl im Kontakt mit Holz als saurer Baustoff und mit Beton als alkalischer Baustoff beschrieben.
Demonstrationsexperimente
(2024)
The subject of permeation of hoses according to ISO 3821 for
hydrogen was discussed for a long time in ISO/TC 44/SC 8. The reason
is a considerable leakage of hydrogen diffused into the hose material
over the end face of the hose. Because of this unsolved, safety-related
problem of hoses sold on the market, measurements should be carried
out in order to be able to better assess the problem. BAM has declared
its attendance to provide a required fast solution to this issue.
Zur Erweiterung der Anwendungserfahrungen nichtrostender Stähle, insbesondere von Lean-Duplex-Stählen, unter maritimen Einsatzbedingungen, wurden Testracks auf der Umspannplattform OSS des Windparks Hohe See errichtet. Hier wurden neben Standardproben zur Korrosivitätsbestimmung nach ISO 9223 auch mehrere Serien nichtrostender Stahlgüten mit unterschiedlichen Oberflächen, Spaltausbildungen und Verarbeitungszuständen ausgelagert und nun nach 1-jähriger Bewitterungszeit bewertet. In diesem Beitrag werden Oberflächenzustände, Korrosionszustände und Lochtiefen dieser Probekörper gezeigt.
Zur Umsetzung der wasserstoffbasierten Energiewende ist eine zuverlässige Transportinfrastruktur unverzichtbar. Hierfür ist die Nutzung großer Teile des vorhandenen Erdgasnetzes vorgesehen. Im Rahmen von Reparatur- und Wartungsarbeiten ist das Schweißen im Betrieb an Erdgaspipelines Stand der Technik. In Verbindung mit Wasserstoff wirft diese Technik jedoch Fragen der Materialverträglichkeit auf. Das im Vortrag vorgestellte Projekt H2SuD leistet Beiträge zur Aufklärung des Einflusses von Reparaturschweißprozessen auf die Wasserstoffaufnahme und Degradation im Betrieb befindlicher H2 Gasleitungen. Ein Schwerpunkt des Vortrages liegt auf der im Projekt erarbeiteten Prüfmethode für Modellversuche, mit denen der Einfluss von Schweißen im Betrieb an Pipelines auf die Wasserstoffaufnahme getestet wird. Die Durchführung erster Versuche und dabei erzielte Ergebnisse werden präsentiert.
Climate change and increasing demand for electricity require the use of power electronics based on new wide bandgap (WBG) compound semiconductors. Power electronics devices are used in numerous application areas to control and convert electric energy. These may include generation and distribution of renewable energy for green hydrogen, electrification of transport or 5G communication. WBG electronics have much higher efficiency than the silicon-based ones and can operate at higher power densities, voltages, temperatures and switching frequencies with low energy losses. However, defects in the semiconductors can considerably affect the performance of power electronic devices or make their operation even impossible. The presentation will show the application of spectroscopic and imaging ellipsometry as well as white light interference microscopy for defect characterisation in SiC, GaN and Ga2O3 over a wide wavelength range.
We used parameterized modelling of ellipsometric transfer parameters to determine the dielectric properties of bulk materials and thin layers. Imaging ellipsometry offers more information and is an advanced variant of optical microscopy, combining the lateral resolution of optical microscopy with the extreme sensitivity to surface and interface effects of ellipsometry. Surface topography and morphology of different types of defects were additionally investigated with imaging white light interference microscopy. Modern electronic thin film components require complex surface analysis methodologies and hybrid metrology. Hybrid measurement techniques enable fast and non-destructive traceable characterisation of thin film compound semiconductors as well as accurate detection and identification of defects. This methodical approach leads to a better understanding of the materials themselves and of the defect formation mechanisms during manufacturing.
This work aims to enable highly reproducible manufacturing of compound semiconductor power electronics as well as operation monitoring to ensure failure-safety of electronic systems in power electronic devices.
Bei Geräten und Maschinen zur bestimmungsgemäßen Verwendung in explosionsgefährdeten Bereichen gemäß 2014/34/EU muss in der europäischen Union eine Zündgefahrenbewertung durchgeführt werden. Dabei müssen unter anderem die Gefahren von nichtelektrischen Zündquellen betrachtet werden, zu denen auch die mechanischen Schlagvorgänge gehören.
Bei mechanisch erzeugten Schlag-, Schleif- und Reibvorgängen kommt es infolge des Zusammenstoßes bzw. des Reibens zweier Werkstücke bzw. Bauteile zu einer Umwandlung der kinetischen Energie. Dabei erhöht sich die Temperatur der Werkstoffe an der Kontaktstelle und es kommt unter Umständen zu einem Abtrennvorgang kleiner Partikel erhöhter Temperatur. Sowohl die heißen Kontaktstellen (Zündquelle "heiße Oberflächen") als auch die abgetrennten Partikel (Zündquelle "mechanisch erzeugte Funken") können eine wirksame Zündquelle für ein explosionsfähiges Gasgemisch darstellen.
Zur Festlegung von Grenzwerten wurden in der Norm DIN EN ISO 80079-36:2016 die Gasgemische anhand ihrer Explosionsgruppe klassifiziert und zu jeder Gruppe die maximale Energie des Schlagvorgangs festgelegt, unter derer die Entstehung einer wirksamen Zündquelle als unwahrscheinlich angenommen werden kann.
Ferner finden sich in der TRGS 723 Hinweise zum Umgang mit funkenarmen Werkzeugen im explosionsgefährdeten Bereich.
An overview of personal experience with laser-induced plasma (LIP) will be given. The combination of LIP with laser-induced fluorescence, atomic absorption, Raman spectroscopy and spatial heterodyne spectroscopy for elemental and isotopic analysis will be discussed. Unusual applications of LIP will be covered, such as LIP-based lasers and LIP-based chemical reactors.
This course will provide an introduction to plasma diagnostic techniques. The major focus of the course will be on the discussions of the practical procedures as well as the underlying physical principles for the measurements of plasma fundamental characteristics (e.g., temperatures, thermodynamic properties, and electron number density). Particular emphasis will be placed on inductively coupled plasma–atomic emission spectrometry, but other analytical plasmas will also be used as examples when appropriate. Selected examples on how one can manipulate the operating conditions of the plasma source, based on the results of plasma diagnostic measurements, to improve its performance used for spectrochemical analysis will also be covered. Topics to be covered include thermal equilibrium, line profiles, temperatures, electron densities, excitation processes, micro reactions, pump and probe diagnostics, tomography,
temporal and spatial resolution. Basis of plasma computer modeling will be presented.
Die Material Acceleration Platform der BAM (MAPz@BAM) bündelt unsere Automatisierungs-Expertise auf dem Gebiet der Materialwissenschaft und -prüfung. Wir entwickeln modulare Experimentmodule, automatische Prüf- und Auswerteverfahren und setzen künstliche Intelligenz für eine effiziente und autonome Versuchsplanung, - vorhersage und Datenanalyse ein.
Die Material Acceleration Platform der BAM (MAPz@BAM) bündelt unsere Automatisierungs-Expertise auf dem Gebiet der Materialwissenschaft und -prüfung. Wir entwickeln modulare Experimentmodule, automatische Prüf- und Auswerteverfahren und setzen künstliche Intelligenz für eine effiziente und autonome Versuchsplanung, - vorhersage und Datenanalyse ein.
Die Material Acceleration Platform der BAM (MAPz@BAM) bündelt unsere Automatisierungs-Expertise auf dem Gebiet der Materialwissenschaft und -prüfung. Wir entwickeln modulare Experimentmodule, automatische Prüf- und Auswerteverfahren und setzen künstliche Intelligenz für eine effiziente und autonome Versuchsplanung, - vorhersage und Datenanalyse ein.
Mikrolegierungselemente wie Nb und Ti sind entscheidend für die erwünschte mechanische Festigkeit von vergüteten Feinkornbaustählen mit einer Nennstreckgrenze von ≥ 690 MPa. Aktuelle Spezifikationen geben lediglich Obergrenzen für die chemische Zusammensetzung vor, allerdings können geringfügige Abweichungen erhebliche Auswirkungen auf die mechanischen Eigenschaften haben. Die Vorhersage der Schweißbarkeit und Integrität von Schweißverbindungen stellt aufgrund der variierenden Zusammensetzung und Mikrostrukturen Herausforderungen dar. Unerwünschte Effekte wie Erweichung der Wärmeeinflusszone (WEZ) oder Verfestigung können auftreten. Um dies zu untersuchen, wurden verschiedene Mikrolegierungsrouten mit variierenden Ti- und Nb-Gehalten an Laborschmelzen erforscht. Die Basis jeder Route entsprach der üblichen S690QL in Zusammensetzung und Wärmebehandlung. Dreilagenschweißungen wurden mittels Metallaktivgasschweißens (MAG) durchgeführt, um kritische Gefügebereiche zu identifizieren. Die Analyse konzentrierte sich auf Phasenumwandlungen während der Abkühlung und metallurgisches Ausscheidungsverhalten. Die mechanischen Eigenschaften der Schweißnähte wurden durch Zugversuche ermittelt. Die Ergebnisse zeigen einen bedeutenden Einfluss der Mikrolegierungsroute und Schweißwärmezufuhr auf die Ausscheidungskinetik, trotz insgesamt guter Schweißbarkeit der Werkstoffe.
Die Laserbearbeitung von Materialien mit ultrakurzen Laserpulsen kann zu einer sekundären Emission gefährlicher Röntgenstrahlen führen. Dieser Effekt wurde bisher bei der Bearbeitung von technischen Materialien wie Metallen beobachtet. Die Röntgenemission bei der abtragenden Bearbeitung von biologischen Geweben ist noch weitgehend unerforscht. Der Vortrag präsentiert erste Untersuchungen und Ergebnisse des radiologischen Gefährdungspotentials bei der medizinischen Anwendung von Ultrakurzpulslasern am Menschen.
The efficient exploration of novel alloy compositions is crucial for advancing the development of new materials. One widely utilized approach for creating phase diagrams is the use of diffusion-controlled synthesis for gradient alloys. This method is also an effective means for rapidly identifying potential material combinations.
The present study focusses on the exploration of quaternary multi-principle-element alloys (MPEAs) using diffusion multiples. We established a diffusion system by combining an equimolar ternary alloy (FeNiCr) with single diffusing elements Mn and Mo. Using ThermoCalc simulations, we determined suitable temperature ranges where we can expect the formation of single-phase alloys. Depending on the diffusion constants of the selected metals, diffusion times were adjusted to obtain diffusion zones with a depth of greater than 50 μm. Microstructural and compositional information was gathered via scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) and correlated to local mechanical properties evaluated by means of nanoindentation. Local corrosion properties were examined using Atomic Force Microscopy (AFM) and Scanning Electrochemical Microscopy (SECM).
Our results indicate that the ThermoCalc simulations have a good predictive power for crystallographic phases. However, especially with the Mn-FeNiCr system, formation of Cr-rich secondary phases were observed, which led to Cr-depletion and thus to localized corrosion processes in the matrix at the vicinity of the secondary phases. Based on the results of the local electrochemical tests, we have selected single-phase compositions along the diffusion zone and synthesized these alloys in bulk for corrosion studies by means of potentiodynamic polarization and SECM.
The presentation will summarize our methodology using diffusion couples as an
efficient tool for exploring compositional spaces of MPEAs in the search for novel single-phase alloys and the results of our correlative study on the mechanical and corrosion properties of these materials.
The efficient exploration of novel alloy chemistries is crucial for advancing the development of new materials. Diffusion-controlled synthesis of gradient alloys is an intelligent approach for creating phase diagrams and to effectively identify potential material combinations with tailored properties.
This project focusses on the design of quaternary multi-principle-element alloys (MPEAs) using diffusion couples. Our diffusion system contains an equimolar ternary alloy (FeNiCr) and additional single diffusing elements e.g. Mn and Mo. We determined the optimal temperature ranges for the diffusion thermal treatment by means of ThermoCalc simulations with the aim to form single-phase MPEAs. Microstructure and chemical characterization of the diffusion couples were performed by means of scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). For most alloy couples, the diffusion zone contained a single-phase alloy matrix with diffusion-induced compositional gradient as well as precipitation phases. This heterogeneity makes the diffusion couples interesting materials to investigate local mechanical and corrosion properties. Thus, local corrosion properties were examined using Atomic Force Microscopy (AFM) and Scanning Electrochemical Microscopy (SECM). Nanoindentation was used for the analysis of local mechanical properties.
Based on the results of the local corrosion analysis, we have selected single-phase alloy chemistries along the diffusion zone and reproducibly synthesized these alloys in bulk for detailed corrosion studies by means of potentiodynamic polarization and SECM.
The presentation will briefly summarize our methodology and motivation for using diffusion couples as an efficient tool for exploring phase diagrams of MPEAs in the search for new alloy chemistries and the results of our correlative study on the mechanical and corrosion properties of these materials.
Old materials, new life: Using diffusion-controlled synthesis for discovery of novel alloy systems
(2023)
Multi principal element alloy (MPEAs) concept allows us to rethink how we develop application-tailored, sustainable materials. The vast composition space leads to nearly indefinite material combinations and will facilitate finding Pareto optimal materials with lower CO2 footprint and avoidance of critical minerals as design criteria. To probe this large compositional space efficiently, the use high-throughput screening methods is inevitable. Diffusion-controlled synthesis of gradient materials is the optimal technique for screening complex compositional materials that would otherwise require comprehensive modelling or experimental efforts.
In this study, we have used a series of diffusion couples of pure metals and alloys with the aim to create a materials library with correlated data on composition and microstructure. With future recycling prospects in mind, and possible applications of Cu containing alloys in electrocatalytic carbon dioxide reduction and antimicrobial alloys we have generated diffusion couples of brass (Cu63Zn37) and bronze (Cu89Sn11) with either pure metals (Fe, Ni, etc.) or with binary or ternary alloys (FeNi, FeNiCr etc.). For different diffusion times and temperatures, we calculated diffusion constants for the material combinations. Following a detailed characterisation of the gradient materials, we have investigated general and local corrosion properties, electrocatalytic activity for oxygen evolution reaction (OER) and carbon dioxide reduction reaction (CRR) as well as mechanical properties (hardness, elastic modulus) on single-phase alloys synthesized in bulk by means of vacuum arc-melting based on the selected local compositions.
In most cases, due to the short diffusion times, the contact between the diffusion couples lead to two separate diffusion zones and thus, different alloy families on both sides. Especially with ternary alloys, interesting selective diffusion processes and unexpected repulsion effects were observed. The presentation will provide an overview of the gradient materials with a focus on the functional properties of single-phase alloy families derived from them.
Due to their favorable mechanical and anti-corrosion properties, medium entropy alloys (MEA) are of high academic and industrial interest as novel materials for engineering and catalytic applications. Previous studies on general corrosion behavior indicate high current densities at high anodic potentials for MEAs. Further investigations of the underlying transpassive dissolution and local corrosion behavior remain scarce.
To understand the passivation behavior of MEAs CrCoNi and FeCrNi at high anodic potentials, the mechanisms of transpassive dissolution and the oxygen evolution reaction were investigated in this project. Scanning electrochemical microscopy (SECM) was applied in the interrogative mode for the detection of evolving metal species and oxygen. By means of ICP-MS analysis, dissolved metal species were quantified to provide a fundamental understanding on the transpassive dissolution. As the oxygen evolution reaction (OER) may contribute a large percentile to the observed current at high anodic potentials, SECM measurements were employed to analyze the onset of the OER. Potentiodynamic, potentiostatic and chronoamperometric techniques as well as different electrolytes were used to induce precisely controlled corrosion loads during the SECM experiments and for the ICP-MS analysis. Macroscopic corrosion properties of the alloys, electrical and chemical properties of the passive films were studied by means of potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and X-Ray Photoelectron Spectroscopy (XPS), respectively.
Finally, the analysis of the corrosion morphology and the potential of the surface before, during and after passivity breakdown was carried out by means of in-situ atomic force microscopy (AFM) and scanning Kelvin probe force microscopy (SKPFM). The presentation will summarize our results on the interplay of anodic passivation and oxygen evolution of MEAs in aqueous NaCl electrolytes.
The high-throughput synthesis and characterization of potential material combinations plays an important role in accelerating the development of new materials. Diffusion controlled synthesis of gradient alloys is widely used to create phase diagrams, and it is also one of the most effective combinatorial approaches for rapid realization of potential material combinations.
This study focuses on the synthesis and investigation of the quaternary multi-principle-element alloy (MPEA) FeNiCrMn by means of diffusion multiples, the correlation of their microstructural and chemical characterization data with their application relevant properties like local mechanical and corrosion properties. A diffusion system was set up by combining an equimolar ternary alloy (FeNiCr) with a single diffusing metallic component (Mn) with the highest interdiffusion coefficient. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) were used to collect microstructural and compositional information which were correlated to local mechanical properties studied with nanoindentation. Local corrosion properties were investigated by means of Atomic Force Microscopy (AFM) and Scanning Electrochemical Microscopy (SECM). We have observed that a >50 μm deep homogeneous diffusion zone was formed the thickness of which scales with the duration of the thermal treatment. Beyond the Mn-concentration gradient in the FeNiCr matrix, a distinct Cr-rich secondary phase, characterized by high hardness and elastic modulus values appeared. We synthesized MPEAs with selected compositions from the diffusion zone as well as the Cr-rich phase as bulk alloys for electrochemical corrosion studies under different environmental conditions. The presentation will summarize the results of our correlative study on the mechanical properties and corrosion resistance of the quaternary multi-principle-element alloy (MPEA) FeNiCrMn family.
Presentation of the doctoral thesis held at the PhD Colloquium of the Chair of Innovation Management, Freie Universität Berlin. Hydrogen has recently come into political and industrial focus due to its potential to advance the transition to a net-zero economy. Despite this recognized potential, the market ramp-up of hydrogen technologies has not yet been realized at large. Therefore, this thesis attempts to investigate how advances in hydrogen research, innovation, and safety link up to market formation using the Technological Innovation Systems (TIS) and Quality Infrastructure (QI) frameworks. Thereupon, the thesis formulates several recommendations for transitioning to a hydrogen economy.
Im Verbundforschungsprojekt REALight wurden Leichtgranulate aus gemischtem Mauerwerkbruch in einem thermischen Blähverfahren im Pilotmaßstab hergestellt. Im Teilprojekt der BAM stand die Charakterisierung dieser Leichtgranulate und ihre Anwendung in gebundenen Systemen im Vordergrund. Im Rahmen des Abschlussvortrags wurden Ergebnisse zur Entwicklung von Steinergänzungsmörteln sowie Infraleichtbeton vorgestellt.
Multiphoton lithography (MPL) has recently attracted significant research interest as a versatile tool capable of fabricating 2D and 3D micro- and nanoscopic features with high spatial resolution. The integrity of MPL microstructures, or their ability to respond to external stimuli, is of critical importance. Often, the mechanically flexible micro-objects are expected to be capable of shape morphing, bending, or other motion to ensure their functionality. However, achieving the desired properties of MPL-manufactured micro components for a specific application still remains challenging.
In this work, we present new MPL materials based on epoxy-acrylate interpenetrating networks (IPNs). We aim at fabrication 3D microstructures, whose properties can be easily tuned by varying the ratio of the IPN components and fabrication parameters. The studied mixtures consist of polyethylene glycol diacrylate (PEGDA) and cycloaliphatic epoxide functional groups. Consequently, tryarylsylfonium salt and cyclopentanone photoinitiator tailored for MPL were used to ensure cationic and radical polymerization, respectively. The resulting library of 3D microstructures was investigated for their thermal and mechanical properties using highly sensitive space-resolved methods. For the first time, we were able to evaluate the glass transition behavior of 3D MPL microstructures using fast scanning calorimetry. The influence of both IPN composition and fabrication parameters on glass transition temperature and material fragility was demonstrated. AFM force-distance curve and intermodulation methods were used to characterize the micromechanical properties with lateral resolution of the techniques in the range of 1 micron and 4 nm, respectively. The elastic-plastic behavior of the microarchitectures was evaluated and explained in terms of IPN morphology and thermal properties. The fabricated 3D IPN microstructures exhibit higher structural strength and integrity compared to PEGDA. In addition, IPNs exhibit high to full elastic recovery (up to 100%) with bulk modulus in the range of 4 to 6 MPa. This makes IPNs a good base material for modeling microstructures with intricate 3D designs for biomimetics and scaffold engineering.
The effects of composition and MPL microfabrication parameters on the resulting IPN properties give us a better understanding of the underlying mechanisms and microfabrication-structure-property relationships. Moreover, our funding supports the further development of IPN systems as versatile and easily tunable MPL materials.
In der Abschlusspräsentation des ZIM-Kooperationsvorhabens "TeWuFeAl" werden die wichtigsten Ergebnisse zusammengefasst dargestellt. Ziel des Projektes war die Entwicklung einer Prozess- und Werkzeugtechnologie für das ultraschallunterstützte Fräsen von im Kokillenguss hergestellter Eisen- und Titan-Aluminid-Bauteilen. Auf Basis einer eigens entwickelten Werkzeugtechnologie und Prozessführung konnten die Belastungen auf das Werkzeug und die Oberfläche von Bauteilen aus dem schwer zerspanbaren Eisenaluminid bei der frästechnischen Bearbeitung signifikant verringert werden. Die Messung der Prozesskräfte und der thermischen Belastung der Werkzeugschneide ermöglicht die Ermittlung geeigneter Zerspanungsparameter für eine maximale Werkzeuglebensdauer. Die Anwendung des ultraschallunterstützten Fräsens (USAM) wirkt sich vorteilhaft auf den Zerspanprozess aus. Neben einer deutlichen verlängerung der Werkzeuglebensdauer, zeigen sich Vorteile in Bezug auf die topographischen, metallurgischen sowie mechanischen Eigenschaften der erzeugten Oberflächenintegrität. Die durch USAM erzeugte homogene Bauteiloberfläche weist eine reduzierte Defektdichte und verringerte Rauheitskennwerte auf. Besonders vielversprechend sind die Ergebnisse der Messungen der Eigenspannungen im Tiefenprofil der Oberfläche. Die Werkzeugoszillation bewirkt eine, vergleichbar zum Strahlprozess, Verdichtung der Oberfläche was in Druckeigenspannungen resultiert. Diese potenziell vorteilhaften Druckeigenspannungen können maßgeblich zur Risssicherheit hochbelasteter Komponenten und somit zum Leichtbau und Ressourceneffizienz beitragen.
Ultraschallunterstützte Zerspanung mit geometrisch bestimmter Schneide schwer spanbarer Werkstoffe
(2023)
Das hybride Fertigungsverfahren der ultraschallunterstützen Zerspanung wird mit geometrisch unbestimmter Schneide wie bspw. dem Schleifen bereits erfolgreich in der Industrie eingesetzt und verspricht auch unter Verwendung von Werkzeugen mit geometrisch bestimmter Schneide vielversprechende Vorteile gegenüber den konventionellen spanenden Fertigungsverfahren. In den letzten Jahren wurden an der BAM positive Ergebnisse beim ultraschallunterstützten Fräsen (USAM) von schwer spanbaren Werkstoffen wie z.B. Ni-/Co-Legierungen oder Eisenaluminid für den Leichtbau erzielt aber auch die Finishbearbeitung von schweißtechnisch generierten Bauteilen (AM) bspw. aus FeNi36 konnte hinsichtlich erreichbarer Werkzeuglebensdauer sowie Oberflächenintegrität zur Verbesserung der Komponentensicherheit beitragen. Die mittels USAM erzeugten Oberflächen erscheinen homogener und weisen weniger Defekte infolge des Materialabtrags auf, was sich ebenfalls in verringerten Rauheitskennwerten abbildet. Durch die geringere thermo-mechanische Belastung der Bauteiloberfläche sind Eigenschaftsdegradationen zusätzlich reduziert. Besonders großes Zukunftspotenzial besitzt das ultraschallunterstütze Fräsen durch die Erzeugung von erwünschten Druckeigenspannungen bis unter die Bauteiloberfläche, was auf die oszillierende Wirkung der Werkzeugschneide - vergleichbar mit einem Strahlprozess - zurückzuführen ist. Druckeigenspannungen tragen maßgeblich zur Risssicherheit hochbelasteter Komponenten bei wie sie bspw. in Turbinen vorzufinden sind und können somit zum Leichtbau und zur Ressourceneffizienz beitragen.
