TY - JOUR A1 - Nietzke, Jonathan A1 - Konert, Florian A1 - Poka, Konstantin A1 - Merz, Benjamin A1 - Sobol, Oded A1 - Böllinghaus, Thomas T1 - Comparison of hydrogen effects on additively manufactured and conventional austenitic steels N2 - Hydrogen and its derivatives are promising energy carriers for future renewable energy supplies. Austenitic stainless steels, such as AISI 316L, are commonly used in hydrogen transportation systems. While often thought to be resistant to hydrogen embrittlement, studies have shown that 316L is susceptible under certain conditions. As demand for hydrogen applications grows, additive manufacturing (AM) technologies offer design flexibility and customisation benefits. However, data on AM parts behaviour in hydrogen environments is lacking. This study investigates the influence of hydrogen on mechanical properties using slow strain rate testing (SSRT) on conventional AISI 304L, 316L and AM 316L specimens. The results indicate a greater effect of hydrogen on 304L compared to 316L, with AM 316L showing increased susceptibility. However, the ductility of AM 316L remains comparable to conventional 316L due to its initial ductility. The study provides insights into the performance of conventional and AM austenitic stainless steels in gaseous hydrogen environments. KW - Slow strain rate testing KW - Hollow specimen KW - Hydrogen embrittlement KW - Additive manufacturing KW - Austenitic steel PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-615919 DO - https://doi.org/10.1016/j.engfailanal.2024.109042 SN - 1350-6307 VL - 167 SP - 1 PB - Elsevier B.V. AN - OPUS4-61591 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Grimault de Freitas, Tomás A1 - Konert, Florian A1 - Nietzke, Jonathan A1 - Krzysch, Zephanja A1 - Böllinghaus, Thomas A1 - Michler, Thorsten A1 - Wackermann, Ken A1 - Oesterlin, Heiner A1 - Tlili, Mohamed A1 - Ruchti, Peter A1 - Beitelschmidt, Denise A1 - Elsen-Humberg, Stephan A1 - Koenigs, Timo A1 - Systermans, Thomas A1 - Sobol, Oded T1 - Tensile testing in high-pressure gaseous hydrogen using the hollow specimen method N2 - 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 standardized 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. The hollow specimen technique is a simple, rapid, and economical method designed to overcome the limitations of the current methods for the qualification of metallic materials under high-pressure hydrogen gas. However, this technique is not yet standardized. The TransHyDE-H2Hohlzug project is presented in this article, along with the main steps required to optimize the hollow specimen technique. This includes closing knowledge gaps related to the specimen geometry, surface quality, and gas purity in dedicated working packages, thus contributing to a comprehensive standardization of the technique for tests in high-pressure hydrogen gas. KW - High-pressure Gaseous Hydrogen KW - Hydrogen Embrittlement KW - Tensile Testing KW - Hollow Specimen Technique PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-610557 DO - https://doi.org/10.1557/s43577-024-00776-9 VL - 49 SP - 1 EP - 9 PB - Springer Nature AN - OPUS4-61055 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Konert, Florian A1 - Nietzke, Jonathan A1 - Grimault de Freitas, Tomás A1 - Rhode, Michael A1 - Sobol, Oded A1 - Böllinghaus, Thomas T1 - Investigation of resistance to gaseous hydrogen of a longitudinal weld seam in a X65 pipeline using the hollow specimen technique N2 - The constantly increasing demand for renewable energy sources leads to the necessity of transporting large amounts of hydrogen. Since pipelines enable a cost-effective way for the distribution of gaseous hydrogen, the interaction of hydrogen and the pipeline materials must be carefully investigated as hydrogen can cause a degradation of the mechanical properties under certain conditions. Especially welds, which are assumed to be more susceptible to the degradation enhanced by hydrogen, are of great interest. The aim of this study is to investigate the effect of gaseous hydrogen on the mechanical properties of an X65 pipeline, and the longitudinal submerged arc welding (SAW) welded joint. The tests are conducted using the hollow specimen technique on two types of specimens: one extracted from the base material (BM) and the other extracted as a cross-weld (CW) specimen consisting of BM and weld seam. The specimens are charged in situ under a pressure of 60 bar and tested using slow strain rate (SSR) tensile tests with a nominal strain rate of 10−5 s−1. The properties obtained of specimens tested in hydrogen atmosphere are compared to the properties of comparable specimen in inert argon atmosphere as a reference. The performed tests showed a decrease of the reduction of area (RA) from 72% in inert atmosphere to 52% in hydrogen atmosphere for the CW specimen and a decrease from 73% in inert atmosphere to 51% for the BM. Metallographic analyses showed the crack initiation between fine-grained heat-affected zone (FGHAZ) and BM for the specimens tested in hydrogen atmosphere as well as for the reference specimens. This leads to the conclusion that the location of the crack initiation does not change due to the presence of gaseous hydrogen. KW - Hydrogen KW - Hollow specimen technique KW - Pipeline KW - SSRT KW - Hydrogen embrittlement KW - Cross-weld specimen PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624658 DO - https://doi.org/10.1007/s40194-025-01953-3 SN - 0043-2288 SN - 1878-6669 VL - 69 IS - 3 SP - 861 EP - 870 PB - Springer CY - Berlin AN - OPUS4-62465 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rhode, Michael T1 - Hydrogen in Welded Microstructures of T24 Steel: Effect on Mechanical Properties and Corresponding Hydrogen Diffusion N2 - Low-alloyed CrMoV steels, such as T24, are widely used for welded components in fossil power stations due to their excellent creep-strength. Spectacular failure cases in the recent years exhibited severe cracking in T24 welds. The results showed that hydrogen-assisted cracking (HAC) occurring up to 200 degree Celsius cannot be excluded. Hence, a basic understanding is necessary on how hydrogen affects the material properties of welded microstructures. In this regard, each weld microstructure (HAZ and weld metal) has influence on the HAC susceptibility and respective hydrogen diffusion. Thus, the present contribution summarizes different results obtained from experiments with grades T24 (CrMoV alloy) and T22 (CrMo) and thermally simulated HAZ. Tensile tests were conducted with hydrogen charged specimens and compared to hydrogen-assisted stress corrosion cracking results obtained from slow strain rate tests (SSRT) up to 200 degree Celsius. Electrochemical permeation and degassing experiments were performed to identify a particular weld microstructure influence on hydrogen diffusion and trapping (especially in the HAZ). The results showed that T24 base material has improved resistance to hydrogen-assisted degradation/cracking. In contrast, the as-welded HAZ had remarkably increased susceptibility (tesnile tests at hydrogen concentration of 1 to 2 ppm). SSRT experiments confirmed this at elevated temperatures for both the T24 and the T22. Hence, the evaluation of a particular degradation of the mechanical properties should be performed independently for each weld microstructure. In addition, the HAZ showed decreased diffusion coefficients (at room temperature) of approximately one magnitude compared to the base materials. Trapped hydrogen was determined in the T24 at temperatures up to 120 degree Celsius compared to 75 degree Celsius in the T22. This has to be considered in case of changing operational temperatures, e.g. in the case of start-up and shutdown processes of boiler components. T2 - 10th Conference on Trends in Welding Research CY - Tokyo, Japan DA - 11.10.2016 KW - Degradation of Mechanical Properties KW - Hydrogen KW - Creep-resistant Steel KW - Weld Joint KW - Diffusion PY - 2016 AN - OPUS4-37827 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Grimault de Freitas, Tomás T1 - Hollow Specimen Method for Tests in High-Pressure Hydrogen Gas: The Role of Strain-Rate and Surface Quality N2 - The hollow specimen technique is a simple and economical technique that has the potential to make materials qualification with pressurised gaseous hydrogen widely accessible to academia and industry. This contribution focuses on the results obtained from assessing the influence of the specimen production and its response to hydrogen effects. Depending on the production method, different roughness and residual stresses can be expected on the inner hole surface of the specimens. This is relevant because an increase in stress concentration sites, e.g. notches, has been found to be associated with increased severity of hydrogen effects. The presence of strain-induced martensite caused by mechanical stress may also be detrimental and accelerate the embrittlement. To assess this influence, the inner hole of the hollow specimens was manufactured in two different ways: 1) only drilling; 2) EDM followed by honing. A representative steel widely used in hydrogen technologies was assessed, X5CrNi18-10 (AISI 304). Roughness measurements, and electron back-scatter diffraction (EBSD) analysis have been performed previous to mechanical testing to infer on the effect of the different production methods on the surface of the inner hole. Next, the specimens were mechanically tested via slow strain rate tensile tests in argon and in hydrogen, both at 150 bar and room temperature. Here, a strain-rate sensibility analysis was performed to investigate the influence of strain-rate on hydrogen degradation. T2 - International Conference on Hydrogen Safety 2025 CY - Seoul, South Korea DA - 22.09.2025 KW - Tensile Testing KW - Hollow Specimen Technique KW - High-Pressure Hydrogen Gas KW - Hydrogen Embrittlement KW - Surface Condition KW - Strain Rate PY - 2025 AN - OPUS4-64286 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Grimault de Freitas, Tomás T1 - Hollow Specimen Method for Tests in High-Pressure Hydrogen Gas: The TransHyDE - H2HohlZug Project N2 - As the world moves towards a decarbonised economy, the demand for sustainable and low-carbon alternatives is growing rapidly. Hydrogen has an important role to play in this transition, but in order to make the most of hydrogen as an energy carrier, a comprehensive understanding of its impact on the integrity of structural materials is necessary. Metallic materials, mainly steels, are the most commonly used structural materials in various components throughout the hydrogen supply chain. Ensuring their sustainable and safe use in hydrogen technologies is a crucial factor in the development of the hydrogen economy. This is particularly important since hydrogen can promote crack formation and ultimately lead to premature failure in these materials when combined with mechanical load. This process is commonly known as Hydrogen Embrittlement and can occur in almost all the steels used for the hydrogen technologies. Extensive materials qualification is required for the rapid implementation of hydrogen technologies, however, most accepted, and standardised test methods for determining the effect of gaseous hydrogen on metallic materials describe complex and costly procedures that are only available to a very limited extent worldwide. The hollow specimen technique is a simple and economical method that has the potential to overcome the limitations of the current methods and complement them for qualifying metallic materials under high-pressure hydrogen gas. Unlike the conventional autoclave technique, this method requires significantly lower amounts of hydrogen, resulting in fewer safety measures and no need for complex equipment or a specialised laboratory. The technique's low investment and testing costs, simple operation, and shorter testing time make it an optimal for widespread use around the world, thereby increasing