TY - JOUR A1 - Beygi Nasrabadi, Hossein A1 - Bauer, Felix A1 - Uhlemann, Patrick A1 - Thärig, Steffen A1 - Rehmer, Birgit A1 - Skrotzki, Birgit T1 - Mechanical testing dataset of cast copper alloys for the purpose of digitalization N2 - This data article presents a set of primary, analyzed, and digitalized mechanical testing datasets for nine copper alloys. The mechanical testing methods including the Brinell and Vickers hardness, tensile, stress relaxation, and low-cycle fatigue (LCF) testing were performed according to the DIN/ISO standards. The obtained primary testing data (84 files) mainly contain the raw measured data along with the testing metadata of the processes, materials, and testing machines. Five secondary datasets were also provided for each testing method by collecting the main meta- and measurement data from the primary data and the outputs of data analyses. These datasets give materials scientists beneficial data for comparative material selection analyses by clarifying the wide range of mechanical properties of copper alloys, including Brinell and Vickers hardness, yield and tensile strengths, elongation, reduction of area, relaxed and residual stresses, and LCF fatigue life. Furthermore, both the primary and secondary datasets were digitalized by the approach introduced in the research article entitled “Toward a digital materials mechanical testing lab” [1]. The resulting open-linked data are the machine-processable semantic descriptions of data and their generation processes and can be easily queried by semantic searches to enable advanced data-driven materials research. KW - FAIR principles KW - Hardness KW - Low-Cycle Fatigue (LCF) KW - Tensile testing KW - Stress relaxation PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-605005 DO - https://doi.org/10.1016/j.dib.2024.110687 SN - 2352-3409 SP - 1 EP - 15 PB - Elsevier BV AN - OPUS4-60500 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Han, Ying A1 - Kruse, Julius A1 - Rosalie, Julian A1 - Radners, J. A1 - von Hartrott, P. A1 - Skrotzki, Birgit T1 - Influence of mean stress and overaging on fatigue life of aluminum alloy EN AW-2618A N2 - Fatigue tests were performed on the forged aluminum alloy EN AW-2618A in the T61 state. Different stress ratios (R = -1, R = 0.1) were selected to study the influence of mean stress on fatigue life. Two overaged states (10 h/230 ◦C, 1000 h/230 ◦C) were also tested to investigate the influence of overaging on fatigue life. Transmission electron microscopy (TEM) was used to characterize the precipitates (S-phase), which are mainly responsible for the strength of the alloy. A fractographic analysis was also performed to determine the failure mode. Overaging reduces the fatigue life compared to the T61 state. The longer the aging time, the lower the fatigue resistance. The reason is the decrease in (yield) strength, which correlates with the radius of the S-phase: the precipitate radius increases by a factor of approximately two for the overaged states compared to the initial state. The analysis of the fracture surfaces showed crack initiation occurs predominantly on the outer surface and is associated with the primary phases. KW - Aluminum alloys KW - Aging KW - Fatigue KW - Microstructure KW - Electron microscopy KW - S-Phase PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-583708 DO - https://doi.org/10.1016/j.msea.2023.145660 SN - 0921-5093 VL - 886 SP - 1 EP - 10 PB - Elsevier B.V. AN - OPUS4-58370 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rehmer, Birgit A1 - Bayram, Faruk A1 - Ávila Calderón, Luis A1 - Mohr, Gunther A1 - Skrotzki, Birgit T1 - Elastic modulus data for additively and conventionally manufactured variants of Ti-6Al-4V, IN718 and AISI 316 L N2 - This article reports temperature-dependent elastic properties (Young’s modulus, shear modulus) of three alloys measured by the dynamic resonance method. The alloys Ti-6Al-4V, Inconel IN718, and AISI 316 L were each investigated in a variant produced by an additive manufacturing processing route and by a conventional manufacturing processing route. The datasets include information on processing routes and parameters, heat treatments, grain size, specimen dimensions, and weight, as well as Young’s and shear modulus along with their measurement uncertainty. The process routes and methods are described in detail. The datasets were generated in an accredited testing lab, audited as BAM reference data, and are hosted in the open data repository Zenodo. Possible data usages include the verification of the correctness of the test setup via Young’s modulus comparison in low-cycle fatigue (LCF) or thermo-mechanical fatigue (TMF) testing campaigns, the design auf VHCF specimens and the use as input data for simulation purposes. KW - Elastic modulus KW - Young's modulus KW - Shear modulus KW - Additive manufacturing KW - AISI 316L KW - IN 718 KW - Ti-6Al-4V KW - Reference data KW - Temperature dependence PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-579716 DO - https://doi.org/10.1038/s41597-023-02387-6 VL - 10 IS - 1 SP - 1 EP - 9 PB - Springer Nature AN - OPUS4-57971 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sonntag, Nadja A1 - Jürgens, Maria A1 - Uhlemann, Patrick A1 - Skrotzki, Birgit A1 - Olbricht, Jürgen T1 - Experimental data from service-like creep-fatigue experiments on grade P92 steel N2 - This article refers to the research article entitled “Creep-Fatigue of P92 in Service-Like Tests with Combined Stress- and Strain-Controlled Dwell Times” [1]. It presents experimental mechanical data from complex service-like creep-fatigue experiments performed isothermally at 620 °C and a low strain amplitude of 0.2 % on tempered martensite-ferritic grade P92 steel. The data sets in text file format provide cyclic deformation (min. and max. stresses) and the total (hysteresis) data of all recorded fatigue cycles for three different creep-fatigue experiments: 1) a standard relaxation fatigue (RF) test with symmetrical dwell times of three minutes introduced at minimum and maximum strain, 2) a fully strain-controlled service-like relaxation (SLR) test combining these three-minute peak strain dwells with a 30-minute dwell in between at zero strain, and 3) a partly stress-controlled service-like creep (SLC) test combining the three-minute peak strain dwells with 30-minute dwells at constant stress. Such service-like (SL) tests with additional long-term stress- and strain-controlled dwell times are non-standard, rare, and expensive, making these data very valuable. They may be used to approximate cyclic softening in the technically relevant range, for the design of complex SL experiments, or for detailed analyses of stress-strain hystereses (e.g., for stress or strain partitioning methods, for the determination of hysteresis energies (work), inelastic strain components, etc.). In addition, the latter analyses may supply important input for advanced parametric lifetime modeling of components under creep-fatigue loading or model calibration parameters. KW - Tempered martensite-ferritic steel KW - Creep KW - Stress relaxation KW - Creep-fatigue KW - Dwell times PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-578407 DO - https://doi.org/10.1016/j.dib.2023.109333 SN - 2352-3409 VL - 49 SP - 1 EP - 9 PB - Elsevier Inc. AN - OPUS4-57840 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kühn, Hans-Joachim A1 - Rehmer, Birgit A1 - Skrotzki, Birgit T1 - Thermomechanical fatigue of heat-resistant austenitic cast iron EN-GJSA-XNiSiCr35-5-2 (Ni-Resist D-5S) N2 - TMF tests were carried out on EN-GJSA-XNiSiCr35-5-2 at constant minimum temperature (400 °C) and varying maximum temperatures (Tmax = 700 °C, 800 °C, 900 °C) with hold times of 180 s at Tmax and two phase angles (in-phase (IP), 180° out-of-phase (OP)). The results showed a comparable strength under OP- and IP-TMF loading. At Tmax = 700 °C and 900 °C, the lifetime in IP-tests was slightly longer than that of OP-tests, while it is vice versa at Tmax = 800 °C. The IP-tests at Tmax = 900 °C showed a similar lifetime as OP-tests at Tmax = 700 °C and 800 °C, which was unexpected for such a high testing temperature. All IP-tests at Tmax = 900 °C showed a continuous cyclic softening from the beginning on, which was different from all other testing conditions. Complementary metallographic investigations indicated that under this test condition, intergranular creep damage is present in the volume of the test pieces. T2 - 3rd International Workshop on Thermo-Mechanical Fatigue (TMF-Workshop 2016) CY - Berlin, Germany DA - 27.04.2016 KW - Cast iron KW - Cracks KW - Cyclic softening KW - Microscopy KW - Thermomechanical fatigue PY - 2017 DO - https://doi.org/10.1016/j.ijfatigue.2017.01.009 SN - 0142-1123 SN - 1879-3452 VL - 99 IS - 2 (Special issue: Recent developments in thermo-mechanical fatigue) SP - 295 EP - 302 PB - Elsevier CY - Oxford AN - OPUS4-39680 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jentzsch, Stefan A1 - Stock, Daniel A1 - Häcker, Ralf A1 - Skrotzki, Birgit A1 - Darvishi Kamachali, Reza A1 - Klingbeil, Dietmar A1 - Kindrachuk, Vitaliy T1 - Shear Band Formation with Split Hopkinson Bar Experiments N2 - The essence of dynamic failure is closely linked to dramatic shear deformations which often lead to the formation of adiabatic shear bands (ASB). Under high loading velocities and the subsequent rapid temperature increase, the localization of shear strain is crucial in view of safety issues of systems in mechanical and aircraft engineering, especially with respect to fast rotating components and diverse crash scenarios. In this research, we perform high speed impact tests at the split Hopkinson pressure bar (SHPB) setup and use particular hat-shaped specimen geometries that resemble the stresses and failure conditions at the component level. In the first step, we specify a notched specimen geometry using finite element (FE) simulations to ensure pure shear. Further, quasi-static compressive tests and a series of impact tests at high strain rates of 10^3-10^4 s^-1 are conducted on specimens manufactured from a fine-grain structural steel with the properties of S355. Optical microscopy and electron backscatter diffraction (EBSD) of the sheared zones unveil significant localization to maximal shear strains of about 0.9 accompanied by grain refinement by factors 5 to 14. The displacements across the surface of the specimens are captured with subset-based local digital image correlation (DIC) during the impact time, and serve as an objective to validate a viscoplastic constitutive relationship. More precisely, the deformation distribution is accurately reproduced by the widely recognized Johnson-Cook (JC) model, which features an enhanced description of damage evolution. Thus, combining experimental and characterization techniques, continuum mechanics and reasonable optimization strategies for the identification of model parameters provides an efficient approach for comprehensive insights into the strain localization behaviour and its impact on the mechanical performance of S355 under extreme strain rates and deformations. KW - Adiabatic shear bands KW - Finite element analysis KW - Viscoplastic material modelling KW - Split Hopkinson pressure bar KW - Hat-shaped specimen KW - Johnson–Cook parameter identification PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613339 DO - https://doi.org/10.1016/j.ijmecsci.2024.109749 VL - 284 SP - 1 EP - 14 PB - Elsevier BV AN - OPUS4-61333 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Eisenbart, Miriam A1 - Hanke, Thomas A1 - Bauer, Felix A1 - Beygi Nasrabadi, Hossein A1 - Junghanns, Kurt A1 - Dziwis, Gordian A1 - Tikana, Ladji A1 - Parvez, Ashak Mahmud A1 - van den Boogaart, Karl Gerald A1 - Sajjad, Mohsin A1 - Friedmann, Valerie A1 - Preußner, Johannes A1 - Ramakrishnan, Anantha Narayanan A1 - Klengel, Sandy A1 - Meyer, Lars‐Peter A1 - Martin, Michael A1 - Klotz, Ulrich Ernst A1 - Skrotzki, Birgit A1 - Weber, Matthias T1 - KupferDigital: Ontology‐Based Digital Representation for the Copper Life Cycle N2 - The copper life cycle comprises numerous stages from the alloy production to the manufacturing and usage of engineered parts until recycling. At each step, valuable data are generated and stored; some are transferred to the subsequent stations. A thorough understanding of the materials’ behavior during manufacturing processes or throughout their product lifetime is highly dependent on a reliable data transfer. If, for example, a failure occurs during the service life, information about the manufacturing route can be of decisive importance for detecting the root cause of the failure. Additionally, the life cycle assessment hinges on the availability of data. Recording and storing interoperable structured data is, therefore, a thriving research field with huge implications for the economic strength of the manufacturing industry. In the KupferDigital project, it is demonstrated how an ontology‐based data space can be utilized not only as an innovative method for storing and providing interoperable life cycle data but also as a means to enable automated data analysis and evaluation, leading to new insights and the creation of new knowledge using semantic data and technologies. This work illustrates how data recorded at different research facilities can be integrated into one single data space, allowing queries across heterogeneous sources. KW - Copper Alloy KW - Ontology KW - Digitalization KW - Data Space KW - Semantic Representation PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630213 SN - 1527-2648 DO - https://doi.org/10.1002/adem.202401735 VL - 27 IS - 8 SP - 1 EP - 29 PB - Wiley AN - OPUS4-63021 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nies, Daniel A1 - Pulz, Robert A1 - Glaubitz, Steffen A1 - Finn, Monika A1 - Rehmer, Birgit A1 - Skrotzki, Birgit T1 - Testing of thermal barrier coatings by laser excitation N2 - Thermal barrier coatings (TBCs) are used to increase the operating temperature of land-, sea-, or air-based turbines. As failure of the coating may result in serious damage of the turbine, reliable estimation of the lifetime is essential. Most experiments to assess the lifetime or to determine parameters for simulations of the behavior of TBCs are done by burner-rig-tests, where the operating conditions are simulated by cyclic heating of the surface and cooling of the backside of a coated sample. In this work a possibility is presented to do comparable experiments by heating the surface with laser irradiation instead of a burner. For this purpose a Nd:YAG-laser with a maximum output power of 1?kW and a wavelength of 1064?nm is used. The laser spot can be moved by integrated optics across the sample surface to achieve homogeneous heating of the coating. Cooling of the backside is done by air. The temperature of the sample surface is determined by an infrared-camera which also enables the possibility to detect failures in the coating via thermography. Additionally, acoustic sensors attached to the sample holder are used to detect failures in the sample. The investigated ceramic material (yttria stabilized zirconia) has a very low absorption coefficient at the used laser wavelength. Therefore, a pre-treatment of the samples was needed to increase the absorption coefficient to be able to heat up the samples. In this paper, the experimental setup and first experimental results are presented. KW - Thermal barrier coating (TBC) KW - Yttria stabilized zirconia KW - Laser irradiation KW - Acoustic emission KW - Thermography PY - 2010 DO - https://doi.org/10.1002/adem.201000212 SN - 1438-1656 VL - 12 IS - 12 SP - 1224 EP - 1229 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-22896 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Olbricht, Jürgen A1 - Bismarck, Marc A1 - Skrotzki, Birgit T1 - Characterization of the creep properties of heat resistant 9-12% chromium steels by miniature specimen testing N2 - A miniature specimen geometry is presented that allows to extract small samples for tensile creep tests directly from critical components of steam generators in power plants like e.g. superheater tubes. In this way, material can be tested which has been subjected to the full processing chain of the component. The specimens then exhibit all microstructural modifications that are present in the component after the shaping process and heat treatment, and representative mechanical properties are determined. Similarly, specimens can be extracted from pre-corroded test pieces or used components after service to determine the impact of complex aging/loading/oxidation conditions during service on the mechanical properties of the material. The applicability of the miniature specimen test method is demonstrated in a comparative creep study involving standard and miniature specimens of P91 tempered martensite ferritic steel. Test results indicate satisfactory accuracy/repeatability of the method. Comparison with large scale specimen data reveals an influence of specimen size on the obtained creep behavior. These size effects need to be considered for a correct interpretation of results from miniature specimen creep tests. KW - Fossil fuel power plants KW - Creep testing KW - Miniature specimen KW - Size effects KW - Tempered martensite ferritic steels KW - P91 PY - 2013 DO - https://doi.org/10.1016/j.msea.2013.07.067 SN - 0921-5093 SN - 1873-4936 VL - 585 SP - 335 EP - 342 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-29080 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jürgens, Maria A1 - Sonntag, Nadja A1 - Olbricht, Jürgen A1 - Fedelich, Bernard A1 - Skrotzki, Birgit T1 - The effect of dwell times on the thermomechanical fatigue life performance of grade P92 steel at intermediate and low strain amplitudes N2 - Results of an extended TMF test program on grade P92 steel in the temperature range of 620 °C - 300 °C, comprising in-phase (IP) and out-of-phase (OP) tests, partly performed with symmetric dwells at Tmax/Tmin, are presented. In contrast to previous studies, the low-strain regime is also illuminated, which approaches flexible operation in a power plant with start/stop cycles. At all strain amplitudes, the material performance is characterized by continuous cyclic softening, which is retarded in tests at lower strains but reaches similar magnitudes in the course of testing. In the investigated temperature range, the phase angle does not affect fatigue life in continuous experiments, whereas the IP condition is more detrimental in tests with dwells. Fractographic analyses indicate creep-dominated and fatigue-dominated damage for IP and OP, respectively. Analyses of the (micro)hardness distribution in the tested specimens suggest an enhanced microstructural softening in tests with dwell times for the low- but not for the high-strain regime. To rationalize the obtained fatigue data, the fracture-mechanics-based D_TMF concept, which was developed for TMF life assessment of ductile alloys, was applied. It is found that the D_TMF parameter correlates well with the measured fatigue lives, suggesting that subcritical growth of cracks (with sizes from a few microns to a few millimeters) governs failure in the investigated range of strain amplitudes. KW - 9-12%Cr steel KW - Thermomechanical fatigue KW - Symmetric dwell periods KW - Low strain KW - Parametric modeling PY - 2021 DO - https://doi.org/10.1016/j.msea.2020.140593 VL - 805 SP - 140593 PB - Elsevier B.V. AN - OPUS4-52374 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ulbricht, Alexander A1 - Ávila Calderón, Luis A1 - Sommer, Konstantin A1 - Mohr, Gunther A1 - Evans, Alexander A1 - Skrotzki, Birgit A1 - Bruno, Giovanni T1 - Evolution of Creep Damage of 316L Produced by Laser Powder Bed Fusion N2 - The damage mechanisms of metallic components produced by process laser powder bed fusion differ significantly from those typically observed in conventionally manufactured variants of the same alloy. This is due to the unique microstructures of additively manufactured materials. Herein, the focus is on the study of the evolution of creep damage in stainless steel 316L specimens produced by laser powder bed fusion. X-ray computed tomography is used to unravel the influence of the process-specific microstructure from the influence of the initial void distribution on creep damage mechanisms. The void distribution of two specimens tested at 600 °C and 650 °C is analyzed before a creep test, after an interruption, and after fracture. The results indicate that the formation of damage is not connected to the initial void distribution. Instead, damage accumulation at grain boundaries resulting from intergranular cracking is observed. KW - Creep KW - Computed Tomography KW - PBF-LB/M/316L KW - Laser Powder Bed Fusion KW - Microstructure KW - AISI 316L KW - Additive Manufacturing PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-574127 DO - https://doi.org/10.1002/adem.202201581 SP - 1 EP - 9 PB - Wiley-VCH GmbH CY - Weinheim AN - OPUS4-57412 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schilling, Markus A1 - Bayerlein, Bernd A1 - von Hartrott, Philipp A1 - Waitelonis, Jörg A1 - Birkholz, Henk A1 - Portella, Pedro Dolabella A1 - Skrotzki, Birgit T1 - FAIR and Structured Data: A Domain Ontology Aligned with Standard‐Compliant Tensile Testing N2 - The digitalization of materials science and engineering (MSE) is currently leading to remarkable advancements in materials research, design, and optimization, fueled by computer‐driven simulations, artificial intelligence, and machine learning. While these developments promise to accelerate materials innovation, challenges in quality assurance, data interoperability, and data management have to be addressed. In response, the adoption of semantic web technologies has emerged as a powerful solution in MSE. Ontologies provide structured and machine‐actionable knowledge representations that enable data integration, harmonization, and improved research collaboration. This study focuses on the tensile test ontology (TTO), which semantically represents the mechanical tensile test method and is developed within the project Plattform MaterialDigital (PMD) in connection with the PMD Core Ontology. Based on ISO 6892‐1, the test standard‐compliant TTO offers a structured vocabulary for tensile test data, ensuring data interoperability, transparency, and reproducibility. By categorizing measurement data and metadata, it facilitates comprehensive data analysis, interpretation, and systematic search in databases. The path from developing an ontology in accordance with an associated test standard, converting selected tensile test data into the interoperable resource description framework format, up to connecting the ontology and data is presented. Such a semantic connection using a data mapping procedure leads to an enhanced ability of querying. The TTO provides a valuable resource for materials researchers and engineers, promoting data and metadata standardization and sharing. Its usage ensures the generation of finable, accessible, interoperable, and reusable data while maintaining both human and machine actionability. KW - Data Interoperability KW - Domain Ontology Development KW - FAIR Data Management KW - Knowledge Representation KW - Tensile Test Ontology KW - Semantic Web Technologies PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-598142 DO - https://doi.org/10.1002/adem.202400138 SN - 1438-1656 SP - 1 EP - 19 PB - Wiley VHC-Verlag AN - OPUS4-59814 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pulz, Robert A1 - Rehmer, Birgit A1 - Schneider, G.A. A1 - Skrotzki, Birgit T1 - Thermal shock study on different advanced ceramics by laser irradiation in different media N2 - The thermal shock behavior of three commercial-advanced ceramics (SSiC, MgO–PSZ, Al2O3) is characterized in air and vacuum applying a laser thermal shock. The available testing system permits the reproducible setting of defined temperature profiles in thin disks and allows a heating-up thermal shock in various media. Due to the accurate determination of the time- and space-resolved temperature distribution, the local stress state can be calculated as a function of time. It is shown that the thermal shock strength is highest for SSiC and lowest in Al2O3 with MgO–PSZ in between. The approach presented in this work allows quantifying the stress state at failure in terms of tangential tensile stress. The investigated environment does not affect the thermal shock resistance under the studied experimental conditions. KW - Laser-thermal shock KW - Advanced ceramic KW - Stress distribution KW - Thermal shock stress KW - Weibull statistics PY - 2016 UR - http://onlinelibrary.wiley.com/doi/10.1002/adem.201500162/full DO - https://doi.org/10.1002/adem.201500162 SN - 1438-1656 VL - 18 IS - 1 SP - 132 EP - 140 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-33456 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Brookes, Stephen-Peter A1 - Kühn, Hans-Joachim A1 - Skrotzki, Birgit A1 - Klingelhöffer, Hellmuth A1 - Sievert, Rainer A1 - Pfetzing, J. A1 - Peter, D. A1 - Eggeler, G. T1 - Axial-torsional thermomechanical fatigue of a near-gamma TiAl-alloy N2 - The uniaxial, torsional and axial-torsional thermomechanical fatigue (TMF) behavior of the near-γ TiAl-alloy TNB-V5 was investigated. TMF tests were performed at 400-800 °C with mechanical strain amplitudes ranging from 0.15% to 0.7%. The tests were conducted thermomechanically in-phase (IP) and out-of-phase (OP). For the same lifetimes, uniaxial IP tests required the highest strain amplitudes, while OP test conditions were most damaging and needed the lowest strain amplitudes. The Mises equivalent mechanical strain amplitudes of pure torsional tests were found in between uniaxial in-phase and out-of-phase tests for the same lifetimes. The non-proportional multiaxial out-of-phase test showed a lower lifetime at the same equivalent mechanical strain amplitude compared to the other types of tests. The microstructure has been characterized applying electron microscopy and microstructural parameters such as fraction of twinned grains, grain size, lamellar distance and dislocation density have been quantified. KW - Gamma titanium aluminide KW - TNB-V5 KW - Thermomechanical fatigue (TMF) KW - Axial-torsional loading KW - Microstructure PY - 2010 DO - https://doi.org/10.1016/j.msea.2010.03.073 SN - 0921-5093 SN - 1873-4936 VL - 527 IS - 16-17 SP - 3829 EP - 3839 PB - Elsevier CY - Amsterdam AN - OPUS4-21289 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pulz, Robert A1 - Rehmer, Birgit A1 - Skrotzki, Birgit T1 - Pyrometric temperature measurement of ceramic thermal shock samples N2 - The determination of critical failure parameters during thermal shock requires a time and space resolved temperature measurement of the sample. High frequency pyrometry is a suitable technique for such a measurement task, which usually requires the knowledge of the optical properties of the investigated material. Another challenge is the infrared transparency of materials to be checked in the wavelength range of the pyrometer. The thermal shock disks are very thin, due to the need of homogeneous temperature distribution and to maintain a two-dimensional problem. To allow a pyrometric temperature measurement a universal calibration method for high frequency infrared cameras has been developed. Pyrometry in various media was demanded, as well as the estimation of optical properties (reflection, transmittance and emission) for the selected ceramics to be tested. KW - Temperature measurement KW - Ceramics KW - Emission coefficient KW - Radiation thermometry KW - Thermal shock PY - 2011 DO - https://doi.org/10.1016/j.measurement.2010.09.050 SN - 0263-2241 SN - 1873-412X VL - 44 IS - 1 SP - 259 EP - 266 PB - Elsevier Ltd. CY - London AN - OPUS4-22474 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bhadeliya, Ashok A1 - Rehmer, Birgit A1 - Fedelich, Bernard A1 - Jokisch, T. A1 - Skrotzki, Birgit A1 - Olbricht, Jürgen T1 - Fatigue and fracture in dual-material specimens of nickel-based alloys fabricated by hybrid additive manufacturing N2 - The integration of additive manufacturing with traditional processes, termed hybrid additive manufacturing, has expanded its application domain, particularly in the repair of gas turbine blade tips. However, process-related defects in additively manufactured materials, interface formation, and material property mismatches in dual-material structures can significantly impact the fatigue performance of components. This investigation examines the low cycle fatigue and fatigue crack growth behaviors in dual-material specimens of nickel-based alloys, specifically the additively manufactured STAL15 and the cast alloy 247DS, at elevated temperatures. Low cycle fatigue experiments were conducted at temperatures of 950 °C and 1000 °C under a range of strain levels (0.3%–0.8%) and fatigue crack growth tests were conducted at 950 °C with stress ratios of 0.1 and −1. Fractographic and microscopic analyses were performed to comprehend fatigue crack initiation and crack growth mechanisms in the dual-material structure. The results consistently indicated crack initiation and fatigue fracture in the additively manufactured STAL15 material. Notably, fatigue crack growth retardation was observed near the interface when the crack extended from the additively manufactured STAL15 material to the perpendicularly positioned interface. This study highlights the importance of considering yield strength mismatch, as well as the potential effects of residual stresses and grain structure differences, in the interpretation of fatigue crack growth behavior at the interface. KW - Hybrid additive manufacturing KW - Dual-material nickel-based alloys KW - High-temperature fatigue crack growth KW - Low cycle fatigue PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-609340 DO - https://doi.org/10.1016/j.jmrt.2024.08.211 SN - 2238-7854 VL - 32 SP - 3737 EP - 3749 PB - Elsevier B.V. AN - OPUS4-60934 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Beygi Nasrabadi, Hossein A1 - Norouzi, Ebrahim A1 - Sack, Harald A1 - Skrotzki, Birgit T1 - Performance Evaluation of Upper‐Level Ontologies in Developing Materials Science Ontologies and Knowledge Graphs N2 - This study tackles a significant challenge in ontology development for materials science: selecting the most appropriate upper‐level ontologies for creating application‐level ontologies and knowledge graphs. Focusing on the use case of Brinell hardness testing, the research assesses the performance of various top‐level ontologies (TLOs)—basic formal ontology (BFO), elementary multiperspective material ontology (EMMO), and provenance ontology (PROVO)—in developing Brinell testing ontologies (BTOs). Consequently, three versions of BTOs are created using combinations of these TLOs along with their integrated mid‐ and domain‐level ontologies. The performance of these ontologies is evaluated based on ten parameters: semantic richness, domain coverage, extensibility, complexity, mapping efficiency, query efficiency, integration with other ontologies, adaptability to different data contexts, community acceptance, and documentation and maintainability. The results show that all candidate TLOs can effectively develop BTOs, each with its distinct advantages. BFO provides a well‐structured, understandable hierarchy, and excellent query efficiency, making it suitable for integration across various ontologies and applications. PROVO demonstrates balanced performance with strong integration capabilities. Meanwhile, EMMO offers high semantic richness and domain coverage, though its complex structure impacts query efficiency and integration with other ontologies. KW - Materials Science KW - Ontology KW - Knowledge Graph PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-612227 DO - https://doi.org/10.1002/adem.202401534 SN - 1527-2648 SP - 1 EP - 18 PB - Wiley AN - OPUS4-61222 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sonntag, Nadja A1 - Piesker, Benjamin A1 - Ávila Calderón, Luis A1 - Mohr, Gunther A1 - Rehmer, Birgit A1 - Agudo Jácome, Leonardo A1 - Hilgenberg, Kai A1 - Evans, Alexander A1 - Skrotzki, Birgit T1 - Tensile and Low‐Cycle Fatigue Behavior of Laser Powder Bed Fused Inconel 718 at Room and High Temperature N2 - This study investigates the room‐ and high‐temperature (650 °C) tensile and low‐cycle‐fatigue behavior of Inconel 718 produced by laser powder bed fusion (PBF‐LB/M) with a four‐step heat treatment and compares the results to the conventional wrought material. The microstructure after heat treatment is characterized on different length scales. Compared to the wrought variant, the elastic and yield properties are comparable at both test temperatures while tensile strength, ductility, and strain hardening capacity are lower. The fatigue life of the PBF‐LB/M variant at room temperature is slightly lower than that of the wrought material, while at 650 °C, it is vice versa. The cyclic stress response for both material variants is characterized by cyclic softening, which is more pronounced at the higher test temperature. High strain amplitudes (≥0.7%) at room temperature and especially a high testing temperature result in the formation of multiple secondary cracks at the transitions of regions comprising predominantly elongated grain morphology and columns of stacked grains with ripple patterns in the PBF‐LB/M material. This observation and pronounced crack branching and deflection indicate that the cracks are controlled by sharp micromechanical gradients and local crystallite clusters. KW - Additive manufacturing KW - Fatigue damage KW - Heat treatment KW - Inconel 718 KW - Laser powder bed fusion KW - Low-cycle fatigue KW - Tensile strength PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-599316 DO - https://doi.org/10.1002/adem.202302122 SN - 1527-2648 SP - 1 EP - 17 PB - Wiley AN - OPUS4-59931 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bhadeliya, Ashok A1 - Rehmer, Birgit A1 - Fedelich, Bernard A1 - Jokisch, T. A1 - Skrotzki, Birgit A1 - Olbricht, Jürgen T1 - Fatigue crack growth behavior of Alloy 247DS brazed joints at high temperatures N2 - Gas turbine components made of nickel-based alloys can be repaired through diffusion brazing. However, process-induced imperfections, defects within the brazing zone, and material property mismatches between the braze alloy and base material may facilitate crack initiation and propagation, ultimately leading to early component failure. To gain insight into the crack growth mechanism and quantitatively characterize fatigue crack growth behavior within brazing zones, fatigue crack growth (FCG) experiments were conducted on brazed joint specimens of nickel-based alloy Alloy 247DS at a temperature of 950 ◦C and a stress ratio R = 0.1. The FCG tests were complemented by fractographic and microstructural analyses, to elucidate the relationship between crack growth mechanisms and the microstructure of the brazed joint. The results demonstrate stable crack propagation within the brazing zone and the nickel-based braze alloy. The latter contains brittle eutectic boride phases and intermetallic phases that reduce the resistance to crack propagation compared to the parent material. This study demonstrates the applicability of standard FCG experimental procedures to fusion zones, thereby enabling a preliminary understanding of crack growth behavior in brazing zones. KW - Diffusion brazing KW - High-temperature fatigue crack growth KW - Nickel-based alloys KW - Alloy 247DS PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-615250 DO - https://doi.org/10.1016/j.msea.2024.147488 SN - 0921-5093 VL - 918 SP - 1 EP - 15 PB - Elsevier B.V. AN - OPUS4-61525 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Beygi Nasrabadi, Hossein A1 - Hanke, Thomas A1 - Skrotzki, Birgit T1 - Semantic Representation of Low‐Cycle‐Fatigue Testing Data Using a Fatigue Test Ontology and ckan.kupferdigital Data Management System N2 - Addressing a strategy for publishing open and digital research data, this article presents the approach for streamlining and automating the process of storage and conversion of research data to those of semantically queryable data on the web. As the use case for demonstrating and evaluating the digitalization process, the primary datasets from low‐cycle‐fatigue testing of several copper alloys are prepared. The fatigue test ontology (FTO) and ckan.kupferdigital data management system are developed as two main prerequisites of the data digitalization process. FTO has been modeled according to the content of the fatigue testing standard and by reusing the basic formal ontology, industrial ontology foundry core ontology, and material science and engineering ontology. The ckan.kupferdigital data management system is also constructed in such a way that enables the users to prepare the protocols for mapping the datasets into the knowledge graph and automatically convert all the primary datasets to those machine‐readable data which are represented by the web ontology language. The retrievability of the converted digital data is also evaluated by querying the example competency questions, confirming that ckan.kupferdigital enables publishing open data that can be highly reused in the semantic web. KW - Accessible KW - CKAN KW - Interoperable KW - Digitalizations KW - Ontologies KW - Reusable data KW - Fatigue testing PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-604991 UR - https://onlinelibrary.wiley.com/doi/10.1002/adem.202400675 DO - https://doi.org/10.1002/adem.202400675 SN - 1527-2648 SP - 1 EP - 11 PB - Wiley AN - OPUS4-60499 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -