TY - CONF A1 - Agudo Jácome, Leonardo A1 - Suárez Ocaño, Patricia T1 - The Al4-xZr5(Ox-y) Trojan horse in the AlMo0.5NbTiTa0.5Zr refractory high entropy superalloy N2 - Unlike conventional alloys, which typically consist of one main element, high-entropy alloys (HEAs) contain five or more principal elements, which broaden chemical complexity and with it a realm of synergistic mechanisms. The AlMo0.5NbTa0.5TiZr HEA initiated a subclass of Al-containing refractory (r)HEAs that has recently drawn attention [2]. The alloy has a superalloy-resembling B2/bcc nanostructure, which inspired its name refractory high entropy superalloy (RSA). With high-temperature (HT) compressive strengths beyond conventional Ni-based superalloys, this nanostructure could be used for improved HT structural applications. However, in the application-relevant HT regime the Al-Zr-rich B2 phase decomposes to form a hexagonal Al-Zr-based intermetallic (Al4-xZr5; x: 0..1) [3,4]. This work explores the fascinating yet fatal micromechanisms associated to this phase transformation, in the context of creep, annealing and oxidation experiments performed between 800 and 1200 °C. The material was produced by arc-melting and heat treatment in argon, which lead to grain boundaries decorated with up to 7%. Interrupted constant-load creep tests were performed under vacuum (at 10-4 Pa), at 900–1100 °C with external tensile stresses of 30–120 MPa. Oxidation experiments were separately conducted for 24 hours at 800 and 1000 °C in both dry (21% O2 + 79% N2) and humid (8% O2 + 74% N2 + 18% H2O) air. After the experiments, the samples were characterized by X-ray diffraction, scanning electron microscopy and transmission electron microscopy to reveal degradation mechanisms. Crystallographic texture, orientation relationships and stabilization of an oxygen-containing iso structure (Al4-xZr5(Ox-y); y: 0..x) of the Al-Zr-rich intermetallic are found and discussed. T2 - BCC Superalloy Network Opening Workshop CY - Reutte, Austria DA - 08.02.2024 KW - High entropy alloy KW - Superalloy KW - Degradation KW - Electron microscopy KW - Microstructure PY - 2024 AN - OPUS4-59833 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weber, Simone A1 - Altmann, Korinna A1 - Wohlleben, W. T1 - Influence of the pH Value to the Degradation of Ester-Based Thermoplastic Polyurethanes N2 - Microplastics are solid polymeric particles with a size of 1-1000 μm (ISO/TR21960:2020), which can be emitted from mismanaged waste into the environment, where microplastic is now ubiquitous. What happens to the microplastics after ending up in the environment, which risks entail and what effects it has are not sufficiently clarified up to now. The most certain issue is that the plastic particles in the environment are exposed to natural ageing, are fragmenting and degrading, such that the potential risk to ecosystems and humans is increasing due to the formation of smaller and smaller particles, potentially even including nanoplastics, if these are ingested before their further degradation. Therefore, and in view of a possible registration of polymers under REACH in the future, it is necessary to investigate the degradation of thermoplastic polyurethanes (TPU) regarding hydrolysis stability to evaluate possible risks and effects to the environment. In the present studies, one thermoplastic polyurethane – with and without hydrolysis stabilizer – is exposed to different pH buffers at 50°C for 14 days to investigate hydrolysis depending to different pH values (acid, alkali and neutral) based on OECD guideline TG111. The hydrolysis behavior of the TPUs is characterized by surface sensitive techniques and on bulk properties. First degradation effects can be detected by SEC. Hydrolysis, especially under acidic and basic conditions, leads to chain scissions to lower molecular masses. Furthermore, the degradation products which indicate the structure of the bulk material were detected by thermo-analytical methods like TGA-FTIR for the small degradation products and the thermo extraction/desorption-gaschromatography/mass spectrometry (TED-GC/MS) for bigger degradation products. Acidic and basic hydrolysis shows the same degradation behavior which is caused by a preferred scission of the ester and urethane functionalities. Surface-sensitive techniques such as XPS demonstrate less carboxylic acid formation at acidic than at alkaline pH value in the TPU without stabilator, where as the TPU with stabilator ages to the same extent in both pH ranges. Altogether, the hydrolysis of TPUs – independently of added stabilizer or not – in acid and alkali environment is accelerated compared to the neutral hydrolysis. T2 - SETAC CY - Dubin, Ireland DA - 30.04.2023 KW - Degradation KW - Thermoplastic Polyurethane KW - Microplastic KW - Polymer Hydrolysis KW - Polymer 3R KW - REACH PY - 2023 AN - OPUS4-58906 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Meurer, Maren A1 - Wiesner, Yosri A1 - Geburtig, Anja A1 - Waniek, Tassilo A1 - Altmann, Korinna T1 - Is olypropylene relevant for microplastic analytics? N2 - Nowadays, in every terrestrial and aquatic ecosystem, even in the remotest areas, small residues of plastics, the so called microplastic (MP) can be found. MPs are particles with a size of 1-1000 µm (ISO/TR 21960:2020), mainly containing synthetic polymers like polyethylene (PE), polypropylene (PP), polystyrene (PS) or polyethylene terephthalate (PET). Even styrene-butadiene rubber (SBR) as an indication for tire wear is included due to similar particle formation. To understand the MPs consequences to the environment, it is of high priority to capture its extent of contamination. It is surprising that in the analysis of polymer masses in environmental samples, PE, PS and SBR are often detected, but only small amounts of PP, although this is the second most commonly produced standard plastic and many MP particles originate from carelessly disposed packaging materials. This presentation provides hypotheses about the reasons of rare PP identification and mass quantification in environmental samples. Different investigations of pristine PP and representative environmental samples, including the pre-treatment by Accelerated Solvent Extraction (ASE) or with density separation followed by the thermal extraction / desorption gas chromatography-mass spectrometry (TED-GC/MS) are presented. The results are discussed according to the material properties and a possible degradation mechanism under different weathering conditions which indicate less stability under relevant storage conditions. T2 - Society of Environmental Toxicology and Chemistry CY - Dublin, Ireland DA - 30.04.2023 KW - Sample preparation KW - Polypropylene KW - Microplastic KW - Degradation PY - 2023 AN - OPUS4-57474 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wiesner, Yosri A1 - Eisentraut, Paul A1 - Altmann, Korinna T1 - Erfassung von Degradationsprodukten und Additiven sowie temperaturspezifische Pyrolyseprodukte mittels TED-GC/MS N2 - Im der Präsentation werden, neben der Möglichkeit der Mikroplastikquantifizierung, auf weitere Anwendungsfelder der Methode TED-GC/MS eigegangen. Dies beinhaltet die Erfassung von Degradationsprodukten UV/O2 geschädigter Polymere und die Detektion von Additiven. Die Optimierung der Methode betreffend Messzeit und materialspezifischer Messanforderung sind ebenfalls Gegenstand. T2 - Kolloquium Massenspektrometrie von Polymeren CY - Berlin, Germany DA - 09.05.2023 KW - TED-GC/MS KW - Polymere KW - Degradation KW - Additive PY - 2023 AN - OPUS4-57480 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - John, Sebastian A1 - Duffner, Eric A1 - Mair, Georg T1 - Degradation and damage analysis of composite pressure vessels via experimental modal analysis T2 - NOVEM 2023 Noise and Vibration: Emerging Methods N2 - For mobile gas storage systems, the application of type IV pressure vessels is state of the art. Type IV tanks consist of an inner polymer liner fully wrapped with fibre-reinforced plastic (FRP). Because of the complex fabric of the FRP as well as a difficulty estimable interaction behaviour between the single components under load, there are still no satisfying non-destructive testing methods to assess the current state of failure nor to estimate the level of degradation accurately and economically. At BAM division 3.5, analysing the ageing process of mobile composite pressure vessels is a major task to ensure safe usage over the whole lifetime. In this context, key aspects of our ongoing research activities are the invention of new test procedures and the development of accurate lifetime prediction models. In order to determine the level of degradation or damage, one meaningful non-destructive approach is to analyse the structural dynamic behaviour via an experimental modal analysis (EMA). Over the last few years, different types and sizes of composite pressure vessels have been tested in several research projects. The presented paper gives an insight into how to extract and interpret modal parameters and how to fit them to the results of residual strength tests. T2 - NOVEM Conference 2023 CY - Auckland, New Zealand DA - 09.01.2023 KW - Composite material KW - Pressure vessel KW - Degradation KW - Modal analysis PY - 2023 SP - 57-1 EP - 57-6 AN - OPUS4-58062 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - John, Sebastian A1 - Duffner, Eric A1 - Mair, Georg T1 - Degradation and damage analysis of composite pressure vessels via experimental modal analysis N2 - For mobile gas storage systems, the application of type IV pressure vessels is state of the art. Type IV tanks consist of an inner polymer liner fully wrapped with fibre-reinforced plastic (FRP). Because of the complex fabric of the FRP as well as a difficulty estimable interaction behaviour between the single components under load, there are still no satisfying non-destructive testing methods to assess the current state of failure nor to estimate the level of degradation accurately and economically. At BAM division 3.5, analysing the ageing process of mobile composite pressure vessels is a major task to ensure safe usage over the whole lifetime. In this context, key aspects of our ongoing research activities are the invention of new test procedures and the development of accurate lifetime prediction models. In order to determine the level of degradation or damage, one meaningful non-destructive approach is to analyse the structural dynamic behaviour via an experimental modal analysis (EMA). Over the last few years, different types and sizes of composite pressure vessels have been tested in several research projects. The presented paper gives an insight into how to extract and interpret modal parameters and how to fit them to the results of residual strength tests. T2 - NOVEM 2023 CY - Auckland, New Zealand DA - 09.01.2023 KW - Pressure vessel KW - Composite KW - Modal analysis KW - Degradation PY - 2023 AN - OPUS4-58063 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wachtendorf, Volker A1 - Barthel, Anne Kathrin A1 - Meyer-Plath, Asmus A1 - Sturm, Heinz A1 - Kalbe, Ute A1 - Bandow, Nicole A1 - Krüger, Oliver T1 - Maßgeschneiderte künstliche Bewitterungstests zur Untersuchung der alterungsbedingten Freisetzung von Produkten in die Umwelt N2 - Genormte künstliche Bewitterungstests sind häufig nicht spezifisch für die Anwendungssituation oder das Material. Das macht die Entwicklung spezifischer Tests erforderlich. Für deren Entwicklung müssen Maximalparameter der Anwendungssituation bekannt sein, womit dann der künstliche Test formuliert wird und dessen Bedingungen werden dann solange optimiert, bis die Korrelation der Effekte von natürlichem und künstlichem Test ausreichend ist. Für Untersuchungen der Freisetzung kann der verbleibende Rest in der Probe und/oder die freigesetzte Menge in Luft, Boden, Wasser bestimmt werden. Im ersten Beispiel der Witterungswirkung wurde die Freisetzung von Kohlenstoff-Nanoröhrchen (CNT) aus Polymer-Kompositen untersucht (unter Verwendung von empfindlich-nachweisbarer radioaktiver 14C-Markierung für einzelne CNT-Partikel), in einem zweiten die Freisetzung von anorganischen und organischen Bestandteilen aus elastomeren Bestandteilen von Sportböden (Bahnen und Kunstrasen) in Wasser. T2 - SKZ-Tagung: Bewitterung van Kunststoffen CY - Würzburg, Germany DA - 06.07.2022 KW - Künstliche Bewitterung KW - UV KW - Degradation KW - Freisetzung KW - CNT KW - Carbo-Nanotubes KW - Composite KW - Nano-Partikel KW - 14C-Markierung KW - Sportböden KW - Kunstrasen KW - Grundwasser PY - 2022 AN - OPUS4-55219 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Skrotzki, Birgit T1 - Aging processes in precipitation hardened aluminum alloys N2 - The mechanical strength of wrought high-strength aluminum alloys is essentially based on precipitation hardening, possibly in combination with prior forming, e. g. by stretching. Important parameters for achieving an optimum combination of hardness, strength, ductility, toughness, and further properties such as corrosion resistance are age-hardening temperature and time. During thermal (mechanical) treatment, nucleation and growth of precipitates takes place, leading to the desired degree of hardening. In aluminum alloys, precipitation sequences are usually passed through, i. e. a sequence of metastable precipitates is formed before the stable phase can precipitate. The optimum combination of properties is therefore based on a certain (optimum) microstructure, which can, however, change during the use of a component, since the microstructure is not stable. This happens in particular when the operating temperatures are close to the aging temperature and/or the operating times are sufficiently long. An external mechanical load may accelerate the processes. The presentation gives some examples for this. T2 - Materials Science and Engineering Congress MSE 2022 CY - Darmstadt, Germany DA - 27.9.2022 KW - Aluminium alloy KW - Precipitation hardening KW - Aging KW - Degradation PY - 2022 AN - OPUS4-55877 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Richter, Tim A1 - Rhode, Michael A1 - Nietzke, Jonathan A1 - Mente, Tobias A1 - Mayr, P. A1 - Nitsche, A. T1 - Hydrogen embrittlement and mechanical properties of 9 % Cr P92 steel and P91 weld metal N2 - Martensitic 9 %-Cr steels like P91 and P92 can show an increased susceptibility to delayed hydrogen assisted cracking. The focus of this study was the microstructure and heat treatment effect on the mechanical properties of P92 base material and P91 multi-layer weld metal in both as-welded and post weld heat treated (PWHT) condition. Tensile tests with hydrogen free reference samples and electrochemically hydrogen charged samples were carried out, the mechanical properties were assessed and supported by dedicated fractographic analysis. In addition, hydrogen and microstructure dependent fracture criteria were calculated. All investigated microstructures showed a hydrogen influenced degradation of the mechanical properties compared to the hydrogen free reference samples. In that connection, the as welded martensitic P91 weld metal had the highest degree of degradation in presence of hydrogen. The P91 PWHT weld metal and the P92 base material had comparable properties. From that point of view, a significantly increased risk for hydrogen assisted cold cracking during welding fabrication of P91 weld joints must be considered before any heat treatment is conducted. T2 - IIW Annual Assembly, Meeting of Commission IX-C CY - Tokyo, Japan DA - 21.07.2022 KW - Creep-resistant steel KW - Mechanical properties KW - Hydrogen assisted cracking KW - Weld joint KW - Degradation PY - 2022 AN - OPUS4-55462 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pirskawetz, Stephan A1 - Weise, Frank A1 - Rieffel, Y. A1 - Gorbushina, Anna T1 - Die Schlossbrücke Berlin - Schutz der Göttinnen T2 - N.i.Ke. Schriftenreihe des Netzwerks zur interdisziplinären Kulturguterhaltung in Deutschland N2 - Vielleicht nannten es die Berliner „Puppen putzen“, wenn in den 1880er Jahren die Marmorstatuen auf der Schlossbrücke vor dem Berliner Stadtschloss mit Bürste, Wasser und Seife von Staub, Ruß und Taubendreck befreit wurden. Soviel Pflege wurde diesen Göttinnen aus der griechischen Mythologie nicht immer zuteil. So haben Klima, Luftverschmutzung und der 2. Weltkrieg, wie bei anderen Kunstwerken auch, tiefe Spuren hinterlassen. Der Erhalt dieser zwischen 1847 und 1857 aufgestellten Skulpturen und vieler vergleichbarer Objekte im Stadtbild ist durch die auch heute weiter fortschreitende Schädigung des Marmors gefährdet. In den Jahren 2006 bis 2010 förderte die Deutsche Bundesstiftung Umwelt (DBU) ein Projekt zur „Entwicklung und Überprüfung von Einhausungssystemen zur Reduzierung umweltbedingter Schädigungen von außenexponierten Marmorobjekten mit dem Ziel des langfristigen Erhalts in situ an einem national bedeutenden Objektkomplex, den Schlossbrückenfiguren unter den Linden, Berlin“. Geleitet und restauratorisch betreut wurde das Projekt durch das Landesdenkmalamt (LDA) Berlin. Durch die Abteilung Strukturgeologie und Geodynamik (GZG) der Georg-August Universität Göttinnen wurden die Verwitterungsmechanismen des Marmors untersucht und auf dieser Basis Anforderungen an das Schutzsystem formuliert. Anhand von numerischen Simulationen des Instituts für Bauklimatik der Technischen Universität Dresden (TUD) wurde das bauphysikalische Konzept des Einhausungssystems optimiert. Die konstruktive Gestaltung eines Prototyps und des finalen Entwurfs erfolgte durch das Fachgebiet Konstruktives Entwerfen und Tragwerkslehre der Universität der Künste Berlin. Durch den Fachbereich Baustoffe der BAM erfolgten die Realisierung des Prototyps der Einhausung sowie ein umfangreiches Klimamonitoring an den Skulpturen. Anhand dieses interdisziplinären Projektes und ergänzt durch weitere Messungen wird gezeigt, mit welchen Methoden die für die Degradation von Marmor relevanten Mechanismen untersucht werden können. Die Erkenntnisse aus dem Projekt sind die Grundlage für die Entwicklung nachhaltiger Pflege- und Schutzkonzepte für die kulturhistorisch wertvollen Skulpturen. Nur mit solchen modernen konservatorischen Programmen können die Originalskulpturen im Berliner Stadtraum erlebbar bleiben. T2 - Workshop Kulturerhaltung - Vom Dampfkessel zu Nanomaterialien CY - Berlin, Germany DA - 17.11.2021 KW - Baustoffe KW - Marmor KW - Verwitterung KW - Kulturelles Erbe KW - Wintereinhausungen KW - Klima KW - Zerstörungsfreie Prüfung KW - Building materials KW - Marble KW - Degradation KW - Cultural heritage KW - Winter shelters KW - Climate KW - Nondestructive testing PY - 2021 SN - 2567-1251 VL - 3 SP - 87 EP - 96 PB - Druckerei G. Bohm CY - Berlin AN - OPUS4-54637 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -