BAM-Publica - Publikationsserver der Bundesanstalt für Materialforschung und -prüfung
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Bericht zum Fortschritt des laufenden Projekts: "Hybrider Einsatz von LTT-Schweißzusätzen zur Schwingfestigkeitsverbesserung hochfester Stahlbauteile"
No full textDieses Dokument fasst den Projektfortschritt des BAM-Projektes "Hybrider Einsatz von LTT-Schweißzusätzen zur Schwingfestigkeitsverbesserung hochfester Stahlbauteile" im Rahmen des Sitzung des DVS Fachausschuss FA09 - Konstruktion und Festigkeit für die Projektquartale Q4 2024 und Q1 2025 zusammen und stellt die wichtigsten Ergebnisse in Kurzform vor
Testing of vacuum insulation panels for liquefied hydrogen storage tanks
No full textFor the future use of liquefied hydrogen (LH2) as a green energy carrier, new concepts for storage tanks and in particular their insulation are necessary. The methodology applied in current LH2 tanks has some disadvantages while manufacturing and operation of large tanks that may be required in the future. While liquefied natural gas tanks exist in the necessary capacities, they are incompatible with LH2 due to its significantly lower storage temperature. In this paper, the possibility of using vacuum insulation panels (VIPs) as an alternative to the conventional double walled, powder filled vacuum insulation is presented. The two systems are introduced and compared on a conceptual level with a focus on the loss of vacuum failure mode. Furthermore, a test rig that enables the testing and quantification of thermal properties of VIP based insulations in ordinary and loss of vacuum conditions is presented. The test rig is a boil-off calorimeter using liquefied nitrogen and features a square cold surface with a side length of 3 m. An overview over the planned testing and its goals is given
Lignocellulosic biomass and its main structural polymers as sustainable materials for (bio)sensing applications
No full text(Bio)sensors are integral to various aspects of daily life, contributing to safety, monitoring, and awareness. In modern sensor devices, polymers play an important role, with increasing interest in bio-based materials. Biopolymers, unlike their synthetic counterparts, are abundant in nature and exhibit interesting functional properties that make them highly suitable as biomaterials for sensor technologies. Enhancing sensor performance to achieve a rapid response to stimuli is a key objective in sensor development. Lignocellulosic biomass (LCB) from plants holds promise in meeting such requirements due to its high surface area, tunable surface characteristics (including diverse pore sizes and morphologies), flexibility, printability, low density, and favorable physicochemical and thermal properties. Growing research in recent decades has focused on lignocellulosic composite materials due to their functional and environmentally friendly attributes. This review focuses on the valorization of lignocellulosic biomass and its three main biopolymer constituents (cellulose, hemicellulose, and lignin) for the development of electrochemical (bio)sensors. It also explores the macromolecular structure, sources, and inherent properties of LCB, with emphasis on the three main biopolymers and their applications in sensor technologies. Recent advances in the use of LCB and its structural biopolymers as materials for (bio)sensing applications are described and reviewed. The challenges associated with using these biomaterials in electroanalytical applications are also discussed, along with the exploration of their future potential for developing high-performance sensing technologies
Repeatable testing of a cryogenic storage tank with variable insulation material in fire like conditions
No full textFor decarbonizing the energy industry and transport, cryogenic energy carriers have great potential. The storage takes place in tanks with thermal super-insulations, which are in application for decades, but there is only limited knowledge about its behaviour in a fire scenario. This represents a major incident that may generate extraordinary loads on the tank and its insulation system, and that eventually lead to a sudden tank failure. This paper presents a test rig called the Cryogenic High Temperature Thermal Vacuum Chamber (CHTTVC), which can be used to test typical thermal superinsulation’s under cryogenic and fire-like conditions in parallel. The test method makes it possible to measure the heat flow through the thermal superinsulation over time and to investigate the degradation behaviour of the insulation within a test. In the paper results from the first tests are presented
Common Strategies for Advancing the Digital Transformation in Materials Science
No full textMaterials science and engineering is inherently interdisciplinary, bridging the natural sciences and engineering domains. This diversity is reflected in its digitalisation efforts, where subdomains often define distinct data structures, taxonomies, and terminologies. As a result, semantic ambiguities and fragmented research data management remain major obstacles to data integration across the field.
Recent advances in AI underscore the role of data as a strategic resource for innovation. However, the effectiveness of these methods depends on the availability, completeness, and quality of data. Well-structured and semantically annotated materials and process data that is processed and stored using semantic technologies, for example, can enable breakthroughs, particularly at the interface of processing, structure, properties, and performance. A systematic, coordinated approach grounded in the FAIR guiding principles and lifecycle-oriented data management is therefore essential.
The German MaterialDigital Initiative, funded by the Federal Ministry of Education and Research, exemplifies such a collaborative framework. It brings together diverse project consortia, fostering community-driven consensus through exchange forums like the Ontology Playground, and supporting harmonized solutions for semantic interoperability.
By strengthening data culture and semantic infrastructure, collaborative digitalisation initiatives offer a scalable path to accelerated materials development and reproducible scientific progress paving the way for more efficient, data-driven innovation in materials science and engineering
Pinning-dominated strengthening in high-entropy superalloys
No full textHierarchical microstructural design of high-entropy superalloys offers novel strengthening pathways beyond classical superalloys. Here we assess the strength of isolated γ’ precipitates with and without an additional internal γ nanophase. The results show that nano-precipitation within the γ’ phase leads to a marked statistical reduction of the dislocation-nucleation limited yield strength. In concert with disorder-driven chemical weakening of the γ’ phase, these findings indicate that bulk strengthening due to hierarchical microstructural design in high entropy superalloys must primarily be pinning dominated
GlasDigital: Data-driven workflow for accelerated glass development
No full textGlasses stand out by their wide and continuously tunable chemical composition and large variety of unique shaping techniques making them a key component of modern high technologies. Glass development, however, is still often too cost-, time- and energy-intensive. The use of robotic melting systems embedded in an ontology-based digital infrastructure might overcome these problems. As part of the German research initiative MaterialDigital [1], the joint project GlasDigital took first steps in this direction combining all main components required for accelerated data driven glass development. For this purpose, a robotic high throughput glass melting system was equipped with inline sensors for process monitoring, machine learning (ML)-based adaptive algorithms for process monitoring and optimization, novel tools for high throughput glass analysis and ML-based algorithms for glass design, including data mining as well as property and process modelling. The talk gives an overview how these tools are interconnected and illustrates their usability
Theoretical and experimental development of negative thermal expansion material ZrV2O7
No full textZirconium vanadate (ZrV2O7) is a well-known negative thermal expansion (NTE) material which stands out for its remarkable isotropic unit cell contraction over a broad temperature range (130°C < T < 800°C). This enables the fabrication of composites where the overall expansion coefficient can be tailored to a specific negative, positive, or neutral value. Consequently, such composite materials are attractive for many device applications because they can compensate for damage caused by thermal expansion. They are relevant to optical systems, electronic and biomedical applications.
In this study, we implement ab-initio-based vibrational computations with partially treated anharmonicity (quasi-harmonic approximation (QHA), temperature-dependent effective harmonic potentials (TDEP)[5]) in combination with experimental methods to follow and rationalize the negative thermal expansion in this material, including the influence of the local structure disorder, microstructure, and defects. In analytical techniques that can provide structural information such as pair distribution function analysis (PDF), X-ray diffraction (XRD), and Extended X-ray Absorption Fine Structure (EXAFS), molecules and atoms are fit geometrically without consideration of atom interactions. Therefore, in combination with these methods, we also consider potential energy surfaces and conclude what structures are likely to form energetically in the full NTE temperature range, in addition to fitting experimental data geometrically. We also optimise experimentally fitted structures to their lowest energy configurations and re-generate comparative data to observe what differences would be visible experimentally
More than 25 years of ink analysis non-destructive testing of black writing materials
No full textWriting inks can be divided into soluble inks and dispersion inks. Soluble inks are based on plant or insect dyes forming a water solution. In the early European Middle Ages brown plant inks were usually produced from the blackthorn bark and wine. In contrast to these soluble brown inks, one of the oldest black writing materials was produced by mixing soot with gum arabic or animal glue dissolved in a small amount of water. From Pliny’s detailed account of the manufacture of various black carbon inks, we learn that producing pure soot of high quality was not an easy task in Antiquity. Iron gall inks are a borderline case between these two groups. They are produced from four basic ingredients: gallic acid, an iron-containing component, gum arabic as a binding media, and an aqueous medium such as wine, beer, or vinegar. By mixing gallic acid with soluble iron ions, a water-soluble ferrous gallate complex is formed. Exposure to oxygen leads to the formation of insoluble black ferric gallate pigment. Due to the variety of recipes and the natural origin of raw materials, there is a wide range of different components and impurities in writing inks. The Bundesanstalt für Materialforschung und -prüfung (BAM) together with the Centre for the Study of Manuscript Cultures in Hamburg (CSMC) has developed a protocol for ink analysis. It consists of a primary screening to determine the type of the ink and a subsequent in-depth analysis using several spectroscopic techniques (X-ray fluorescence analysis and vibrational spectroscopy). This contribution presents a qualitative and quantitative analysis of historical writing inks to characterize distinguishable inks in manuscripts, to determine the origin of manuscripts, and to assign unknown fragments to time and place
Two heads are better than one: Aluminum trihydroxide / phosphorous flame retardant combination in natural waste fiber biocomposites
No full textFuture polymeric materials that replace fossil fuel-based engineering plastics demand the use of renewable sources as well as the implementation of key properties such as flame retardancy, processing, and mechanical properties. This study focuses on the combination of aluminum trihydroxide (ATH) and phosphorus-based flame retardants in compositable thermoplastic starch reinforced with sustainable multifunctional leather waste fibers. The flame retardants engender different flame-retardant modes of action, improving overall performance when combined. The partial substitution of ATH with phosphorous flame retardant allowed a reduction in flame retardant loading. Materials with 90 phr of ATH reached a limiting oxygen index of 31.5 vol.-% and a UL-94 rating of V-1, whereas the combination of 73 phr ATH and 7 phr of diphenyl ocytyl phosphate achieved a V-0 rating and a slightly reduced peak of heat release rate. This study demonstrates the potential of multicomponent systems implementing waste fiber–reinforced biocomposites