Der Vortrag beschreibt den Stand der Arbeiten an der BAM, Fachbereich Umweltanalytik zur Entwicklung von Sensoren für die Wasseranalytik. Er stellt die bisherigen Arbeiten da, die ausgehend von ELISAs, zunehmend portable Plattformen wie FPIA und LFIA umfassen. Beas-based Formate werden von mikrotiterplatten-basierten Techniken auf mikrofluidische Lab-on-Chip-Systeme übertragen, die bei geeigneter Miniaturisierung und Automatisierung als Sensorsysteme angesehen werden können. Der Vortrag endet mit einem Blick auf ein laufendes Monitoring-Projekt von anthropogenen Markern in Abwasser und charakterisiert die Treiber, die die Entwicklung von Sensoren für die Wasseranalytik in den letzten Jahren vorantreiben.
Until the 1980s radiography was used to inspect civil structures in case of special demands and showed a much better resolution than other NDT techniques. However, due to safety concerns and cost issues, this method is almost never used anymore. Meanwhile, non-destructive techniques such as ultrasound or
radar have found regular, successful practical application but sometimes suffer from limited resolution and accuracy, imaging artefacts or restrictions in detecting certain features when applied to reinforced or prestressed concrete inspection.
Muon tomography has received much attention recently. Muons are particles generated naturally by cosmic rays in the upper atmosphere and pose no risk to humans. Novel detectors and tomographic imaging algorithms have opened new fields of application, mainly in the nuclear sector, but also in spectacular cases such as the Egyptian pyramids.
As a first step towards practical application in civil engineering and as a proof of concept we used an existing system to image the interior of a reference reinforced 600 kg concrete block. Even with a yet not optimized setup for this kind of investigation, the muon imaging results have been at least of similar quality compared to ultrasonic and radar imaging, potentially even better. Recently, the research was expanded to more realistic testing problems such as the detection of voids in certain structural elements. However, before practical implementation, more robust, mobile, and affordable detectors would be required as well as user-Friendly imaging and simulation software.
This presentation was held at the 14th International Sustainability Transitions Conference 2023 in Utrecht.
Against the backdrop of the sustainability transition of economies worldwide, decarbonizing road traffic is high on the agenda. This has focused the interest of policymakers and automobile manufacturers on sustainable, zero-emission powertrain technologies. Among these technologies, hydrogen fuel cell (FC) vehicles have a positive climate impact, given that their hydrogen is produced from renewable energy. However, FC vehicles have not yet gained significant market shares. Therefore, based on the technological innovation systems (TIS) approach, this study analyzes how FC vehicles are influenced by EVs and internal combustion engine (ICE) vehicles as their context structures. To operationalize the technology relations between our focal FC-TIS and its context structures, we use the sum of international publications, patents filed at the European Patent Office, and international ISO and IEC standards as indicators for each technology. Our results show that the FC-TIS is dominated by its context structures, especially regarding commercially relevant patents and international standards. Therefore, we conclude that the FC-TIS is in its formative life-cycle phase and identify the need for intensified patenting and standardization in relation to the competing EVs and ICE vehicles.
In maritimer Exposition können Zinkbauteile Nutzungsdauern von 50 Jahren erreichen. Dabei werden Expositionen mit Spritzwasserbelastung durch Meerwasser nicht betrachtet. Normative Betrachtungen und Korrosionsprognosen basierend auf Einjahreswerten liefern hier grundlegend falsche Ergebnisse, da sie eine signifikant höhere Belastung der Atmosphäre mit SO2 voraussetzen.
Ellipsometry is a very powerful tool used for accurate material investigation in a wide wavelength range. It is a non-destructive and fast method. Imaging ellipsometry as a combination of optical microscopy and ellipsometry enables spatially resolved measurements when determining the layer thickness and dielectric properties of thin layers. It is known for its high polarisation sensitivity and high contrast for the surface structures. In this contribution we show the application of the imaging ellipsometry for detection of defects in energy materials and quality validation of possible reference materials for nano-electronics.
Defects in wide bandgap semiconductors, in homoepitaxial SiC and heteroepitaxial GaN layers on transparent SiC substrates, can be successfully detected and classified by means of imaging ellipsometry. Correlation of imaging ellipsometry results with results from complementary techniques such as white light interference microscopy as well as atomic force microscopy contribute to understanding of surface topography and defect formation mechanisms. We discuss the potential of different methods for analysing ellipsometric map data for monitoring the defect densities.
Electric properties of materials at the nanoscale can be investigated by means of scanning probe microscopy methods such as scanning microwave microscopy and conductive atomic force microscopy. However, development of new robust and easy-to-use calibration methods and calibration standards is essential to increase the traceability of these methods and allow their broad application in industry. We show how imaging spectroscopic ellipsometry can be used for development and monitoring of processing quality of patterned reference samples based on indium tin oxide (ITO) layer with different thickness and conductivity.
The built infrastructure ages and requires regular inspection and, when in doubt, monitoring. To ensure that older concrete bridges showing signs of deterioration can be used safely, several innovative monitoring tools have been introduced, including but not limited to optical, fiber-optic, or acoustic emission techniques. However, there are gaps in the portfolio. A sensing technique that covers a wide range of damage scenarios and larger volumes, while still being sensitive and specific, would be beneficial.
For about 15 years, research has been conducted on ultrasonic monitoring of concrete structures that goes beyond the traditional ultrasonic pulse velocity test (PV test), mostly using a very sensitive data evaluation technique called coda wave interferometry. At BAM we have developed sensors and instrumentation specifically for this method.
We have instrumented a 70-year-old, severely damaged prestressed concrete bridge in Germany in addition to a commercial monitoring system. We have now collected data for almost 3 years. We can show that we can provide information about the stress distribution in the bridge. We have also been able to confirm that there has been no significant additional damage to the bridge since the installation.
X-rays without X-rays: Can muon tomography provide pictures from within concrete and other objects?
(2024)
Until the 1980s radiography was used to inspect civil structures in case of special demands and showed a much better resolution than other NDT techniques. However, due to safety concerns and cost issues, this method is almost never used anymore. Meanwhile, non-destructive techniques such as ultrasound or
radar have found regular, successful practical application but sometimes suffer from limited resolution and accuracy, imaging artefacts or restrictions in detecting certain features when applied to reinforced or prestressed concrete inspection.
Muon tomography has received much attention recently. Muons are particles generated naturally by cosmic rays in the upper atmosphere and pose no risk to humans. Novel detectors and tomographic imaging algorithms have opened new fields of application, mainly in the nuclear sector, but also in spectacular cases such as the Egyptian pyramids.
As a first step towards practical application in civil engineering and as a proof of concept we used an existing system to image the interior of a reference reinforced 600 kg concrete block. Even with a yet not optimized setup for this kind of investigation, the muon imaging results have been at least of similar quality compared to ultrasonic and radar imaging, potentially even better. Recently, the research was expanded to more realistic testing problems such as the detection of voids in certain structural elements. However, before practical implementation, more robust, mobile, and affordable detectors would be required as well as user-Friendly imaging and simulation software.
The talk also discusses other applications , such as volcanology, mining and geothermal exploration.
Experimental Setup for the Reproducible Generation of Pressure Waves in Free Field Conditions
(2023)
The injuries caused by the primary blast are still poorly understood, especially in the torso region. To generate sufficiently large data sets, shock tubes are often used. However, these have some limitations, such as blockage, use of the exit jet, widening cross-sections, and scaling problems with respect to compressive strength and test objects. Therefore, it is appropriate to conduct experiments under free-field conditions, but tests with real explosives are often associated with long preparation and setup times as well as high safety requirements.
Therefore, this paper presents an experimental setup for the reproducible generation of blast waves under free-field conditions. This experimental setup aims to provide a test environment for a sufficiently large specimen to investigate the behaviour of the shock wave within the specimen, especially at the media interfaces. As an example of application, the influence of the primary explosive effect on protective equipment or on tissue simulants for the investigation of blast injuries can be mentioned. An autoclave is used as a shock wave generator. It has a volume of 0.065 m3 and is filled with a stoichiometric acetylene-oxygen gas mixture. The setup and turnaround time is approximately 30 minutes. The following factors have been selected as target variables for the optimization of the shock wave generator: reproducibility of the pressure wave, use-case-relevant positive phase duration and peak overpressure, a pressure curve characteristic corresponding to that of a military explosive under undisturbed free field conditions, and short setup times of the experimental setup. For this purpose, the experimental setup is presented in this paper. Several series of measurements are presented, showing the characteristics of the generated pressure wave. For the generated pressure wave, the classical pressure curve characteristics can be clearly recognized. A peak pressure of 92 kPa is reached at a distance of 1 m from the opening, and the first positive pressure phase lasts 1.17 ms. Furthermore, the pressure wave propagates in a hemispherical shape. The typical characteristics of the blast wave generated by the SWG have been demonstrated using the military explosive PETN. It is shown that the actual load case corresponds to about 70 g of PETN.
Der Vortrag beschreibt die grundlegenden Voraussetzungen für das Auftreten von Spannungsrisskorrosion an nichtrostenden Stählen und erläutert den Schadensmechanismus bis zum Versagen des Werkstoffs. Abgeleitet von den notwendigen Voraussetzungen für das Auftreten von SpRK werden werkstoff, medien und belastungsabhängige Einflussfaktoren erläutert, die die Beständigkeit der Werkstoffe gegenüber dieser Schädigungsart positiv wie auch negativ verändern. Weiterhin werden historische und aktuelle Schadensfälle präsentiert und Ursachen, Folgen und mögliche Fehlervermeidung disktutiert. Abschließend werden Prüfverfahren zum Nachweis der Empfindlichkeit von nichtrostenden Stählen gegenüber SpRK näher beschrieben.
Additive manufacturing (AM) processes enable the efficient production of advanced constructions. New developments in topology optimization are leading to weight-optimized designs of increasing complexity. Direct energy deposition processes (DED) such as wire and arc-based additive manufacturing are an important method of additive manufacturing. The wire filler metals enable a wide range of materials, while the arc process provides a high deposition rate compared to laser and powder-based processes. Combined with the use of high-strength steels, the thickness of walls or components can be significantly reduced in the context of lightweight construction, which results in significant savings in energy, costs, time and resources. Suitable high-strength steel filler metals are commercially available for DED-arc AM processes. However, guidelines and quantitative knowledge about welding stresses and cold cracking issues during component production and service are lacking. This limits the industrial application considerably. In a joint project of BAM and Chemnitz University of Technology, the main influences and complex interactions of material, production process, design and processing steps on the residual stress level are investigated. The aim is to develop processing recommendations and a cold cracking test for economical processing and stress-related design of high-strength steels with DED-arc. This study focuses on residual stress analysis by neutron diffraction (ND) and X-ray diffraction (XRD) on defined test specimens. The ND analysis were performed at the Paul Scherrer Institute- Villigen, Switzerland (PSI) and the XRD analysis at BAM. The study shows a quantitative and qualitative comparison of the residual stress magnitudes and distribution between the component bulk (ND) and surface (XRD) analyses. The ND analysis reveals that in DED-arc AM walls the residual stresses dominate in the direction of welding and are negligibly small in each case transverse to the direction of welding. The topology of the analyzed residual stresses shows almost identical residual stress maps compared to XRD. In addition, the residual stresses are significantly influenced by the solid phase transformation of the material due to low cooling times and less post heat treatment cycles of following AM layers in the area of the top layer.
H2Safety@BAM
(2023)
Additive manufacturing (AM) processes enable the efficient production of advanced constructions. New developments in topology optimization are leading to weight-optimized designs of increasing complexity. Direct energy deposition processes (DED) such as wire and arc-based additive manufacturing are an important method of additive manufacturing. The wire filler metals enable a wide range of materials, while the arc process provides a high deposition rate compared to laser and powder-based processes. Combined with the use of high-strength steels, the thickness of walls or components can be significantly reduced in the context of lightweight construction, which results in significant savings in energy, costs, time and resources. Suitable high-strength steel filler metals are commercially available for DED-arc AM processes. However, guidelines and quantitative knowledge about welding stresses and cold cracking issues during component production and service are lacking. This limits the industrial application considerably. In a joint project of BAM and Chemnitz University of Technology, the main influences and complex interactions of material, production process, design and processing steps on the residual stress level are investigated. The aim is to develop processing recommendations and a cold cracking test for economical processing and stress-related design of high-strength steels with DED-arc. This study focuses on residual stress analysis by neutron diffraction (ND) and X-ray diffraction (XRD) on defined test specimens. The ND analysis were performed at the Paul Scherrer Institute- Villigen, Switzerland (PSI) and the XRD analysis at BAM. The study shows a quantitative and qualitative comparison of the residual stress magnitudes and distribution between the component bulk (ND) and surface (XRD) analyses. The ND analysis reveals that in DED-arc AM walls the residual stresses dominate in the direction of welding and are negligibly small in each case transverse to the direction of welding. The topology of the analyzed residual stresses shows almost identical residual stress maps compared to XRD. In addition, the residual stresses are significantly influenced by the solid phase transformation of the material due to low cooling times and less post heat treatment cycles of following AM layers in the area of the top layer.
BAM is part of the “Quality Infrastructure Digital” (QI Digital) initiative of the German Federal Ministry for Economic Affairs and Climate Action (BMWK). This initiative aims at coordinating a large cooperation project, “QI Digital” for making German and European quality management systems fit for the digital transformation. It is a fact that the digitization of new products and services is occurring much faster than quality management systems can be accordingly updated. Thus, the digital transformation of quality management is necessary to preserve the competitiveness of the German and European industries that stand for quality and safety in the global market. The Use Case “Reliable Hydrogen Refueling Station” of QI Digital aims at creating new solutions that are transferable to other technical systems and at further developing standards and technical rules as a contribution to technology transfer and innovation.
This lecture describes the history of hydrogen from the first scientific discoveries in the 18th century to the current technological and political developments for the market ramp-up of hydrogen technologies. The European policy framework for safe hydrogen technologies is explained comprehending the European Green Deal, European Climate Law, European Hydrogen Strategy, Clean Hydrogen Partnership, REPowerEU Plan, Renewable Energy Directive and its Delegated Act, Net Zero Industry Act, etc.
This lecture describes the history of hydrogen from the first scientific discoveries in the 18th century to the current technological and political developments for the market ramp-up of hydrogen technologies. The European policy framework for safe hydrogen technologies is explained comprehending the European Green Deal, European Climate Law, European Hydrogen Strategy, Clean Hydrogen Partnership, etc. Safety in hydrogen technologies is governed by international and European regulations and standards. An overview on regulatory bodies, technical committees, regulations, directives, standards, and technical guidelines with special attention on the BAM-GGR 021 is given in this lecture.
This lecture describes the history of hydrogen from the first scientific discoveries in the 18th century to the current technological and political developments for the market ramp-up of hydrogen technologies. The European policy framework for safe hydrogen technologies is explained comprehending the European Green Deal, European Climate Law, European Hydrogen Strategy, Clean Hydrogen Partnership, etc. Safety in hydrogen technologies is governed by international and European regulations and standards. An overview on regulatory bodies, technical committees, regulations, directives, standards, and technical guidelines with special attention on the BAM-GGR 021 is given in this lecture.
Lithium-ion batteries usually consist of numerous individual cells. There is ongoing discussion about enhancing sustainability by considering the replacement of heavily aged or damaged cells. Nevertheless, the planned replacement of individual cells poses significant challenges in ensuring the required reliability and safety of the refurbished device.
Lithium-ion batteries (LIBs) are essential for the electrification of vehicles and play an important role for stationary storage units needed for grid-balancing. Research groups all over the world work on the improvement of LIBs regarding an increase in energy density as well as cycle-life and a decrease in costs. Next to these research topics, a continuously uprising and crucial field is safety features of LIBs, which can be implemented at different levels, such as material, cell, battery and system level.
The abuse/misuse of a LIB can cause an internal release of heat which can trigger a chain of exothermic reactions on cell level. Hence, the cell temperature increases dramatically, causing the so-called thermal runaway (TR), possibly leading to flames and/or explosion of the cell. Moreover, the TR of one cell can initiate the TR of adjacent cells leading to a so-called propagation, possibly, causing the TR of the whole battery. Ideally, easily obtainable key features of a certain cell – such as cathode type, cell format, cell energy and state of charge (SOC) - could allow the prediction of its behaviour under abuse conditions. In the present study, we will discuss the latest result of our safety tests on cell level employing an external heater as TR-trigger. Single cell tests will be analysed regarding different hazardous features during the TR, e.g., cell temperature, occurrence of flames, peak pressure, gas amount and gas composition. Moreover, the possibility of a TR-propagation and the respective propagation speed will be gained from propagation tests utilizing six cells with identical SOC. In total, the study comprises over 200 tests on cell level. The gained data set is analysed in respect to the cell parameters, such as cell format, cell energy, SOC and the cathode type as well as the atmosphere (air vs. N2) present during the test. A special focus is put on the discussion of general conclusions linking cell parameters to TR-effects and propagation behaviour.
The findings regarding common conclusions between key features and TR-effects can enable a rather facile selection process of cells/batteries for certain applications according to specific safety targets. Moreover, it allows to choose cell-specific safety measures, suitable during operation. In further works, the study will be extended to end-of-first life cells yielding important conclusions regarding crucial safety aspects for the implementation of those cells in 2nd-life application. Generally, the presented results can increase the overall understanding of the TR mechanism supporting the design of advanced measures to enhance the safety on cell level in the future.
Lithium-ion battery (LIB) powered devices, such as laptops, mobile phones and power tools are ubiquitous in our daily lives. Moreover, LIBs are essential for the electrification of vehicles, and play an important role for stationary storage units needed for grid-balancing. The improvement of LIBs, in terms of increasing energy density as well as cycle-life and decreasing costs, is tackled by numerous research groups all over the world. In the last years, research regarding safety aspects has steadily gained more interest. The safety of LIBs can be implemented at different levels, such as material, cell, battery and system level.
The abuse/misuse of an LIB can lead to an internal increase in heat which can trigger a chain of exothermic reactions on cell level. Thus, the cell temperature increases dramatically causing the so-called thermal runaway (TR). This process can lead to flames and/or explosion of the cell. Furthermore, the TR of one cell can initiate the TR of adjacent cells causing the so-called propagation, possibly, leading to the TR of the whole battery.
Herein, we will show the latest result of our safety tests on cell level employing an external heater as TR-trigger. Regarding single cell tests, we will compare different hazardous features during the TR, e.g., cell temperature, occurrence of flames, peak pressure, and toxic gases, depending on the cell format, cell energy and the cathode type. The same cell parameters will be used to discuss the results of the propagation tests. Moreover, the influence of the state of charge (SOC) and the present atmosphere (air vs. N2) as well as the repeatability will be discussed. Overall, the study comprises over 180 tests on cell level.
The findings regarding the TR behaviour can be used to create a hazard-classification scheme of LIBs, e.g., allowing the definition of (cell type specific) conditions for a safe transport. Furthermore, the results can increase the general understanding of the TR mechanism promoting the development of advanced measures to enhance the safety on cell level in the future.
Additive manufacturing (AM) processes enable the efficient production of advanced constructions. New developments in topology optimization are leading to weight-optimized designs of increasing complexity. Direct energy deposition processes (DED) such as wire and arc-based additive manufacturing are an important method of additive manufacturing. The wire filler metals enable a wide range of materials, while the arc process provides a high deposition rate compared to laser and powder-based processes. Combined with the use of high-strength steels, the thickness of walls or components can be significantly reduced in the context of lightweight construction, which results in significant savings in energy, costs, time and resources. Suitable high-strength steel filler metals are commercially available for DED-arc AM processes. However, guidelines and quantitative knowledge about welding stresses and cold cracking issues during component production and service are lacking. This limits the industrial application considerably. In a joint project of BAM and Chemnitz University of Technology, the main influences and complex interactions of material, production process, design and processing steps on the residual stress level are investigated. The aim is to develop processing recommendations and a cold cracking test for economical processing and stress-related design of high-strength steels with DED-arc. This study focuses on residual stress analysis by neutron diffraction (ND) and X-ray diffraction (XRD) on defined test specimens. The ND analysis were performed at the Paul Scherrer Institute- Villigen, Switzerland (PSI) and the XRD analysis at BAM. The study shows a quantitative and qualitative comparison of the residual stress magnitudes and distribution between the component bulk (ND) and surface (XRD) analyses. The ND analysis reveals that in DED-arc AM walls the residual stresses dominate in the direction of welding and are negligibly small in each case transverse to the direction of welding. The topology of the analyzed residual stresses shows almost identical residual stress maps compared to XRD. In addition, the residual stresses are significantly influenced by the solid phase transformation of the material due to low cooling times and less post heat treatment cycles of following AM layers in the area of the top layer.
The overarching goal of this project is to develop a predictive model for efflux-mediated antimicrobial tolerance in bacterial multicellular assemblies. Our central hypostasis is that efflux pump activity causes emergent antibiotic tolerance of multicellular bacterial populations, through the interplay of efflux mediated spatial interactions and efflux-linked persistence. To test this hypothesis, we will use a combination of microscopy, microbial killing assays, computational modelling, and data analysis, integrating information from 3 types of multicellular assembly: colonies, cell-to-cell interactions in a monolayer microfluidic device, and 3D flow chamber biofilms. Building on our preliminary observations, we will experimentally characterize the link between colony structure and spatial patterns of efflux gene expression in strains that differ in their levels of efflux. We will develop a mathematical model to test whether local growth inhibition of neighbors due to effluxing cells, coupled with local environment-dependent regulation of efflux, can account qualitatively for these results. By including persister cell formation in our model we will predict, and measure, the emergent function of antimicrobial tolerance in our colonies. To fully understand how tolerance emerges from the interplay between efflux-mediated spatial interactions and efflux-linked persister cell formation, we need quantitative measurements at the single cell level. To this end, we will use a microfluidic setup with cells growing in a monolayer to qualify in detail the dependence of efflux expression and persister cell formation on nutrient conditions, the correlation between efflux and persister formation, and the spatial range of efflux-mediated neighbour growth inhibition. To predict and quantitatively understand the emergent multicellular function of tolerance, we will perform individual-based modelling of biofilm growth, using as input the parameters measured on the single-cell level with our microfluidics experiments. Our simulations will predict biofilm spatial structure development, patterns of efflux and persister formation and, ultimately, tolerance to antimicrobial challenge. These predictions will be directly tested in flow-cell biofilm experiments. We are currently generating acrAB-tolC knockout-strain, without efflux activity, and a strain with an inducible acrAB-tolC efflux pump. To distinguish the different strains under the microscope, they were labeled with genes encoding for different fluorescent proteins. All strains are currently characterized in terms of growth, minimum inhibitory concentration of different antimicrobial substances, colony morphology, and biofilm formation ability. On the theoretical side, we are currently working on modeling the system at various scales and degree of detail, ranging from coarse-grained continuum models to stochastic, individual-based models. Some exploratory work was doe to test existing software for individual-based modelling that may be adapted for our purpose. Furthermore, we are in the process of developing more coarse-grained models. This work involves some physiological modelling and literature search, focusing on working mechanisms of efflux pumps and kinetic models for import and export of antibiotics.
Stresses in repair welding of high-strength steels Part 2: Heat Control and Stress Optimization
(2023)
In welding of high-strength steels, e.g., for foundations and erection structures of wind energy plants, unacceptable defects can occasionally be found in the weld area, which should be removed by thermal gouging and subsequent re-welding. High shrinkage restraint of repair welds may lead to crack formation and component failure, particularly in interaction with degraded microstructures and mechanical properties due to repair cycles. This study aims for elaboration of recommendations for repair concepts appropriate to the stresses and materials involved to avoid cold cracking, damage and expensive reworking. In part 1 [1] of this study systematic investigations of influences of shrinkage restraint on residual stresses and cold cracking risk during repair welding of two high-strength steels S500MLO for offshore application and S960QL for mobile crane structures were focussed. In this part 2, the microstructure and residual stresses due to gouging and influences of heat control parameters in repair welding are analysed. A clear reduction in residual stress after gouging can be observed, especially for the specimens with restrained transverse shrinkage. Gouging to a depth of approx. 2/3 of the seam height does not lead to a complete relaxation of the observed reaction forces. Particularly for the higher strength steel S960QL, there are pronounced areas influenced by the gouging process in which a degradation of the microstructure and properties should be assumed. Overall, the repair welds show a significant increase in the width of the weld and HAZ compared to the original weld, especially in the case of S960QL/G89. The repair welds show higher welding-induced stresses than the original welds, especially in the areas of the HAZ and the base metal close to the weld seam. This behaviour can be attributed overall to increased restraint conditions due to the remaining root weld or shorter gouge grooves. In good agreement with earlier investigations, the residual stresses transverse to the weld can be significantly reduced by upwardly limited working or interpass temperatures and the reaction stresses resulting from high restraint conditions can be effectively counteracted. The influence of the heat input on the stress formation is low compared to the interpass temperature for both test materials.
Die Thermografie ist trotz ihrer ausgereiften wissenschaftlichen und technologischen Grundlagen ein noch relativ junges Mitglied in der Familie der zerstörungsfreien Prüfverfahren. Sie erschließt sich aufgrund einer Reihe von Vorzügen eine wachsende Anwendungsgemeinde. Für eine weitere Verbreitung insbesondere im industriellen Kontext spielen Normen, Standards und technische Regeln eine wichtige Rolle. In diesem Beitrag wird der aktuelle Stand der Normung in Deutschland vorgestellt. Wir zeigen, welche Normen und technischen Regeln es für die Thermografie in Deutschland und international gibt und wir wagen einen Blick in die Zukunft. Darüber hinaus lebt auch die Normierungsarbeit von der Beteiligung durch interessierte Kreise. Dies können industrielle und akademische Anwender*innen, Hersteller*innen von Geräten, Forschungseinrichtungen oder Dienstleistungsunternehmen sein. Sie können gern Ihre Bedarfe bezüglich Normierungsprojekten mitbringen und/oder direkt an die Autoren senden.
The sustainable and resource-efficient production of wind energy plants requires the use of modern high-strength fine-grain structural steels. This applies to both foundation and erection structures, like mobile or ship cranes. During the assembly of steel structures, unacceptable defects can occasionally be found in the weld area. In most cases, the economical solution would be local thermal gouging of the affected areas and re-welding. Due to the high shrinkage restraint of the joint groove in the overall structure, the superposition of global and local welding-induced stresses may lead to crack formation and component failure, particularly in interaction with the degradation of the microstructure and mechanical properties of high-strength steels during the repair process. However, manufacturers hardly have any information about these issues and there is a lack of recommendations and guidelines to take these safety-relevant aspects into account in adequate repair concepts. The aim of this research is to derive recommendations for repair concepts appropriate to the stresses and materials involved providing a basis for standards and guidelines to avoid cold cracking, damage and expensive reworking especially for high-strength steels. Part 1 of this study involves systematic investigations of influences of shrinkage restraint during repair welding of two high-strength steels S500MLO for offshore application and S960QL for mobile crane structures. The quantification of the shrinkage restraint of repair weld joints was achieved by means of experimental and numerical restraint intensity analysis. In welding experiments with self-restrained slot specimens, restraint intensity and introduction of hydrogen via the welding arc using anti spatter spray were varied systematically to analyse the effect on welding result, residual stresses, and cold cracking. It could be shown that increasing restraint intensities result in significantly higher transverse residual stress levels. In the case of hydrogen introduction S500MLO showed no cold cracking independent of the restraint conditions. However, S960QL was found to be considerably cold cracking sensitive if hydrogen is introduced. With increasing restraint intensity length and number of cold cracks increases significantly. Part 2 [1] of this study is focussed on microstructure and residual stresses due to gouging and stress optimization via adequate heat control parameters in repair welding.
Interaction of L-phenylalanine with Magnetic Metal-Organic Framework: Electrochemical Analysis
(2023)
As the basic units of proteins, the importance of amino acids in organisms is self-evident and therefore detection of the concentration of amino acids is significant in monitoring human health. For example, patients suffering from phenylketonuria should be able to monitor their phenylalanine (PHE) level in a rapid, decentralized, and affordable manner to avoid high levels of PHE in the body which can lead to a profound and irreversible mental disability. Herein, a magnetic and conductive Iron based metal–organic framework (MOF) is prepared using tetrahydroxyquinone and benzene dicarboxylic acid, dual ligands. The uncoordinated carboxyl groups provided the binding sites for PHE. Physicochemical properties of MOF were characterized by XRD, SEM, DLS and FTIR analyses. The effects of different operational parameters: pH (2, 4, 6, 7.2, 8.6, 10, 12), contact time and MOF concentration were optimized for best properties using cyclic voltametric technique. The 10 µl of 1mg/ml MOF (pH 8.6) in deionized water was used as working electrode on screen-printed gold electrode. The presence of new well-defined oxidation and reduction current peak in electrochemical signal of MOF-modified SPGE sensor vs. Ag/AgCl in phosphate buffer solution (pH 1.9) remarks the quantification of PHE. The analytical calibration curve for PHE showed a linear response with concentration in the oxidation and reduction peak current range from 50 to 1000 µM, with a limit of detection (LOD) of 35.16 µM.
Der Vortrag gibt einen Überblick über den Einfluss der Prozessparameter auf die Eigenspannungen sowie die Härte in additiv gefertigten Bauteilen aus hochfestem stahl. Des Weiteren wird dargestellt, wie sich das Bauteildesign und trennende Fertigungsschritte auf die Eigenspannungen der Bauteile auswirken.
Additive manufacturing (AM) processes enable the efficient production of advanced constructions. New developments in topology optimization are leading to weight-optimized designs of increasing complexity. Direct energy deposition processes (DED) such as wire and arc-based additive manufacturing are an important method of additive manufacturing. The wire filler metals enable a wide range of materials, while the arc process provides a high deposition rate compared to laser and powder-based processes. Combined with the use of high-strength steels, the thickness of walls or components can be significantly reduced in the context of lightweight construction, which results in significant savings in energy, costs, time and resources. Suitable high-strength steel filler metals are commercially available for DED-arc AM processes. However, guidelines and quantitative knowledge about welding stresses and cold cracking issues during component production and service are lacking. This limits the industrial application considerably. In a joint project of BAM and Chemnitz University of Technology, the main influences and complex interactions of material, production process, design and processing steps on the residual stress level are investigated. The aim is to develop processing recommendations and a cold cracking test for economical processing and stress-related design of high-strength steels with DED-arc. This study focuses on residual stress analysis by neutron diffraction (ND) and X-ray diffraction (XRD) on defined test specimens. The ND analysis were performed at the Paul Scherrer Institute- Villigen, Switzerland (PSI) and the XRD analysis at BAM. The study shows a quantitative and qualitative comparison of the residual stress magnitudes and distribution between the component bulk (ND) and surface (XRD) analyses. The ND analysis reveals that in DED-arc AM walls the residual stresses dominate in the direction of welding and are negligibly small in each case transverse to the direction of welding. The topology of the analyzed residual stresses shows almost identical residual stress maps compared to XRD. In addition, the residual stresses are significantly influenced by the solid phase transformation of the material due to low cooling times and less post heat treatment cycles of following AM layers in the area of the top layer.
Die Nutzung von Sensortechnologien, insbesondere im Bereich der Gasdetektion mit einem Schwerpunkt auf Wasserstoff, spielt eine entscheidende Rolle in verschiedenen Anwendungsbereichen der Wasserstofftechnologie. Sicherheitsüberwachung, Leckdetektion und Prozesskontrolle gehören zu den prominenten Anwendungsgebieten dieser Sensortechnologien. Ein zentrales Ziel ist die Erkennung von freigesetztem Wasserstoff sowie die genaue Bestimmung des Wasserstoff-Luftverhältnisses mithilfe von Gassensoren. Dies ist von entscheidender Bedeutung, um potenzielle Gefahren frühzeitig zu erkennen und angemessene Maßnahmen zu ergreifen.
Ein weiterer Schwerpunkt dieses Beitrags liegt auf der Analytik und der Verwendung zertifizierter Referenzmaterialien in Verbindung mit Metrologie für die Wasserstoffspeicherung. Dies gewährleistet eine präzise und zuverlässige Charakterisierung von Wasserstoff und unterstützt die Entwicklung sicherer Speichertechnologien. Im Rahmen des Euramet-Vorhabens Metrology for Advanced Hydrogen Storage Solutions (MefHySto) wird eine Kurzvorstellung präsentiert.
Der Vortrag stellt zwei zerstörungsfreie Prüfverfahren zum strukturellen Zustandsüberwachung (Structural Health Monitoring, SHM) für Wasserstofftechnologien vor. Insbesondere die Fehlstellenerkennung mittels geführter Ultraschallwellen spielt eine bedeutende Rolle bei der Lebensdauerüberwachung von Wasserstoffspeichern. Ein weiterer Aspekt ist die Anwendung faseroptischer Sensorik zur Schadensfrüherkennung von Wasserstoffspeichern. Diese zerstörungsfreien Prüfverfahren ermöglichen eine präzise und frühzeitige Identifizierung von Schäden, was die Sicherheit und Effizienz von Wasserstoffspeichersystemen entscheidend verbessert.
The success of this energy transition and the efficient utilization of green hydrogen as a pristine energy carrier hinge upon the cultivation of hydrogen readiness, swift market expansion, and the establishment of crucial value chains within national and European contexts. Paramount to these objectives are reliable quality and safety standards, essential for ensuring supply safety, environmental compatibility, and instilling confidence in these technologies.
In the realm of safety management systems, gas sensors emerge as vital components for detecting hydrogen. This presentation delves into the imperative role of hydrogen systems, emphasizing their capability to monitor and control operations, issue warnings, signal hazardous conditions, and sound alarms. It explores the intricate landscape of functional safety considerations and addresses the challenges associated with measurement uncertainty in sensor testing.
A diverse array of sensors catering to hydrogen, pressure, temperature, and flow are available, each contributing significantly to the safety and efficiency of hydrogen technologies. Applications are envisaged to adhere meticulously to quality infrastructural regulations, codes, and standards, ensuring seamless integration and operation within the broader hydrogen ecosystem.
This discussion underscores the ubiquitous presence of sensor systems across various fields within hydrogen technologies, illustrating their multifaceted contributions to safety, reliability, and overall success in realizing the transformative potential of green hydrogen.
The success of this energy transition and the efficient utilization of green hydrogen as a pristine energy carrier hinge upon the cultivation of hydrogen readiness, swift market expansion, and the establishment of crucial value chains within national and European contexts. Paramount to these objectives are reliable quality and safety standards, essential for ensuring supply safety, environmental compatibility, and instilling confidence in these technologies.
In the realm of safety management systems, gas sensors emerge as vital components for detecting hydrogen. This presentation delves into the imperative role of hydrogen systems, emphasizing their capability to monitor and control operations, issue warnings, signal hazardous conditions, and sound alarms. It explores the intricate landscape of functional safety considerations and addresses the challenges associated with measurement uncertainty in sensor testing.
A diverse array of sensors catering to hydrogen, pressure, temperature, and flow are available, each contributing significantly to the safety and efficiency of hydrogen technologies. Applications are envisaged to adhere meticulously to quality infrastructural regulations, codes, and standards, ensuring seamless integration and operation within the broader hydrogen ecosystem.
This discussion underscores the ubiquitous presence of sensor systems across various fields within hydrogen technologies, illustrating their multifaceted contributions to safety, reliability, and overall success in realizing the transformative potential of green hydrogen.
Additive Fertigungsverfahren wie das Wire Arc Additive Manufacturing (WAAM) ermöglichen die effiziente Fertigung von gewichtsoptimierten endkonturnahen Strukturen in modernen Stahlkonstruktionen. Ihre Effizienz kann weiter durch die Verwendung von hochfesten Stählen gesteigert werden. Dies erlaubt eine signifikante Einsparung von Kosten, Zeit und Ressourcen. Entsprechende Schweißzusatzwerkstoffe für Lichtbogenschweißverfahren sind kommerziell verfügbar. Fehlende Richtlinien und fehlende quantitative Kenntnisse über die schweißtechnische Beanspruchung während der Fertigung und im Betrieb limitieren den industriellen Einsatz stark. Daher werden in einem aktuellen Vorhaben (IGF-Nr. 21162 BG) der BAM und TU Chemnitz die wesentlichen Einflüsse und komplexen Interaktionen durch Werkstoff, Fertigungsprozess, Konstruktion und trennende Fertigungsschritte auf den Beanspruchungszustand untersucht. Der vorliegende Beitrag fokussiert hierfür die Auswirkungen trennender Fertigungsschritte auf Verzug und Eigenspannungen definierter WAAM-Prüfkörper. Die Eigenspannungsanalyse erfolgt mittels Röntgenbeugung. Die große Anzahl an Ergebnissen von zuvor untersuchten Referenzproben, die mit einem speziellen WAAM-Massivdraht (Streckgrenze >820 MPa) bei unterschiedlicher Wärmeführung und Geometrie vollautomatisiert geschweißt wurden, lässt eine Korrelation der Messdaten zu. Hierzu erfolgt die Analyse des Ausgangszustandes und abschließend des Zustandes nach trennender Bearbeitung, welche begleitend mittels digitaler Bildkorrelation hinsichtlich des Verzuges untersucht wurden. So ist zu beobachten, dass die Geometrie deutlichen Einfluss auf Relaxation und Umlagerung der Eigenspannungen hat und damit die Risssicherheit positiv beeinflussen kann.
Deconvoluting the impact of early-life abuse conditions on the degradation of lithium-ion cells
(2023)
The successful repurposing of degraded lithium-ion (Li-ion) batteries in second-life applications is a vital step towards achieving a circular economy. While reusing aged Li-cells is a promising way of mitigating their overall environmental footprint, it is crucial to anticipate their future safety and performance characteristics . Unfortunately, predicting these properties is a cumbersome task, essentially caused by limited knowledge of the interference of different degradation modes in the cells’ first life.
To still enable estimating of these parameters from a current state, the present study systematically investigates the impacts of abusive conditions in an early phase of the cells’ life on their subsequent degradation behavior. For this purpose, individual Li-cells are initially stressed by different measures such as overcharging, deep-discharging, plating, and deliberate combinations of the aforementioned methods. Electrochemical performance indicators are monitored during subsequent cycling of the cells which provides insights into the interdependencies of different degradation modes induced by specific stress conditions. In this manner, it is clarified whether or not the total degradation can be determined by a convolution or a superposition of individual deterioration effects and, thus, be described as a multidimensional state function.
This knowledge will finally contribute to a better understanding of the performance and safety behavior of degraded Li-ion batteries which can help to successfully implement them into second-life applications.
Um den Aspekt der Strategie zur Fehlervermeidung und Schadenprävention in Wasserstofftechnologien zu integrieren, ist es entscheidend, proaktiv auf potenzielle Schwachstellen in den Systemen und Prozessen zu achten. Dies beinhaltet die Implementierung von präventiven Maßnahmen als Elemente des Sicherheitsmanagements, um mögliche Fehlerquellen zu identifizieren und zu eliminieren. Darüber hinaus sollten Schulungen gezielt auf die Vermeidung von Fehlern und die sichere Anwendung von Wasserstofftechnologien ausgerichtet sein. Eine durchdachte Strategie zur Fehlervermeidung trägt wesentlich dazu bei, Unfälle zu verhindern und die Gesamtsicherheit bei der Nutzung von Wasserstoff zu erhöhen.