the output of results. Initial studies have demonstrated the feasibility of assessing hydrogen effects in metallic materials using the hollow specimen technique. This led to the establishment of an ISO committee to standardise the method. However, there are open questions that currently prevent the technique from being standardised for hydrogen testing. These open questions relate to specimen geometry, inner hole surface and gas quality and are being addressed in the H2HohlZug project, of which the overall aim is to systematically close the gaps towards a standard. This contribution presents the structure and milestones of the project, followed by initial results. T2 - TransHyDE Vollversammlung 2025 CY - Leipzig, Germany DA - 26.11.2025 KW - Hydrogen KW - Hydrogen Embrittlement KW - Hollow Specimen Technique KW - High-Pressure Gaseous Hydrogen KW - TransHyDE KW - H2HohlZug KW - Standardisation PY - 2025 AN - OPUS4-64938 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - El Harrab, Hayat A1 - Askar, Enis A1 - Franken, T. A1 - Mauss, F. T1 - Experimental and Kinetic Study of Lubrication Oil Composition on Hydrogen Auto-Ignition N2 - Hydrogen internal combustion engines (H₂ ICEs) present a promising alternative to conventional fuels, but they face challenges such as pre-ignition, where lubricating oils play a critical role. This study investigates the auto-ignition behavior of two base oils — Group II (mineral) and Group V (Ester) — and three formulated oils (Oils A, B, and C) at 20 bar using a heated constant-volume autoclave. Oil A and Oil B share a Group II (mineral) base, with Oil A containing lower levels of calcium-based detergents and higher levels of phosphorus-based antioxidants compared to Oil B. In contrast, Oil C is formulated with a Group V (ester) base oil, incorporating magnesium-calcium detergents. The auto-ignition temperature was measured in both air and stoichiometric hydrogen-air mixtures to assess the influence of oil composition, additives, and hydrogen addition on ignition characteristics. Results show that hydrogen’s AIT at 20 bar is 460°C but drops to 270°C with the addition of 0.2 ml of base oil. Base oils exhibited similar AITs in air (260°C) and hydrogen-air mixtures (270°C), with reactivity differences linked to molecular composition — ester (Group V) displayed lower reactivity compared to mineral oil (Group II). Formulated oils demonstrated slightly higher AITs (up to 290°C), where phosphorus-based additives reduced reactivity, while lower calcium content further slowed ignition. Among the tested oils, the ester-based oil with a mixture of calcium and magnesium detergents exhibited the lowest reactivity, making it a promising candidate for hydrogen engines. Additionally, reduced oxygen availability increased AIT by 10°C and prolonged ignition delay. A chemical analysis was also performed to evaluate the ignition properties of Group II (mineral) and Group V (ester) oils under varying temperatures. These findings highlight the impact of lubricant composition on pre-ignition behavior in H₂ ICEs, offering valuable insights for optimizing lubricant formulations. T2 - 12th European Combustion Meeting CY - Edinburgh, United Kingdom DA - 07.04.2025 KW - Hydrogen KW - Pre-Ignition KW - Group V Ester Oil KW - Auto-Ignition Temperature KW - Additive Effects KW - Ignition Delay Time KW - Group II Mineral Oil KW - Lubricating Oil PY - 2025 AN - OPUS4-64761 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fedelich, Bernard T1 - Constitutive modeling and lifetime prediction for a conventionally cast Ni-base superalloy under TMF loading N2 - Under cyclic thermomechanical loading, various effects such as strain accumulation, creep damage, ageing, fatigue etc. may occur in the material of a gas turbine blade. Depending on the loading conditions, all these effects contribute to reduce the lifetime of the component. Subject of the present work is the development of a material model to describe the mechanical effects mentioned above and to subsequently predict lifetimes by using simulated stress strain data. Starting point for deformation modeling is the well known viscoplastic model after Chaboche, which provides descriptions of isotropic and kinematic hardening, as well as dynamic and static recovery. The evolution equation for kinematic hardening model has been modified following the proposal of Ohno/Wang to better predict stress controlled cyclic strain accumulation, i.e. ratchetting. A damage variable has been included to represent tertiary creep according to the concept of Kachanov. Finally, the static recovery has been modified following Kindrachuk to account for strain induced ageing. The models parameters have been calibrated using isothermal test data only. The constitutive model has been validated by comparing experimental with predicted TMF stress-strain hystereses. Lifetime prediction is done with the TMF lifetime model proposed by Riedel. The model assumes that fatigue life is controlled by the propagation of short cracks. Besides pure fatigue, it takes the local creep deformations at the crack tip into account. The model is applied to a broad variety of isothermal and non isothermal tests over temperatures up to 950°C and different loading conditions. The evaluation shows that throughout satisfying results can be achieved using a limited number of model parameters for the whole test data base. T2 - 3rd International Workshop on Thermo-mechanical fatigue CY - BAM, Berlin, Germany DA - 27.04.2016 KW - TMF KW - Nickel base superalloy KW - Fatigue life assessment KW - Constitutive law PY - 2016 AN - OPUS4-35994 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Konert, Florian T1 - Evaluation of hydrogen effect on hardened and annealed 100Cr6 steel N2 - The use of hydrogen demands high safety requirements, since hydrogen can be absorbed by metallic materials and may cause hydrogen embrittlement (HE) under certain conditions. Slow strain rate (SSR) tensile testing is a widespread method to quantify the hydrogen-induced ductility loss of alloys. Here, the hollow specimen technique was used to evaluate the effect of 150 bar hydrogen on the tensile properties of solution annealed and hardened 100Cr6 steel, which is a common material for bearing systems. This technique reduces the required amount of hydrogen and minimizes the duration and costs of the tests performed compared to in-situ tensile tests in autoclaves. T2 - EPRI Workshop on Hydrogen Embrittlement 2024 CY - Oxford, UK DA - 23.06.2024 KW - Hydrogen KW - Hydrogen Embrittlement KW - Hollow Specimen Technique KW - 100Cr6 PY - 2024 AN - OPUS4-60476 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Nietzke, Jonathan T1 - Influence of strain rate on the effect of hydrogen in pre-charged 316L stainless steel: A comparison of conventional and hollow specimen testing N2 - The growing demand for hydrogen requires an expansion of testing capabilities to assess the performance of metallic materials under hydrogen exposure. Considering only gaseous atmospheres, there is a variety of in-situ and ex-situ methods used to investigate the material behavior while or after exposed to hydrogen, respectively. Among these methods, a more conservative one is the in-situ testing at slow strain rates (SSRT) using conventional tensile specimens. While results obtained by a conservative procedure may be more applicable in many cases than those of ex-situ experiments, the tests are quite demanding, leading to limited testing capacities and high costs, especially for very slow strain rates. A possible solution that can enable in-situ testing at relatively low cost is the hollow specimen technique which gained increasing interest in the last decade. The main reasons are the minimal volume of hydrogen required and the elimination of a high-pressure hydrogen autoclave leading to significantly lower costs and enabling more laboratories worldwide to perform these tests. However, interpreting results from hollow specimens, especially when compared to conventional ones, remains a significant challenge. To address this, an experimental study was conducted using conventional and hollow specimens, both uncharged and pre-charged. Pre-charging was achieved using pure hydrogen (5.0, i.e. 99.999 %) at 100 bar and 300 °C for around 21 days. In order to obtain suitable reference specimens, other specimens were stored in argon at 100 bar and 300 °C for the same period of time. The tests were performed at various strain rates, down to 1E-6 1/s. While these ex-situ experiments are not directly comparable to in-situ tests with both types of specimens, they do provide some insights into the differences between the results of hollow and conventional specimens. Therefore, the elongation at fracture and reduction of area (RA) were compared, among other aspects. In addition, fractographical analyses were carried out using SEM images. Elongation at fracture was not significantly affected by hydrogen in conventional specimens, but it was slightly reduced in hollow specimens. RA, on the other hand, was lower for tests with hydrogen in both types of specimens across all strain rates. Moreover, the strain rate did not appear to influence hydrogen embrittlement in conventional specimens whereas in hollow specimens, tests conducted at higher strain rates (1E-4 1/s) showed a greater impact of hydrogen on elongation at fracture than those at lower strain rates (1E-6 1/s), which is contrary to the typical expectation. These findings suggest that the influence of hydrogen differs between conventional and hollow specimens, possibly due to factors such as surface roughness and differing stress states. However, further experiments are needed to fully understand these differences, including in-situ experiments to understand potential differences in hydrogen absorption between the two specimen types. T2 - EPRI Workshop on Hydrogen Embrittlement CY - Oxford, England, United Kingdom DA - 23.06.2024 KW - Stainless steel KW - Hollow specimen KW - Pre-charging KW - Hydrogen PY - 2024 AN - OPUS4-60494 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Shikomba, Nikanor A1 - Böllinghaus, Thomas A1 - Konert, Florian A1 - Sobol, Oded A1 - Blasón Gonzalez, Sergio A1 - Ohijeagbon, Idehai Olayemi A1 - Krafft, Eike A1 - Staudt, Thorsten T1 - Resistance of welded low-alloyed pressure vessel and pipeline steels in gaseous hydrogen N2 - Green hydrogen has become an essential energy carrier to achieve a climate-neutral economy. The production, storage, transport and usage of green hydrogen require safe and sustainable facilities and systems. The present contribution provides a procedure guideline to investigate the compatibility of steel welds for pressurised gaseous hydrogen applications under quasi-static mechanical loads, utilising the slow strain rate test and hollow specimen technique. Exemplarily, a weld of the low-alloyed steel P355NL1 was investigated and compared to an X65 weld. The results indicate that the base metal exhibits a higher ductility than the weld metal for both steels. Generally, hydrogen-exposed specimens exhibited a reduced strain, as compared to reference specimens. The hydrogen degradation, evaluated by the hydrogen embrittlement index, was more pronounced in the weld metal compared to the base P355NL1 material, whereas the X65 exhibited a larger hydrogen degradation of the base material than in the weld metal. Fractographic analysis of the test specimens revealed that hydrogen causes a transition from ductile to brittle features. Generally, the results of this study indicate a mild but significant degradation of the mechanical properties in terms of the ductility of the welds in the respective pressurised hydrogen atmosphere. KW - Hydrogen-assisted cracking KW - Welded joint KW - Slow strain rate test KW - Hollow Specimen KW - Structural steel PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-634138 DO - https://doi.org/10.1007/s40194-025-02074-7 SN - 0043-2288 SP - 1 EP - 15 PB - Springer CY - Berlin AN - OPUS4-63413 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Junias, Josua Kondja A1 - Holtappels, Kai A1 - Liebner, Christian A1 - Thewis, Max A1 - Askar, Enis A1 - Shaanika, Erasmus T1 - Hydrogen Mixtures Flammability Limits Prediction using Machine Learning Models N2 - Flammability characteristics of hydrogen mixtures have been extensively investigated at different initial conditions(temperature and pressure). Based on the available experimental datasets, empirical and semi-empirical models are commonly used to calculate flammability limits in dependance to initial conditions and mixture composition to reduce the experimental effort. However, unevenly distributed empirical data and the complex non-linear relationship characteristics of these data present significant challenges to empirical flammability limits prediction methods under various mixture initial conditions. Moreover, the empirical models and semi-empirical models only cover some influencing parameters, respectively. To address these issues, the present study adapts a machine learning (ML) approach for improving the hydrogen-air/oxygen-inert gas mixture flammability limits prediction at different conditions with a holistic approach. A Multi-Layer Perceptron (MLP) model was trained, validated, and tested using key input features such as flammability state, initial mixture temperature, equivalence ratio, inert gas concentration, adiabatic flame temperature, and Lewis numbers. Data augmentation techniques were conducted on experimental datasets to improve the predictive capability of the model. The models’ performance was compared with empirical flammability limit prediction methods. The goal is to deliver fast, reliable, and more accurate predictions across different scenarios with a single prediction model. Most importantly, the machine learning approach offers a cost-effective and robust alternative to existing empirical flammability limit prediction methods, thus also reducing the experimental effort for explosion limits determination. T2 - 11th International Conference on Hydrogen Safety (ICHS) 2025 CY - Seoul, South Korea DA - 22.09.2025 KW - Machine Learning KW - Flammability Limits PY - 2025 SN - 979 -12 -243 -0274 - 2 SP - 1389 EP - 1401 AN - OPUS4-64624 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Popiela, Bartosz A1 - Günzel, Stephan A1 - Mair, Georg W. T1 - Discussion of creep phenomena during initial loading of type 4 composite pressure vessels N2 - To maintain the highest safety standards for compressed gas storage in composite pressure vessels, a deeper understanding of their ageing mechanism is required. In this study, two designs of type 4 cylinders were manufactured the only difference being the internal pressure function used during the filament winding process. Hence, their residual stress state and the quality of the composite layers varied. Ten pressure vessels were initially loaded under sustained pressure and increased temperature and later subjected to slow burst tests. Comparing the results with cylinders tested in a pristine state underlines a significant improvement in the performance of initially loaded cylinders of one of the designs. This phenomenon was caused by a significant decrease of the scattering of burst pressures within a sample. At the same time, a slight decrease of the burst pressures could be observed. An explanation of this behavior could be supported by strain measurements with fiber optic sensors, which were embedded in the composite material. The strains measured during the initial loading indicate a stress redistribution, which has an impact on the strength of the pressure vessel. Moreover, an increased stiffness during the slow burst tests after initial loading was observed that indicates a better exploitation of the individual layers of the composite structure. The study supports previous observations on the increased performance after initial loading and provides new insights into the strain development in creep effects in type 4 pressure vessels. T2 - Pressure Vessels & Piping Conference PVP2025 CY - Montreal, Quebec, Canada DA - 20.07.2025 KW - Type 4 pressure vessel KW - Creep KW - Fiber optic sensors KW - Slow burst test KW - Mechanics of composites PY - 2025 SN - 978-0-7918-8907-7 VL - 2025 SP - 1 EP - 7 PB - ASME AN - OPUS4-63897 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kromm, Arne T1 - Werkstoffsichere Dickblechschweißung und KI N2 - Der Vortrag zeigt, welche Herausforderungen beim Schweißen sogenannter Dickblechverbindungen bestehen und welche Strategien zur Lösung genutzt werden können. Ansätze zur Fehlerprävention werden vorgestellt. Es wird dargestellt, wie KI-basierte Methoden die Fehlererkennung erleichtern. Letztlich werden Potentiale zur effizienten Fehlerbeseitigung aufgezeigt und der Anwendernutzen herausgestellt. T2 - Mitgliederversammlung der Forschungsvereinigung Stahlanwendung e. V. CY - Essen, Germany DA - 17.12.2025 KW - UP-Schweißen KW - Eigenspannungen KW - Künstliche Intelligenz KW - Reparatur PY - 2025 AN - OPUS4-65210 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schröpfer, Dirk T1 - Residual stress evaluation using the contour method of an additive manufactured high-strength steel solid cuboid N2 - Direct Energy Deposition with Arc (DED-Arc) enables the weight-optimized and near-net-shape manufacturing of complex structures. Lightweight construction principles allow a reduction of CO2 emissions by saving time, costs, and resources. Further optimisations can be achieved by using high-strength steel. This allows for a reduction in wall thickness and optimisation of weight. However, manufacturing intricate geometries using high-strength steels poses challenges in managing residual stresses (RS), which are essential for ensuring the structural integrity of welded components. High residual stresses can increase the risk of cold cracking, arising from the complex interactions between material properties, process conditions, and component design. Despite the availability of suitable filler metals, the lack of comprehensive knowledge and guidelines on residual stress formation limits the industrial application. Therefore, in the present study, the contour method (CM) was used to analyse the full field longitudinal residual stresses in an solid cuboid component (dimensions: 120 × 50 × 35 mm³) manufactured by DED-Arc. The CM enables the analysis of the two-dimensional map of residual stresses normal to a cutting plane using a finite element model. For this purpose, a solid cuboid component was welded fully automatically with a high-strength solid wire specially adapted for DED-Arc (yield strength > 790 MPa) onto conventionally manufactured substrates made of S690QL. The residual stresses from CM in the volume are compared with residual stress analyses using X-Ray diffraction on the surface. Additionally, comparative data from previous studies on hollow cuboid structures was included in order to identify similarities and differences in the resulting stress state, and to complement and validate the CM results. These results demonstrate the significant influence of the geometry on the residual stress profiles within the solid cuboid in relation to the open hollow. T2 - 4th International Conference on Advanced Joining Processes 2026 CY - Coimbra, Portugal DA - 16.10.2025 KW - Residual stress KW - Contour method KW - DED-Arc/M KW - High-strength steel KW - Filler metals KW - Neutron diffraction PY - 2025 AN - OPUS4-65209 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pittner, Andreas A1 - Fabry, Cagtay A1 - Thiele, Marc A1 - Artinov, Antoni A1 - Rethmeier, Michael T1 - Automated Arc Welding and Sensor Based Quality Assessment for Enhancing Fatigue Strength and Structural Reliability of Offshore Wind Turbine Supports N2 - Offshore wind energy plays a crucial role in achieving a carbon dioxide free industrial sector in the coming decades. However, foundation systems for offshore wind turbines significantly impact the overall installation process, posing technical and regulatory challenges. Adopting lightweight design principles in steel construction such as dissolved load bearing structures in jacket foundations offers substantial potential for reducing resource consumption, particularly steel usage. This presentation explores the complete digitalization of welding manufacturing and testing processes, enabling fully automated production and data driven quality assessment of tubular nodes, which are vital components of jacket foundations. The study also investigates the relationship between seam geometry and fatigue strength inspired by bionic design principles. The results demonstrate that tubular nodes can be welded entirely automatically, accommodating geometric tolerances, and that seam geometries ca n be precisely manufactured according to suggestions from e.g. numerical models or other sources . These advancements significantly enhance the fatigue strength and service life of offshore wind turbine support structures. T2 - IIW Annual Assembly 2025 CY - Genova, Italy DA - 23.06.2025 KW - Automated gas metal arc welding KW - Quality assessment and control KW - Support structures KW - Fatigue PY - 2025 AN - OPUS4-65232 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Graebner, Maraike A1 - Giese, Marcel A1 - Lorenz, Svenja A1 - Treutler, Kai A1 - Schröpfer, Dirk A1 - Wesling, Volker A1 - Kannengießer, Thomas T1 - Wear resistance of modified NiMoCrSi claddings in relation to the resulting surface machinability via ultrasonic-assisted milling N2 - In the field of plastics processing, extruder screws are subjected to significant wear stresses. The extruder screw is the main wear component in those production machines and is usually coated with intermetallic wear protection alloys composed of Ni-based alloys, specifically Colmonoy C56 PTA (NiMoCrSi). There is a growing demand for providing an economic machinability of these alloys to achieve defined contours with a sufficient surface integrity. Recent investigations exhibit promising results applying ultrasonic milling for such hard-to-cut materials. The Colmonoy C56 is modified by various alloying additions Ti, Nb, Mo, Hf, and Al, and then cladded on a steel S355 via Plasma Transferred Arc process. The effect of alloying additions on the microstructure is analyzed regarding their resistance to abrasive and adhesive wear. With Miller test ASTM G75 the influence of alloying elements on resistance to abrasive wear for two abrasive materials is investigated (high-grade corundum F220 and quartz powder). The wear loss is not increased for additions of Nb and Ti compared to the base material C56. Modifications with Hf or Al reduces the resistance to abrasive wear and significantly increases material loss. The extruder screw is also subject to adhesive wear, which can be quantified by means of the pin-roll test. It is demonstrated that the addition of Hf, for example, contributes to a reduction in wear loss. Aim of the investigations is to find suitable modifications for the wear claddings of C56 for a sufficient machineability, without compemising the wear resistant. The machinability is considerably affected by the alloy additions, and is determined using ultrasonic-assisted milling. The addition of hafnium reduces machinability, i.e. significantly increases cutting forces. The incorporation of Nb exhibits a significant reduction of cutting forces, and results in reduced tool wear and an enhanced of surface integrity (roughness, density of defects, residual stresses). KW - Colmonoy C56 KW - PTA welding KW - Adhesive wear KW - Abrasive wear KW - Ultrasonic-assisted milling process KW - Surface integrity KW - Service life and efficiency KW - Substitution of critical raw materials PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-651530 DO - https://doi.org/10.1016/j.wear.2025.205830 SN - 0043-1648 VL - 571 SP - 1 EP - 10 PB - Elsevier B.V. AN - OPUS4-65153 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gluth, Gregor T1 - Inhalt der Verordnungen für Heizungsanlagen - Überblick N2 - Seit dem 26.09.2015 gelten in Deutschland Anforderungen an die umweltgerechte Gestaltung und die Energiekennzeichnung von Heizgeräten und Verbundanlagen mit Heizgeräten. Der Vortrag stellt die zugrundeliegenden EU-Verordnungen und die sich ergebenden Konsequenzen überblicksmäßig vor. T2 - Kolloquium Marktüberwachung im Bereich Heizungsanlagen CY - Berlin, Germany DA - 06.04.2016 KW - Heizgeräte KW - Verbundanlagen KW - Umweltgerechte Gestaltung KW - Ökodesign KW - Energieverbrauchskennzeichnung PY - 2016 AN - OPUS4-36924 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Askar, Enis T1 - Hydrogen Safety - Explosion Protection for Hydrogen Applications N2 - In this lecture the safety related properties og hydrogen compared to other fuel gases and the explosion protection measures of avoiding flammable mixtures, avoiding ignition sources and mitigating the consequences of explosions when handling hydrogen and hydrogen mixtures are presented. The Joint European Summer School JESS 2021 addresses these issues by offering high quality graduate level courses on selected topics of vehicle technology, innovation & business development, safe handling of hydrogen, and modelling. The course content is tailored to the needs of a diverse audience: newcomers to the field, experienced students, and young professionals working at the forefront of fuel cell and hydrogen applications. T2 - Joint European Summer School (JESS) CY - Online meeting DA - 06.09.2021 KW - Explosionsschutz KW - Explosionsgrenzen KW - Zündenergie KW - Zündquellen KW - Auswirkung von Explosionen PY - 2021 AN - OPUS4-53808 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Askar, Enis A1 - Schröder, Volkmar A1 - Seemann, A. A1 - Schuetz, S. T1 - Power-to-Gas: Safety Characteristics of Hydrogen/NaturalGas-Mixtures N2 - Safety characteristics for explosion protection of natural gas/hydrogen mixtures relevant in connection with the Power2Gas technology were studied in this work. Lower explosion limits (LEL) and upper explosion limits (UEL), limiting oxygen concentrations (LOC), maximum experimental safety gaps (MESG), maximum explosion pressures (pmax) and maximum rates of pressure rise (dp/dt)max were determined experimentally in dependence of the hydrogen fraction. Adding hydrogen did mainly effect the UEL, LOC, MESG and (dp/dt)max. The mixtures become more "critical" concerning the explosion hazards with increasing hydrogen fraction. However, the dependency of the safety characteristics from the hydrogen fraction is mainly not linear. Adding up to 10% hydrogen to natural gas had nearly no effect on the safety characteristics. More significant effects on the safety characteristics were observed at hydrogen fractions of more than 25%. For example the explosion group changes from IIA to IIB. Considering the huge explosion region and very high (dp/dt)max of hydrogen compared to natural gas, even adding 50% hydrogen to natural gas has a rather small effect on these characteristics. Furthermore pmax of hydrogen/natural-gas mixtures can be calculated with good accuracy assuming ideal adiabatic conditions. EL and LOC of natural gas/hydrogen mixtures in ternary systems with inert gas and air were calculated in dependence of the type of inert gas with the so called “model of constant adiabatic flame temperature profiles”. KW - Explosion protection KW - Hydrogen safety KW - Hydrogen enriched natural gas KW - Energy storage PY - 2016 SN - 78-88-95608-39-6 DO - https://doi.org/10.3303/CET1648067 SN - 2283-9216 VL - 2016/48 SP - 397 EP - 402 PB - AIDIC AN - OPUS4-36788 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sobol, Oded T1 - BAM’s role in materials science and hydrogen in metals: TOF-SIMS imaging N2 - Due to its low mass and high diffusivity in presence of compositional, thermal and mechanical gradients, hydrogen within a metallic microstructure can result in severe loss in ductility even at low concentrations and might lead eventually to a catastrophic and unpredictable failure of structural components during service. In this context, hydrogen mapping at the microscale is still considered among the most important challenges on the pathway towards a better understanding of the hydrogen transport and assisted cracking phenomena in metals, specifically in structural components, e.g. steels. Among the very few available techniques to localize hydrogen at the microscale, Time-of-flight secondary ion mass spectrometry (ToF-SIMS) was proven to be a reliable tool. Based on the assumption that deuterium influence the microstructure similarly to hydrogen, in the following contribution ToF-SIMS was applied as the main technique to detect and locally map the deuterium distribution in several alloys: lean 2101 and standard 2205 duplex stainless steel (DSS), AISI 304L austenitic stainless steel and titanium 6Al-4V alloy. These alloys were selected as case studies in this work due to the wide use of them in many applications and environments which frequently provide critical conditions for hydrogen absorption and assisted degradation. The innovative design of in-situ and ex-situ experiments enabled us to elucidate the permeation, transport and trapping of deuterium in the microstructure in sub-micron resolution for the first time. In addition to the novel experimental setups, further progress was gained by applying computational multivariate data analysis (MVA) on the raw data and data fusion with high resolution structural characterization methods (scanning electron microscopy and electron back-scattered diffraction – SEM/EBSD). This combination allowed us to correlate the deuterium distribution and the influence on the microstructure. T2 - 4th Symposium on Innovative Measurement and Analysis for Structural Materials CY - Tokyo, Japan DA - 13.11.2018 KW - ToF-SIMS KW - Duplex stainless steel KW - Austenitic stainless steel KW - Principal Component Analysis KW - Data-fusion PY - 2018 UR - https://unit.aist.go.jp/tia-co/project/SIP-IMASM/sympo/2018/index.html AN - OPUS4-46867 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Epishin, A. I. A1 - Link, T. A1 - Nolze, Gert A1 - Svetlov, I. L. A1 - Bokshtein, B. S. A1 - Rodin, A. O. A1 - Saliwan Neumann, Romeo A1 - Oder, Gabriele T1 - Diffusion processes in multicomponent nickel-base superalloy-nickel system N2 - Optical and scanning electron microscopy, as well as electron microprobe analysis and electron backscatter diffraction, have been used to study diffusion processes that occur in a diffusion pair that consistsof a single-crystal CMSX-10 nickel-base superalloy and polycrystalline nickel, at temperatures of 1050–1250°C. It has been found that, in this system, the distributions of γ-stabilizing elements (Cr, Co, W, and Re) are described by the Boltzmann solution for diffusion between two semiinfinite plates of a binary alloy. The processing of these distributions has shown that the diffusion coefficients of Cr, Co, W, and Re in the multicomponent system are close to those in binary alloys of these elements with Ni. The diffusion redistribution of the elements leads to the dissolution of the γ′ phase in the nickel-base superalloy, growth of nickel grains toward the superalloy constituent of the diffusion pair, and the formation of porosity on both sides of the migrating interface, which is determined from a crystal misorientation of the alloy single crystal and nickel grains. KW - Ni-base superalloy KW - Interface KW - Diffusion KW - Phase transformation KW - Porosity PY - 2014 SN - 0031-918X VL - 115 IS - 1 SP - 21 EP - 29 AN - OPUS4-37980 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Askar, Enis T1 - Ignition Behaviour and Challenges for Hydrogen Safety N2 - The presentation is divided in two parts. In the first part the significance of mechanical impacts as ignition source for hydrogen containing atmospheres is shown and recent results of a research project evaluating ignition probabilities under different conditions is presented. In the second part future challenges in the field of hydrogen safety are discussed. Finally, the German National Hydrogen Safety Alliance is introduced. T2 - Hydrogen Online Workshop 2024 CY - Online meeting DA - 05.06.2024 KW - Explosion protection KW - Mechanical impacts KW - Ignition source KW - German National Alliance for Hydrogen Safety PY - 2024 AN - OPUS4-60288 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Schröder, Volkmar A1 - Askar, Enis A1 - Habib, Abdel Karim A1 - Tashqin, T. T1 - Sicherheitstechnische Eigenschaften von Erdgas-Wasserstoff-Gemischen N2 - Bei der Power-to-Gas-Technologie wird überschüssiger Strom aus erneuerbaren Energien durch Elektroly-se von Wasser in Wasserstoff umgewandelt. Dieser Wasserstoff kann als „chemischer Energiespeicher“ dienen und rückverstromt werden oder aber in das Erdgasnetz eingespeist werden. Die BAM hat die Aus-wirkungen von Wasserstoffzusätzen zum Erdgas im Hinblick auf den Explosionsschutz untersucht und sicherheitstechnische Kenngrößen für Erdgas-Wasserstoff-Gemische bestimmt. Untersucht wurden die Explosionsgrenzen, die Sauerstoffgrenzkonzentrationen, die maximalen Explosi-onsdrücke, die KG-Werte und die Normspaltweiten. Für die Messungen sind zwei Modellgase eingesetzt worden, reines Methan und ein Modell-Erdgas mit Anteilen höherer Kohlenwasserstoffe. Sie repräsentie-ren die Bandbreite der in Deutschland eingesetzten Erdgase. Die Untersuchungen ergaben, dass bei einem Zusatz von bis zu 10 Mol-% Wasserstoff keine der untersuchten Kenngrößen relevant beeinflusst wird. Die Gemische haben nur geringfügig erweiterte Explosionsbereiche und bleiben, wie die reinen Erdgase, in der Explosionsgruppe IIA. Auch die maximalen Explosionsdrücke und die zeitlichen Druckanstiege bei den Gasexplosionen werden nur wenig beeinflusst. Vergleichende Berechnungen zur Festlegung von explosionsgefährdeten Bereichen (Ex-Zonen) auf Basis von Gasausbreitungsberechnungen ergaben ebenfalls nur geringfüge Unterschiede im Rahmen der Fehler-toleranz für Erdgas und Erdgas-Wasserstoff-Gemische mit bis zu 10 Mol-% Wasserstoff. Die Berechnun-gen sind in der BAM nach einem Freistrahlmodell von Schatzmann und mit dem häufig bei Gasnetzbetrei-bern eingesetzten e.BEx-Tool® durchgeführt worden. Der Einsatz von Gaswarngeräten, die für reines Erdgas geeignet sind, ist für Erdgas-Wasserstoff-Gemische mit bis zu 10 Mol-% Wasserstoff grundsätzlich möglich, erfordert aber eine gesonderte Sicher-heitsbewertung und ggf. eine Nachkalibrierung. N2 - Power-to-Gas technology is used to convert excess power from renewable energies to hydrogen by means of water electrolysis. This hydrogen can serve as "chemical energy storage" and be converted back to elec-tricity or be fed into the natural gas grid. BAM has studied the addition of hydrogen to natural gas in view of explosion protection and has determined safety characteristics for natural gas-hydrogen mixtures. BAM investigated the explosion limits, the limiting oxygen concentrations, the maximum explosion pres-sures, KG values and the MESG. Two model gases have been investigated, pure methane and a model gas with portions of higher hydrocarbons. They represent the range of natural gases which are used in Germa-ny. The investigations have shown that none of the examined characteristics is affected significantly by the addition of up to 10 mol% hydrogen. The explosion ranges are increased only slightly and the mixtures remain in explosion group IIA; as is pure natural gas. Also the maximum explosion pressure and the rates of pressure rise of gas explosions are almost unaffected. Comparative calculations – on the basis of gas dispersion calculations – to determine hazardous areas (explosion zones) for pure natural gas and natural gas-hydrogen mixtures with up to 10 mol% hydrogen, also revealed only minor differences within the margin of error of the calculation methods. The calcula-tions were executed at BAM according to the free jet model from Schatzmann and with the e.BEx-Tool®, often applied by gas grid operators. In principle, gas detectors that are suitable for natural gas can be used for natural gas-hydrogen mixtures with a maximum of 10 mol% hydrogen. However, this requires a separate safety assessment and, if nec-essary, a recalibration. KW - Power-to-Gas KW - Erneuerbare Energien KW - Energiespeicherung KW - Wasserstofftechnologie KW - Explosionsschutz KW - Erdgas-Wasserstoff-Gemische PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-372977 SP - 1 EP - 36 PB - Bundesanstalt für Materialforschung und -prüfung (BAM) CY - Berlin AN - OPUS4-37297 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schröder, Volkmar A1 - Askar, Enis A1 - Tashqin, T. T1 - Sicherheitstechnische Eigenschaften von Gemischen aus Wasserstoff und Erdgas N2 - Bei der Power-to-Gas-Technologie wird überschüssiger Strom aus erneuerbaren Ener-gien durch Elektrolyse von Wasser in Wasserstoff umgewandelt. Dieser Wasserstoff kann als „chemischer Energiespeicher“ dienen und rückverstromt werden oder aber in das Erdgasnetz eingespeist werden. Die BAM hat die Auswirkungen von Wasserstoffzu-sätzen zum Erdgas im Hinblick auf den Explosionsschutz untersucht und sicherheitstechnische Kenngrößen für Erdgas-Wasserstoff-Gemische bestimmt. Von besonderem Interesse waren dabei die Explosionsgrenzen, die Sauerstoffgrenzkonzentration, die maximalen Explosionsdrücke, die KG-Werte und die Normspaltweiten. Für die Messungen sind zwei Modellgase eingesetzt worden, reines Methan und ein Modell-Erdgas mit Anteilen höherer Kohlenwasserstoffe. Sie repräsentieren die Bandbreite der in Deutschland eingesetzten Erdgase. Die Untersuchungen ergaben, dass bei einem Zusatz von bis zu 10 Mol-% Wasserstoff keine der untersuchten Kenngrößen signifikant beeinflusst wird. Die Gemische haben nur geringfügig erweiterte Explosionsbereiche und bleiben, wie die reinen Erdgase, in der Explosionsgruppe IIA. Auch die maximalen Explosionsdrücke und die zeitlichen Druckanstiege bei den Gasexplosionen werden nur wenig beeinflusst. T2 - Kolloquium zur chemischen und physikalischen Sicherheitstechnik CY - Berlin, Germany DA - 14.06.2016 KW - Wasserstoff KW - Erdgasnetz KW - Energiespeicherung KW - Explosionsschutz KW - Sicherheitstechnische Kenngrößen PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-373099 SN - 978-3-9817853-5-7 SN - 0938-5533 VL - 2016 SP - 60 EP - 67 PB - Bundesanstalt für Materialforschung und -prüfung (BAM) CY - Berlin, Germany AN - OPUS4-37309 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Askar, Enis T1 - Sicherheitstechnische Eigenschaften von Erdgas/Wasserstoff-Gemischen - Auswirkungen auf den Explosionsschutz N2 - Hinsichtlich ihrer sicherheitstechnischen Kenngrößen (STK) unterscheiden sich Wasserstoff und Erdgas zum Teil stark. Im Vortrag werden verschiedene STK von Erdgas/Wasserstoff-Gemischen im Abhängigkeit des Wasserstoffanteils vorgestellt und die Auswirkung der Beimischung von Wasserstoff zum Erdgas auf die Wirksamkeit von Explosionsschutzmaßnahmen erläutert. T2 - DVGW-Kongress 2021 "Gasinfrastruktur für Erdgas-H2-Gemische" CY - Online meeting DA - 07.10.2021 KW - Explosionsschutz KW - Explosionsgrenzen KW - Zündenergie KW - Power to Gas KW - Erdgasnetz KW - Zündquellen PY - 2021 AN - OPUS4-53725 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mosquera Feijoo, Maria T1 - Thermal-mechanical fatigue of oxide scales in cyclic water vapor oxidation of 9-12 % Cr steels N2 - Ferritic-martensitic steels with 9-12 % Cr-content are widely used as high temperature construction materials in power plant due to their high temperature properties such as creep resistance, strength, and favorable oxidation resistances. However, typical operating conditions include cyclic thermal/mechanical loading, and as a result the oxide scale might fail; cracks are formed and the oxide scale is spalled off. The oxide spalls can cause steam tube blocking and local thermal stresses, which might provoke shorter component service life. This work investigates the scale spallation behavior of ferritic-martensitic steels under cyclic load condition between 320°C and 620°C for up to 210 cycles in pure steam. All samples were isothermally pre-oxidized at 620°C for 500 h in water steam with 30 bar pressure to create an initial magnetite layer with low porosity. Different sample shapes, rectangular coupons, full rings and U-shape segments, are investigated to evaluate the impact of the geometry on these conditions. After oxidation experiments the oxidation kinetics in terms of mass change, metal loss and thickness scale is determined. In addition, the integrity of the oxide layer as well as its adherence to the matrix are characterized by modified hardness tests and scratch tests. Breakage of the layers at lower applied forces indicates a substantial loss of adhesion strength at intermediate cycle numbers. T2 - EUROCORR 2017 CY - Prague, Czech-Republic DA - 03.09.2017 KW - Geometry influence KW - Therma-mechanical fatigue KW - Oxide layer KW - Cyclic test KW - Scale adherence PY - 2017 AN - OPUS4-42635 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Röhsler, Andreas A1 - Sobol, Oded A1 - Hänninen, H. A1 - Böllinghaus, Thomas T1 - In-situ ToF-SIMS analyses of deuterium re-distribution in austenitic steel AISI 304L under mechanical load N2 - Hydrocarbons fuel our economy. Furthermore, intermediate goods and consumer products are often hydrocarbon-based. Beside all the progress they made possible, hydrogen-containing substances can have severe detrimental effects on materials exposed to them. Hydrogen-assisted failure of iron alloys has been recognised more than a century ago. The present study aims to providing further insight into the degradation of the austenitic stainless steel AISI 304L (EN 1.4307) exposed to hydrogen. To this end, samples were electrochemically charged with the hydrogen isotope deuterium (2H, D) and analysed by scanning electron microscopy (SEM), electron back-scatter diffraction (EBSD) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). It was found that deuterium caused a phase transformation from the original γ austenite into ε- and α’-martensite. Despite their low solubility for hydrogen, viz. deuterium, the newly formed phases showed high deuterium concentration which was attributed to the increased density of traps. Information about the behaviour of deuterium in the material subjected to external mechanical load was gathered. A four-point-bending device was developed for this purpose. This allowed to analyse in-situ pre-charged samples in the ToF-SIMS during the application of external mechanical load. The results indicate a movement of deuterium towards the regions of highest stress. KW - ToF-SIMS KW - Hydrogen KW - Deuterium KW - AISI 304L KW - EBSD PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-505142 DO - https://doi.org/10.1038/s41598-020-60370-2 VL - 10 IS - 1 SP - 3611 PB - Nature AN - OPUS4-50514 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Konert, Florian A1 - Campari, Alessandro A1 - Nietzke, Jonathan A1 - Sobol, Oded A1 - Paltrinieri, Nicola A1 - Alvaro, Antonio T1 - Evaluation of the tensile properties of X65 pipeline steel in compressed gaseous hydrogen using hollow specimens N2 - Hydrogen has great potential on the path towards decarbonization of the energy and transport sectors and can mitigate the urgent issue of global warming. It can be sustainably produced through water electrolysis with potentially zero emissions, and efficiently used (e.g., in fuel cell systems). Despite its environmental advantages, hydrogen-metal interactions could result in the degradation of the mechanical properties of several structural materials. In order to determine the magnitude of the material degradation in relation to hydrogen exposure, extensive material testing is required. The standardized procedure for in-situ testing for the quantification of the impact of compressed gaseous hydrogen (CGH2) relies on the utilization of an autoclave around the tested specimen. Such test set-up is complex, expensive, time-consuming and requires special equipment, trained personnel, and strict safety procedures. A relatively recent method to circumvent these issues and provide affordable results consists of using hollow specimens, thus applying the hydrogen pressure inside rather than outside the specimen. It allows to reduce the volume of hydrogen by several orders of magnitude and to perform the tests more efficiently and in a safer manner. This study focuses on evaluating the tensile properties of X65 vintage pipeline steel tested in a high-pressure hydrogen environment using hollow specimens. Tests are performed in 6 MPa H2 and Ar at the nominal strain rate of 10−6 s−1 to evaluate the reduced area at fracture and the elongation loss. The effect of surface finishing on crack initiation and propagation is investigated by comparing two different manufacturing techniques. In this way, this study provides insights into the applicability of a novel, reliable, and safe testing method which can be used to assess the hydrogen-assisted ductility loss in metallic materials. KW - Mechanical Engineering KW - Hydrogen Embrittlement KW - SSRT KW - Hollow specimen KW - Pipeline steel KW - In-situ tensile test PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595887 DO - https://doi.org/10.1016/j.prostr.2024.01.074 SN - 2452-3216 VL - 54 SP - 1 EP - 8 PB - Elsevier B.V. AN - OPUS4-59588 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Konert, Florian A1 - Wieder, Frank A1 - Nietzke, Jonathan A1 - Meinel, Dietmar A1 - Böllinghaus, Thomas A1 - Sobol, Oded T1 - Evaluation of the impact of gaseous hydrogen on pipeline steels utilizing hollow specimen technique and μCT N2 - The high potential of hydrogen as a key factor on the pathway towards a climate neutral economy, leads to rising demand in technical applications, where gaseous hydrogen is used. For several metals, hydrogen-metal interactions could cause a degradation of the material properties. This is especially valid for low carbon and highstrength structural steels, as they are commonly used in natural gas pipelines and analyzed in this work. This work provides an insight to the impact of hydrogen on the mechanical properties of an API 5L X65 pipeline steel tested in 60 bar gaseous hydrogen atmosphere. The analyses were performed using the hollow specimen technique with slow strain rate testing (SSRT). The nature of the crack was visualized thereafter utilizing μCT imaging of the sample pressurized with gaseous hydrogen in comparison to one tested in an inert atmosphere. The combination of the results from non-conventional mechanical testing procedures and nondestructive imaging techniques has shown unambiguously how the exposure to hydrogen under realistic service pressure influences the mechanical properties of the material and the appearance of failure. KW - Energy Engineering and Power Technology KW - Condensed Matter Physics KW - Fuel Technology KW - Renewable Energy, Sustainability and the Environment KW - µCT KW - Hollow Specimen Technique KW - Hydrogen Embrittlement PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595077 DO - https://doi.org/10.1016/j.ijhydene.2024.02.005 SN - 0360-3199 VL - 59 SP - 874 EP - 879 PB - Elsevier B.V. AN - OPUS4-59507 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Epishin, A. A1 - Link, T. A1 - Svetlov, I. L. A1 - Nolze, Gert A1 - Saliwan Neumann, Romeo A1 - Lucas, H. T1 - Mechanism of porosity growth during homogenisation in single crystal nickel-based superalloys N2 - Several mechanisms for porosity growth in single crystal nickel-based superalloys during homogenisation heat treatment have been proposed in the literature. They were carefully checked using different experimental methods, namely quantitative light microscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffraction and density measurements. It is shown that the main mechanism is the Kirkendall–Frenkel effect, i.e. generation of voids due to uncompensated efflux of Al atoms from dissolving γ/γ′-eutectic areas. The Al diffusion is supported by the afflux of vacancies from surrounding γ-matrix which results in porosity growth. This conclusion is confirmed by the estimation of the vacancy afflux towards the dissolving eutectic. KW - Ni-base superalloy KW - Eutectic KW - Vacancies KW - Porosity PY - 2013 VL - 104 IS - 8 SP - 776 EP - 782 PB - Carl Hanser Verlag AN - OPUS4-37983 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Leo, Reinhold T1 - Duplex stainless steels - Compatibility for high-pressure hydrogen applications N2 - Duplex Stainless Steels (DSS) are an essential component used in the construction of transportation pipelines because of their many distinctive qualities. The choice of DSS for a particular hydrogen application mainly depends on its susceptibility level to Hydrogen Assisted Cracking (HAC). Several mechanisms have been proposed to describe the occurring microscale processes behind HAC, and these include metastable phase transformation, Hydrogen Enhanced Localized Plasticity (HELP), and Hydrogen Enhanced Decohesion (HEDE). This contribution describes the path to ascertain if DSS is suitable for high-pressure gaseous hydrogen applications. The interplay between several critical factors that result in HAC was examined using high-pressure gaseous hydrogen charging, Electron Backscatter Diffraction (EBSD), tensile testing and hydrogen concentration measurements using Carrier Gas Hot Extraction (CGHE). T2 - Third German-African Green Hydrogen Forum 2025 CY - Bernburg (Saale), Germany DA - 23.09.2025 KW - Hydrogen Assisted Cracking KW - High Pressure Hydrogen KW - Duplex Stainless Steels KW - Hollow Specimen Technique PY - 2025 AN - OPUS4-64302 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Askar, Enis A1 - Grunewald, Thomas T1 - Entzündung von wasserstoffhaltigen Atmosphären durch mechanisch erzeugte Funken („HySpark“) N2 - Im Zuge der Energiewende finden Wasserstofftechnologien in der industriellen Praxis und im öffentlichen Raum immer mehr Anwendung. Beim Einsatz von Wasserstoff als Ersatz für andere fossile Energieträger wie Erdgas müssen u.a. Explosionsschutzmaßnahmen überprüft und angepasst werden. Eine Art von Explosionsschutzmaßnahmen ist die Vermeidung von Zündquellen. Gemäß den einschlägigen Regelwerken ist die Bildung von Funken oder heißen Aufschlagstellen beim mechanischen Schlag eine mögliche Zündquelle, die vor allem beim Wasserstoff berücksichtigt werden muss. Die Zündwirksamkeit ist dabei u.a. stark von der Werkstoffpaarung und der kinetischen Schlagenergie abhängig. Der Einsatz von funkenarmen Werkzeugen aus schwer oxidierbaren Nicht-Eisen-Metallen in explosionsgefährdeten Bereichen kann z.B. eine Maßnahme sein, um diese Zündquelle zu vermeiden und wird als solche in den Regelwerken benannt. Es gibt aber kaum Quellen, die dabei helfen die Zündwirksamkeit bei Schlägen mit heterogenen Materialpaarungen einzuschätzen. In dieser Arbeit wurde zu diesem Zweck die Zündwirksamkeit von mechanischen Schlägen mit unterschiedlichen, auch nicht-metallischen Schlagpartnern in wasserstoffhaltigen Atmosphären systematisch untersucht. KW - Explosionsschutz KW - Zündquelle KW - ATEX KW - Erdgas KW - Mechanischer Schlag PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-579869 DO - https://doi.org/10.26272/opus4-57986 SP - 1 EP - 28 AN - OPUS4-57986 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Baer, Wolfram A1 - Wossidlo, Peter T1 - Experimental determination and analysis of dynamic fracture toughness data of ductile cast iron N2 - Ductile Cast Iron materials (DCI) have become important structural materials. Neverthe-less, to draw maximum benefit from DCIs property potential, tailored testing methods must be provided. The established dynamic Jd-R and CTOD 5d-R curve procedures are based on material specifically developed, independent experimental techniques but pro-vide almost matching results. This can be seen as additional validation of the Jd procedure which was mandatory. T2 - 14th International Conference on Fracture (ICF 14) CY - Rhodes, Greece DA - 18.07.2017 KW - Ductile cast iron KW - Fracture mechanics KW - Dynamic loading KW - Crack resistance curve KW - CTOD KW - J-integral PY - 2017 SP - Track 3, 1 EP - 2 AN - OPUS4-42721 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Baer, Wolfram A1 - Holzwarth, Marcel A1 - Mayer, Uwe ED - Vormwald, Michael T1 - Untersuchung des Master Curve-Konzepts für ferritisches Gusseisen mit Kugelgraphit: Versuchswerkstoff und erste Ergebnisse an SE(B)140-Großproben N2 - In einem laufenden Kooperationsprojekt zwischen der BAM Berlin und der MPA Stuttgart wird das probabilistische Master Curve (MC) Konzept nach ASTM E1921 hinsichtlich seiner Übertragbarkeit auf ferritisches Gusseisen mit Kugelgraphit (DCI) untersucht. Zielsetzung ist die Bereitstellung einer Vorgehensweise zur Bestimmung und Bewertung der dynamischen Bruchzähigkeit von DCI im Übergangsbereich. In diesem Beitrag wird der Versuchswerkstoff der Festigkeitsklasse GJS-400 näher vorgestellt. Ferner werden erste Ergebnisse von zwei bruchmechanischen Versuchsserien an SE(B)140-Großproben bei Belastungsraten von ca. 6∙104 MPa√ms-1 bei -40 °C und -60 °C präsentiert. T2 - 56. Tagung des DVM-Arbeitskreises Bruchmechanik und Bauteilsicherheit CY - Kassel, Germany DA - 20.02.2024 KW - Dynamische Beanspruchung KW - Bruchmechanik KW - Master Curve-Konzept KW - Gusseisen mit Kugelgraphit PY - 2024 DO - https://doi.org/10.48447/BR-2024-BB SP - 49 EP - 58 PB - DVM-Verlag CY - Berlin AN - OPUS4-59518 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Holzwarth, Marcel A1 - Baer, Wolfram A1 - Mayer, Uwe A1 - Weihe, Stefan ED - Vormwald, Michael T1 - Untersuchung des Master Curve-Konzepts für ferritisches Gusseisen mit Kugelgraphit: Kritische Belastungsrate und erste Ergebnisse an C(T)-Proben N2 - Im laufenden Verbundprojekt MCGUSS untersuchen dieProjektpartner MPA Stuttgart und BAM Berlin das probabilistische Master Curve (MC) Konzept nach ASTM E1921 hinsichtlich seiner Übertragbarkeit auf ferritisches Gusseisen mit Kugelgraphit (DCI). Ziel des Projektes ist die Entwicklung einer Methode zur Bestimmung und Bewertung der dynamischen Bruchzähigkeit von DCI im Übergangsbereich. In diesem Beitrag werden die Eigenschaften des verwendeten Werkstoffs der Festigkeitsklasse GJS-400 vorgestellt und die sich daraus ergebenden Probenentnahmestellen näher erläutert. Weiterhin werden erste Ergebnisse der C(T)25-Versuchsserien vorgestellt, die bei Belastungsraten von ca. 5∙103 MPa√ms-1, 5∙104 MPa√ms-1 und 5∙105 MPa√ms-1 und einer Temperatur von -40 °C durchgeführt wurden. T2 - 56. Tagung des DVM-Arbeitskreises Bruchmechanik und Bauteilsicherheit CY - Kassel, Germany DA - 20.02.2024 KW - Dynamische Belastung KW - Master Curve KW - Gusseisen KW - C(T)-Proben PY - 2024 SP - 37 EP - 47 PB - DVM Verlag CY - Berlin AN - OPUS4-59519 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Baer, Wolfram T1 - Untersuchung des Master Curve-Konzepts für Ferritisches Gusseisen mit Kugelgraphit: Versuchswerkstoff und erste Ergebnisse von SE(B)140-Grossproben N2 - In einem laufenden Kooperationsprojekt zwischen der BAM Berlin und der MPA Stuttgart wird das probabilistische Master Curve (MC) Konzept nach ASTM E1921 hinsichtlich seiner Übertragbarkeit auf ferritisches Gusseisen mit Kugelgraphit (DCI) untersucht. Zielsetzung ist die Bereitstellung einer Vorgehensweise zur Bestim-mung und Bewertung der dynamischen Bruchzähigkeit von DCI im Übergangsbe-reich. In diesem Beitrag wird der Versuchswerkstoff der Festigkeitsklasse GJS-400 näher vorgestellt. Ferner werden erste Ergebnisse von zwei bruchmechanischen Versuchsserien an SE(B)140-Großproben bei Belastungsraten von ca. 6∙104 MPa√ms-1 bei -40 °C und 60 °C präsentiert. T2 - Jahrestagung des DVM-Arbeitskreises Bruchmechanik und Bauteilsicherheit CY - Kassel, Germany DA - 20.02.2024 KW - Bruchzähigkeit KW - Sprödbruch KW - Master Curve KW - Gusseisen mit Kugelgraphit KW - ASTM E1921 PY - 2024 AN - OPUS4-59860 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mayer, Uwe T1 - Untersuchung des Master Curve-Konzeptes für ferritisches Gusseisen mit Kugelgraphit N2 - In dem Poster werden der Forschungsansatz, die Ziele, das Untersuchungsprogramm und die erwarteten Ergebnisse des BMUV-Forschungsvorhabens MCGUSS "Untersuchung des Master Curve-Konzeptes für ferritisches Gusseisen mit Kugelgraphit" vorgestellt. Mit Blick auf bruchmechanische Sicherheitsbewertungen in der Kerntechnik werden Stähle momentan mit dem deterministischen ASME-Referenzkurvenkonzept, ergänzt durch das probabilistische Master Curve-Konzept nach ASTM E1921, bewertet. Das Master Curve-Konzept wird bereits für die Bewertung von ferritischen Schmiedestahlbehältern verwendet. Bewertungsmethoden für ferritisches Gusseisen mit Kugelgraphit sind im Moment unvollständig. Normen wie die nationale BDG-Richtlinie P300 oder der internationale ASME-Code, Sect. III, Div. 3, WC-2330 decken Sprödbruch nicht ausreichend ab. Die Verwendung des Master Curve-Konzepts für ferritisches Gusseisen mit Kugelgraphit würde eine bruchmechanische Bewertung via einer KJc,d Verteilung erlauben und gleichzeitig Größeneffekte und einen Temperaturbereich von 100 K berücksichtigen. T2 - GRS-Projektstatusgespräch 2023 CY - Karlsruhe, Germany DA - 06.11.2023 KW - Dynamische Bruchzähigkeit KW - Sprödbruch KW - Gusseisen mit Kugelgraphit KW - Master Curve PY - 2023 AN - OPUS4-59060 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mayer, Uwe T1 - Untersuchung des Master Curve-Konzeptes für ferritisches Gusseisen mit Kugelgraphit N2 - In dem Vortrag werden der Forschungsansatz, die Ziele, das Untersuchungsprogramm und die erwarteten Ergebnisse des BMUVForschungsvorhabens MCGUSS "Untersuchung des Master Curve-Konzeptes für ferritisches Gusseisen mit Kugelgraphit" vorgestellt. Mit Blick auf bruchmechanische Sicherheitsbewertungen in der Kerntechnik werden Stähle momentan mit dem deterministischen ASME Referenzkurvenkonzept, ergänzt durch das probabilistische Master Curve-Konzept nach ASTM E1921, bewertet. Das Master Curve-Konzept wird bereits für die Bewertung von ferritischen Schmiedestahlbehältern verwendet. Bewertungsmethoden für ferritisches Gusseisen mit Kugelgraphit sind im Moment unvollständig. Normen wie die nationale BDG-Richtlinie P300 oder der internationale ASME-Code, Sect. III, Div. 3, WC-2330 decken Sprödbruch nicht ausreichend ab. Die Verwendung des Master Curve-Konzepts für ferritisches Gusseisen mit Kugelgraphit würde eine bruchmechanische Bewertung via einer KJc,d Verteilung erlauben und gleichzeitig Größeneffekte und einen Temperaturbereich von 100 K berücksichtigen. T2 - GRS-Projektstatusgespräch 2023 CY - Karlsruhe, Germany DA - 06.11.2023 KW - Dynamische Bruchzähigkeit KW - Master Curve KW - Gusseisen mit Kugelgraphit KW - Sprödbruch PY - 2023 AN - OPUS4-59061 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Holzwarth, M. T1 - First results for the modification of the master curve concept for ferritic ductile cast iron N2 - Within the scope of fracture mechanics safety, ferritic ductile cast iron (DCI) does currently not have an established and validated method to determine and assess dynamic fracture toughness values in the ductile-to-brittle transition regime. For this reason, the applicability of the fracture mechanics Master Curve concept according to ASTM E1921 to DCI is being investigated in a joint research project between MPA Stuttgart and BAM Berlin. To investigate the applicability of the Master Curve concept for DCI, a DCI material of grade GJS-400 has been procured via a detailed manufacturing specification. From this material test specimens of various geometries and sizes (Tensile, Charpy-V, Pellini, SE(B)10, SE(B)25, SE(B)140, DC(T)9, C(T)25 and C(T)50) were produced. In total, about 500 test specimens will be tested to investigate and validate the Master Curve Concept as well as other assumptions (e.g. size effects, Weakest-Link, Weibull distribution) for DCI. While the whole project has not yet concluded, several work packages have yet been completed. Selected test results using C(T)25 specimens are presented. T2 - European Conference on Fracture 2024 CY - Zagreb, Croatia DA - 26.08.2024 KW - Dynamic fracture toughness KW - Ductile cast iron KW - Master curve PY - 2024 AN - OPUS4-61451 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Baer, Wolfram A1 - Ohm, Katrin A1 - Holzwarth, Marcel A1 - Mayer, Uwe T1 - Master Curve-Auswertungen und fraktographische Analysen zum Bruchmechanismus – neue Ergebnisse zur Untersuchung des Master Curve Konzepts für ferritisches Gusseisen mit Kugelgraphit bei dynamischer Beanspruchung (Projekt MCGUSS) N2 - In diesem Beitrag werden erste Master Curve (MC)-Auswertungen und fraktographische Analysen zum Bruchmechanismus aus dem laufenden Kooperationsprojekt MCGUSS zwischen der BAM Berlin und der MPA Stuttgart diskutiert. Für zwei SE(B)140-Großprobenversuchsserien mit je 6-8 Versuchen bei -40 °C bzw. -60 °C und Belastungsraten von 5-8x10^4 MPa√m/s wurden Referenztemperaturen T0 bestimmt. Ergänzt wird dies für erste Versuchsreihen an SE(B)25-Kleinproben, die bei -60 °C und Belastungsraten von ca. 2x10^5 MPa√m/s geprüft wurden. An ausgewählten Bruchflächen dieser Versuche wurden detaillierte fraktographische REM-Analysen vorgenommen. Im Vordergrund stand die Charakterisierung des Bruchmechanismus in Abhängigkeit von den Einflussfaktoren Temperatur und Probengröße. In Richtung der Zähigkeitstieflage werden die Analysen komplettiert durch die Ergebnisse von zwei SE(B)140-Großprobenversuchen bei -100 °C bzw. -140 °C und Belastungsraten von ca. 5-8x10^4 MPa√m/s. T2 - 57. Tagung des DVM-Arbeitskreises Bruchmechanik und Bauteilsicherheit CY - Köln, Germany DA - 18.02.2025 KW - Dynamische Beanspruchung KW - Bruchmechanik KW - Master Curve-Konzept KW - Gusseisen mit Kugelgraphit PY - 2025 DO - https://doi.org/10.48447/BR-2025-467 SP - 113 EP - 122 PB - DVM-Verlag CY - Berlin AN - OPUS4-62554 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Holzwarth, Marcel A1 - Baer, Wolfram A1 - Mayer, Uwe A1 - Weihe, Stephan T1 - Investigation of the Master Curve Concept for Ferritic Ductile Cast iron N2 - Within fracture mechanics safety assessment for steels in nuclear technology, the probabilistic master curve (MC) concept according to ASTM E1921 is currently used for quasi-static loading conditions as a supplement to the established deterministic ASME reference curve concept. However, for ductile cast iron (DCI), a systematic review of potential modifications to the assumptions and the procedure according to ASTM E1921 and an associated validation are still lacking. For this reason, the application of the fracture mechanics MC concept to ferritic ductile cast iron is being investigated in a recently started joint research project between MPA Stuttgart and BAM Berlin. According to the IAEA guidelines SSG 26, the safety assessment of DCI containers for transport as well as storage of radioactive materials is based on the fracture mechanics criterion of general crack initiation exclusion. Within this context, the focus of the current research project is on the further development of brittle fracture safety assessment methods. Therefore, a methodology shall be established to determine and assess dynamic fracture toughness values of DCI in the ductile-to-brittle transition regime, using samples extracted from a component. For the experimental program, a DCI material will be produced as it is generally used for transport and storage containers. A basic mechanical-technological material characterization consisting of tensile, Charpy and Pellini tests is planned and a comprehensive fracture mechanics test program was compiled covering dynamic testing of DC(T)9, C(T)25, C(T)50, SE(B)10, SE(B)25, and SE(B)140 specimens. Numerical analyses of different specimen geometries and test setups are planned to investigate the influences of stress triaxiality and loading rate. Throughout the experimental program, the microstructure-property relationship will be investigated based on quantitative metallographic and fractographic analyses. Finally, different MC assessment strategies will be considered and modifications will be made if necessary. T2 - 21st International Symposium ASTM/ESIS Symposium on Fatigue and Fracture Mechanics CY - Washington, D.C., USA DA - 08.11.2023 KW - Dynamic Fracture Toughness KW - Cleavage fracture KW - Master Curve Concept KW - Ductile Cast Iron PY - 2023 AN - OPUS4-59063 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Holzwarth, Marcel T1 - Investigation of the Master Curve Concept for Ferritic Ductile Cast Iron N2 - Within fracture mechanics safety assessment for steels in nuclear technology, the probabilistic master curve (MC) concept according to ASTM E1921 is currently used for quasi-static loading conditions as a supplement to the established deterministic ASME reference curve concept. However, for ferritic ductile cast iron (DCI), a systematic review of potential modifications to the assumptions and the procedure according to ASTM E1921 and an associated validation are still lacking. For this reason, the application of the fracture mechanics MC concept to ferritic ductile cast iron is being investigated in a joint research project between MPA Stuttgart and BAM Berlin. According to IAEA SSG-26, the safety assessment of DCI containers for transport as well as storage of radioactive materials is based on the fracture mechanics criterion of general crack initiation exclusion. Within this context, the focus of the research project is on brittle fracture. The goal is the establishment of a methodology to determine and assess dynamic fracture toughness values of DCI in the ductile-to-brittle transition regime, using samples extracted from a component. The experimental program uses a DCI material of grade GJS-400, which is generally used for transport and storage containers of radioactive materials. Firstly, a basic mechanical-technological material characterization will be performed consisting of tensile, Charpy and Pellini tests. Following the material characterization, the loading rate relevant for brittle fracture will be determined using instrumented C(T)25-fracture tests at a temperature of -40°C. To be able to transfer the relevant loading rate to other specimen geometries or sizes, the time-dependent course of the Weibull stress is assessed via numerical analyses. With this information an extensive experimental program consisting of DC(T)9, C(T)25, C(T)50, SE(B)10, SE(B)25 and SE(B)140 specimens is performed. These experimental results will be further supported by numerical and fractographic analyses. The empirical experimental database developed for DCI materials will be used to assess the applicability of the MC concept for DCI materials under dynamic loading. At the current time manufacturing and precracking of test specimens is ongoing. The authors provide first results concerning the mechanical-technological material characterization, the relevant loading rate for brittle fracture determined via C(T)25 tests, and some early results of other specimen types. These experimental results are also supported by preliminary numerical and statistical analyses. T2 - Conference SMiRT27 CY - Yokohama, Japan DA - 04.03.2024 KW - Dynamic fracture toughness KW - Ductile cast iron KW - ASTM E1921 KW - Master curve KW - Brittle fracture PY - 2024 AN - OPUS4-59859 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Holzwarth, Marcel A1 - Mayer, Uwe A1 - Baer, Wolfram A1 - Weihe, Stefan T1 - Investigation of the Master Curve Concept for Ferritic Ductile Cast Iron N2 - Within fracture mechanics safety assessment for steels in nuclear technology, the probabilistic master curve (MC) concept according to ASTM E1921 is currently used for quasi-static loading conditions as a supplement to the established deterministic ASME reference curve concept. However, for ductile cast iron (DCI), a systematic review of potential modifications to the assumptions and the procedure according to ASTM E1921 and an associated validation are still lacking. For this reason, the application of the fracture mechanics MC concept to ferritic ductile cast iron is being investigated in a joint research project between MPA Stuttgart and BAM Berlin. According to Hojo et al. (2008) the MC concept is already in use for the brittle fracture safety assessment of ferritic forged steel containers, which would suggest an extension to ductile cast iron containers. In compliance with IAEA SSG-26, the safety assessment of DCI containers for transport as well as storage of radioactive materials is based on the fracture mechanics criterion of general exclusion of crack initiation. Within this context, the focus of the current research project is on the further development of brittle fracture safety assessment methods. Therefore, a methodology shall be established to determine and assess dynamic fracture toughness values of DCI in the ductile-to-brittle transition regime, using only a low number of small fracture mechanics test specimens extracted from a component. For the experimental program, a DCI material of grade GJS-400 (GGG-40) has been produced as it is generally used for transport and storage containers for nuclear material. A basic mechanical-technological material characterization consisting of tensile, Charpy, and Pellini tests has been planned and a comprehensive fracture mechanics test program was compiled covering dynamic testing of DC(T)9, C(T)25, C(T)50, SE(B)10, SE(B)25, and SE(B)140 specimens at various loading rates and temperatures. The specimen testing is divided between the project partners based on specimen geometry. MPA Stuttgart has been tasked with the testing of the C(T), DC(T) and Pellini specimens, while BAM Berlin was assigned the SE(B), Charpy and tensile tests. These tests allow for the determination of the loading rate relevant for brittle fracture via C(T)25 specimens and an assessment of size effects by transferring the relevant loading rate to other specimen geometries and sizes. Numerical analyses of different specimen geometries and test setups are planned to investigate the influence of stress triaxiality and loading rate. Furthermore, the time-dependent course of the Weibull stress is assessed via these numerical analyses. Throughout the experimental program, the microstructure-property relationship will also be investigated based on quantitative metallographic and fractographic analyses like scanning electron microscope images and metallographic sections. With the acquired experimental database fundamental assumptions of the MC concept, like the weakest link model and the Weibull distribution, will be assessed for the application to DCI. In the end, the applicability of the MC concept will be evaluated and if necessary, modifications to the MC concept for DCI will be proposed. This paper will present the preliminary results of the GJS400 material characterization and the related selection of test specimen extraction points. First results of the C(T)25 and SE(B)140 specimen testing will also be discussed supported by first metallographic analyses. T2 - SMiRT27 Conference CY - Yokohama, Japan DA - 03.03.2024 KW - Ductile Cast iron KW - Dynamic Fracture Toughness KW - Safety Assessment KW - Master Curve Concept PY - 2024 SP - 1 EP - 10 AN - OPUS4-59302 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Holzwarth, Marcel A1 - Baer, Wolfram A1 - Mayer, Uwe A1 - Weihe, Stefan T1 - On the Applicability of the Master Curve Concept for Ductile Cast Iron based on experimental and microstructural results N2 - Based on the state-of-the-art research and regulations, the application of the fracture mechanics master curve (MC) concept to ferritic ductile cast iron (DCI) is being investigated in a joint research project (MCGUSS) between BAM Berlin and MPA Stuttgart. The experimental program included a basic mechanical-technological material characterization consisting of tensile, Charpy and Pellini tests. To determine the relevant loading rate for brittle fracture, instrumented C(T)25 fracture tests were performed at different loading rates at a temperature of -40°C. The relevant loading rates are 5x10^3 MPa√ms-1 and 5x10^4 MPa√ms-1. A series of dynamic fracture tests consisting of DC(T)9, C(T)25 and C(T)50 specimens were performed at MPA. BAM performed corresponding test series with SE(B)10 (pre-cracked Charpy), SE(B)25 and SE(B)140 specimens to cover the influence of specimen geometry. In total about 400 tests were performed during this project. The experimental program is complemented by extensive fractographic and metallographic studies using scanning electron microscopy and cross sectioning, as well as characterizations of the chemical composition of the material and of the morphology and distribution of the graphite particles. KJcd values were evaluated for all C(T)25 specimens and some C(T)50 and DC(T)9 specimens. First Master Curve analyses suggest that modifications on the Master Curve setup will be neccessary for instance changing the coefficient from 0.019 to 0.045. This modification requires further validation and is only one of many possible modifications. The SE(B) specimen results clearly show an inverse size effect. This does not correlate with the weakest link effect attributed to steels which dictates lower fracture toughness values for larger specimens. Due to the presence of graphite particles in the DCI material, it is currently assumed that these particles play a significant role in the failure behavior of DCI materials and the following fracture mechanism is proposed: “Specimen size-dependent arrest of local brittle fracures before global brittle failure by weakest link”. T2 - 9th SEDS Workshop: Safety of Extended Dry Storage, 20.-22. Mai 2025 CY - Garching, Germany DA - 20.05.2025 KW - Statistics KW - Dynamic fracture toughness KW - Ductile cast iron KW - Master curve KW - Safety assessment PY - 2025 SP - 1 EP - 3 AN - OPUS4-63566 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Castells-Gil, Javier A1 - Zhu, Jinjie A1 - Itskou, Ioanna A1 - Wolpert, Emma H. A1 - Hunter, Robert D. A1 - Tidey, Jeremiah P. A1 - Pedersen, Angus A1 - Solvay, Elisa A1 - Tyrrell, Helen A1 - Petit, Camille A1 - Barrio, Jesús T1 - Impact of N-heterocyclic amine modulators on the structure and thermal conversion of a zeolitic imidazole framework N2 - The zeolitic imidazole framework-8 (ZIF-8) is a crystalline porous material that has been widely employed as template to fabricate porous nitrogen-doped carbons with high microporosity via thermal treatment at high temperatures. The properties of the carbon scaffold are influenced by the pore structure and chemical composition of the parent ZIF. However, the narrow pore size distribution and microporous nature from ZIF-8 often results in low mesopore volume, which is crucial for applications such as energy storage and conversion. Here we show that insertion of N-heterocyclic amines can disrupt the structure of ZIF-8 and dramatically impact the chemical composition and pore structure of the nitrogen-doped carbon frameworks obtained after high-temperature pyrolysis. Melamine and 2,4,6-triaminopyrimidine were chosen to modify the ZIF-8 structure owing to their capability to both coordinate metal ions and establish supramolecular interactions. Employing a wide variety of physical characterization techniques we observed that melamine results in the formation of a mixed-phase material comprising ZIF-8, Zn(Ac)6(Mel)2 and crystallized melamine, while 2,4,6-triaminopyrimidine induces the formation of defects, altering the pore structure. Furthermore, the absence of heterocyclic amine in the ZIF-8 synthesis leads to a new crystalline phase, unreported to date. The thermal conversion of the modified ZIFs at 1000 °C leads to nitrogen-doped carbons bearing Zn moieties with increased surface area, mesopore volume and varying degree of defects compared to ZIF-8 derived carbon. This work therefore highlights both the versatility of heterocyclic amines to modify the structure of framework materials as well as their role in tuning pore structure in nitrogen-doped carbons, paving the way to targeted design of high-performance electrodes for energy storage and conversion. KW - Zeolitic imidazole framework KW - Heterocyclic amine KW - Triaminopyrimidine PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639177 DO - https://doi.org/10.1039/D5TA04831A SN - 2050-7488 SP - 1 EP - 13 PB - Royal Society of Chemistry (RSC) AN - OPUS4-63917 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Braga, Daniel S. A1 - Pedersen, Angus A1 - Riyaz, Mohd A1 - Barrio, Jesús A1 - Bagger, Alexander A1 - Neckel, Itamar T. A1 - Mariano, Thiago M. A1 - Winkler, Manuel E. G. A1 - Stephens, Ifan E. L. A1 - Titirici, Maria‐Magdalena A1 - Nagao, Raphael T1 - In situ structural evolution and activity descriptor of atomically dispersed catalysts during nitrate electroreduction N2 - Single‐Atom Catalysts (SAC) have emerged as a promising class of materials for various catalytic applications, including the electrochemical nitrate reduction reaction (eNO3RR) and consequently ammonia production. While the efficiency and selectivity of these materials have been extensively highlighted for the eNO3RR, the in situ evolution to their structure and composition during electrocatalysis is largely unexplored and lacks catalyst design principles. To solve this, we investigated a series of high utilization metal‐nitrogen‐carbon (MNC) SACs (M = Cr, Fe, Co, Ni, and Cu) for eNO3RR. Except for CuNC, which selectively produced nitrite, all catalysts exhibited Faradaic efficiencies (FE) for ammonia exceeding 50%. NiNC demonstrated the highest performance (FE of 78.0 ± 2.9% at −0.4 V versus reversible hydrogen electrode (RHE) at pH 13 and maximum ammonia production rate of 615.7 ± 176.5 µmol·h−1·, corresponding to an energy efficiency of 15.1 ± 1.4% at −0.6 VRHE), followed by CoNC. In situ Synchrotron X‐ray fluorescence (SXRF) mapping at various cathodic potentials (from open circuit potential to 0.0 VRHE and then −0.6 VRHE at 100 mV steps) revealed significant mobility of Ni within the carbon matrix, leading to the formation of metallic clusters from 0.0 VRHE. Similar in situ metal clustering is observed for CoNC. Structure‐activity plots are generated from both MNC literature and results obtained here, finding a clear trend between OH binding energy and turnover frequency, with the high activity of NiNC and CoNC in this work explained by their stronger OH binding in the metallic structure compared to their SAC coordination. This work therefore, reveals the structure‐activity‐stability of MNCs for eNO3RR and provides a simple descriptor for identifying highly active eNO3RR catalysts and their in situ structural evolution. KW - Single atom KW - Nitrate reduction KW - Structure-activity-selectivity KW - In situ PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-640353 DO - https://doi.org/10.1002/advs.202510282 SN - 2198-3844 VL - 12 IS - 39 SP - 1 EP - 14 PB - Wiley-VCH CY - Weinheim AN - OPUS4-64035 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Butz, Adam T1 - Experimental and analytical investigation of notched components of a Nickel based superalloy under high temperature cyclic loading N2 - While the increase in use of renewable energy sources is a necessity in times of climate change the use of gas turbines as back-up requires them to be run in a much more flexible manner in order to compensate for side effects like sudden fluctuations of energy generation. The significant changes of stress and temperature levels in turbine blades due to start-up and shut down can cause crack initiation and growth in the blades‘ alloy. The aim of this research project is to identify a model for lifetime prediction for gas turbine components made of a Nickel base superalloy under high temperature with a Focus on stress concentration points such as cooling holes. T2 - HIDA-7 Conference on Life/Crack Assessment & Failures in Industrial Structures, UK CY - Portsmouth, UK DA - 15.05.2017 KW - LCF KW - Gas turbine KW - Service life model PY - 2017 AN - OPUS4-42274 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Morcillo, Dalia A1 - Winckelmann, Alexander A1 - Oelze, Marcus A1 - Leonhardt, Robert A1 - Schmidt, Anita A1 - Richter, Silke A1 - Recknagel, Sebastian A1 - Vogl, Jochen A1 - Panne, Ulrich A1 - Abad Andrade, Carlos Enrique T1 - Exploring Age-Induced Lithium Isotope Fractionation in Lithium-Ion Batteries using Microwave-Induced Cold Nitrogen Plasma Mass Spectrometry N2 - This study explores Microwave-Inductively Coupled Atmospheric-pressure Plasma Mass Spectrometry (MICAP-MS) as a cost-effective alternative to Multi-Collector Inductively Coupled Plasma Mass Spectrometry (MC-ICP-MS) for analyzing lithium isotopic composition in lithium-ion batteries (LIBs). We investigate the performance of MICAP-MS in measuring Li isotope ratios in new and aged commercial lithium cobalt oxide (LCO) batteries. Our results show that MICAP-MS, operating under cold plasma conditions at 800 W with an 8 mm torch position, achieves results metrologically compatible with MC-ICP-MS, with a precision ranging from 0.6‰ to 3.4‰ for δ7Li values. MICAP-MS benefits from a dielectric resonator for uniform plasma, better ion velocity control, and higher energy efficiency. Optimal settings were identified with dwell times of 10 ms for 6Li and 1 ms for 7Li. The study of LIBs revealed that 6Li migrates towards the anode over multiple charge–discharge cycles, causing 7Li to accumulate in the cathode, a fractionation effect that becomes more pronounced with prolonged cycling. MICAP-MS provides a cost-effective, precise alternative to MC-ICP-MS, with lower operational costs and enhanced portability, advancing the study of isotopic fractionation and aging in lithium-ion batteries. KW - MICAP-MS KW - Lithium KW - Battery aging KW - Lithium isotopes KW - Nitrogen plasma KW - Isotope fractionation KW - lithium cobalt oxide KW - LCO PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-643777 DO - https://doi.org/10.1039/d4ja00324a SN - 0267-9477 SP - 1 EP - 11 PB - Royal Society of Chemistry (RSC) AN - OPUS4-64377 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Abad Andrade, Carlos Enrique T1 - Data-Driven Spectrochemical Sensing for Elemental and Isotopic Analysis—from Energy Systems to Biomedicine N2 - High-resolution optical spectrometers generate spectra containing tens of thousands of data points per sample. Picometre-scale isotope shifts, matrix-induced line broadening, and strong inter-feature correlations render classical peak fitting unreliable. Current analytical challenges, therefore, require rigorous algorithms able to expose latent structure, quantify uncertainty, and remain chemically interpretable. The research program presented in this lecture integrates state-of-the-art spectrochemical instrumentation with mathematically disciplined data models. Principal Component Analysis and Partial Least Squares provide chemically meaningful latent variables, while gradient-boosted decision trees or deep neural networks (ANNDL) capture residual non-linearity without sacrificing traceability. All models are trained on isotope-enriched or synthetically generated spectra and distributed with full validation workflows. Two research areas illustrate this strategy: (1) Isotopic analytics for materials, environment, and medicine. (2) Data-fusion diagnostics for battery ageing and failure. T2 - Temple University: Mechanical Engineering Transformative Science and Technology Engineering Lecture Series CY - Philadelphia, PA, USA DA - 02.10.2025 KW - Isotope KW - Data analysis KW - Machine learning KW - Elemental analysis KW - Battery PY - 2025 AN - OPUS4-64877 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -