TY - CONF A1 - Schilling, Markus T1 - Vom Experiment zur semantischen Wissensrepräsentation: Datenstandards und Interoperabilität in der Materialcharakterisierung N2 - Im Zeitalter der digitalen Transformation rückt die strukturierte Erfassung und semantische Verknüpfung von Materialcharakterisierungsdaten immer stärker in den Fokus, um eine effiziente Nutzung über Disziplin- und Projektgrenzen hinweg zu gewährleisten. Dabei bilden etablierte Datenstandards und semantische Technologien sowie Ontologien die Grundlage für eine nach FAIR-Kriterien aufgebaute Dateninfrastruktur, die sowohl maschinenlesbare als auch nachvollziehbare Wissensrepräsentationen ermöglicht. In dieser Präsentation sollen Prinzipien interoperabler Datenarchitekturen erläutert werden, wobei auf die Bedeutung normkonformer Modelle und semantischer Konzeptualisierungen eingegangen wird. Dabei wird der steigende Bedarf an verlässlichen, reproduzierbaren und wiederverwendbaren Daten im Bereich der Materialwissenschaft und Werkstofftechnik adressiert, der insbesondere die Materialcharakterisierung und Werkstoffprüfung vor neue Herausforderungen stellt. Hinsichtlich der angestrebten Möglichkeiten zum erleichterten Datenaustausch kommen einheitlichen Datenformaten und -beschreibungen eine besondere Bedeutung zu. Anhand ausgewählter Publikationen und Demonstratoren wird aufgezeigt, wie Ontologien als verbindende Zwischenschicht unterschiedliche Material- und Verfahrensdomänen konsistent abbilden und zusammenführen können. Ein praktischer Anwendungsfall verdeutlicht die RDF-basierte Repräsentation von Zugversuchsdaten und deren Einbettung in ein Triple-Store-Datenbank-Umfeld. Hierbei fließen Erfahrungen aus der Entwicklung und Anwendung der PMD Core Ontology (PMDco) sowie normenkonformer Ontologien (z.B. Tensile Test Ontology, TTO) ein, welche im Rahmen des Projektes Plattform MaterialDigital (PMD, materialdigital.de) erstellt und betrachtet wurden. Darüber hinaus werden weitere methodische Ansätze und Entwicklungen aus diesem Projekt illustriert. T2 - Tagung Werkstoffprüfung 2025 CY - Dresden, Germany DA - 27.11.2025 KW - Wissensrepräsentation KW - Ontologie KW - Werkstoffprüfung KW - Digitale Transformation KW - Interoperabilität PY - 2025 AN - OPUS4-64944 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Marschall, Niklas T1 - Spinodal Decomposition in FeMnNiCoCu: Alloying effects N2 - Spinodal decomposition in multi-component alloys remains insufficiently understood, particularly when multiple driving forces govern phase evolution. Chemical thermodynamics provides reliable predictions of spinodal instabilities, but elastic energy contributions can significantly alter the boundaries of phase stability. In this work, we establish a framework to analyze phase stability in high-entropy alloys by combining Hessian-based spinodal analysis with convex hull constructions that capture miscibility gaps. This approach allows us to disentangle the roles of chemical, elastic, and kinetic factors in early-stage decomposition. Our results highlight how elastic contributions can extend the effective spinodal region beyond chemically predicted boundaries, thereby influencing microstructural pathways. This combined stability analysis offers new insights into the mechanisms governing decomposition and advancing the theoretical understanding of phase evolution in high-entropy alloys. T2 - FEMS EUROMAT 2025 CY - Granada, Spain DA - 14.09.2025 KW - High-entropy alloy KW - Elasticity KW - Phase stability KW - Hessian KW - Convex hull PY - 2025 AN - OPUS4-64263 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenberg, Rainer T1 - Modelling of hydrogen-induced ductility loss in titanium-based hydrogen storage N2 - One promising solution for decarbonisation is the use of hydrogen as energy carrier. Besides its exceptional advantages like high calorific value, better safety and non-existent harmful emissions, one major challenge is still hydrogen embrittlement of Ttitanium alloys used as a hydrogen storage. In this work, a method is presented that can numerically model and determine a threshold concentration of hydrogen in solid solution responsible for a sudden ductile-to-brittle transition. The origin of this sudden loss of ductility lies in the segregation kinetics thermodynamics that is modelled together with an elastoplastic fracture mechanics model. Starting from experimental fracture mechanics test data, a meaningful coupling mechanism was found for the fracture mechanics cohesive zone model in the form of a segregation-modified cohesive energy that triggers an acceleration of crack extension above defined concentration values. It can be demonstrated that above a threshold of only few atomic percent hydrogen in the solid solution, the segregated hydrogen concentration exceeds 20 at.%. The current results present a mechanism that enables the modelling of the sudden ductility loss triggered by a segregation-affected crack energy expression in titanium alloys exposed to hydrogen. This method is not only applicable to other various materials but can also be a substantial benefit for the safety assessment of hydrogen storage devices. T2 - 5th EMMC International Workshop 2025 CY - Vienna, Austria DA - 08.04.2025 KW - Segregation Transition KW - Hydrogen Embrittlement KW - Titanium Alloys KW - Crack Propagation KW - Ductile-to-Brittle Transition PY - 2025 AN - OPUS4-63177 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Murugan, Jegatheesan T1 - Extending Grain Boundary Phase Diagrams to Multi-Phase Boundary Diagrams N2 - Phase diagrams serve as fundamental blueprints for comprehending material behaviour and guiding material design. However, the phase diagrams are largely available only for the bulk phases. The thermodynamic properties and phase behaviour of defects, such as grain boundaries (GBs) and phase boundaries (PBs), are equally important for the safe design of materials. Recently, we developed CALPHAD-integrated density-based phase field model (DPF) to calculate the thermodynamic data of GBs. In the model, the GB was represented by a continuous relative atomic density field with reference to a single bulk density and a Gibbs free energy functional was derived. In this work, we extend the DPF model by re-deriving the Gibbs free energy functional for PBs lying between heterogeneous bulk phases of different atomic densities. Here, we use phase-specific atomic densities to normalize the phase properties on either side of the PB such that the relative density fields are continuous across the interface. Using the model, the multi-phase interfacial thermodynamic data are obtained and related phase boundary diagrams are constructed. We study binary and ternary Fe-Mn-X alloy systems. In the Fe-Mn multi-phase boundary diagram, a shrinkage in the α-ferrite region is observed. Integrated with CALPHAD databases, the developed model may be used to calculate the segregation of solute to the PBs, paving way to manipulate segregation behaviour for microstructure design. T2 - FEMS 2025 EUROMAT CY - Granada, Spain DA - 14.09.2025 KW - Phase boundary diagrams KW - Interface thermodynamics KW - CALPHAD PY - 2025 AN - OPUS4-64425 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fedelich, Bernard T1 - On the modeling of creep anisotropy of single Crystal Superalloys at low temperatures and high stresses N2 - Low-Temperature High Stress (LTHS) creep plays a crucial role in Ni-base Superalloys, particularly affecting components like blades near the root. Below 850°C, the precipitate microstructure remains stable, characterized by periodically arranged ’ cubic precipitates surrounded by the -matrix. In these conditions, macroscopic traces of cubic slip have been observed in <111> oriented tensile specimens, whereas their microscopic origin has been a topic of debate [1]. Later, it was shown by Discrete Dislocations simulations [2] that the apparent cubic slip is rather due to a lack of hardening in <111> specimens, which is related to the special dislocation structures that develop in this case. Furthermore, in LTHS conditions, Superlattice Intrinsic, Extrinsic Stacking Faults (SISF/SESF), or micro-twins are also frequently reported in crept specimens. Usually, these mechanisms are investigated separately, so that a unified picture and a detailed understanding of these mechanisms and their activation conditions have only recently emerged in the literature, despite the intensive investigations of the last decades [3-5]. The objective of this work is to develop a dislocation-based constitutive law that includes these recent developments. In particular, the pseudo-cubic slip mechanism is considered as resulting from the lack of hardening in <111> oriented tensile specimens and is represented by a novel estimate of the back-stresses based on the spectral decomposition of a tensorial representation of the back-stress. An additional novelty is that SISF- and SESF-related slip systems are accounted for as distinct slip systems with corresponding dislocation densities. The model has been implemented as a user-defined constitutive law for commercial Finite Element codes and identified as well as validated with data from the literature obtained with <001>, <011> and <111> oriented crystals [3,6]. It can be used in combination with a Representative Volume Element of the grain structure for simulation of creep in polycrystalline superalloys, including additively manufactured materials [7]. T2 - Materials Structure and Micromechanics of Fracture CY - Brno, Czech Republic DA - 23.06.2025 KW - Creep KW - Superalloy KW - Crystal plasticity KW - Single crystal KW - Model PY - 2025 AN - OPUS4-63551 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Leo, Reinhold A1 - Sobol, Oded A1 - Hango, Silas Ithete A1 - Saliwan Neumann, Romeo A1 - Askar, Enis A1 - Boellinghaus, Thomas T1 - Ex-situ investigation of the compatibility of Duplex Stainless Steel for high-pressure hydrogen applications N2 - The key to a successful transition into clean energy carriers such as hydrogen requires the construction of safe transportation pipelines made of alloys which are not susceptible to hydrogen assisted cracking. Duplex Stainless Steels (DSS) are considered as a proper class for components because of their many distinctive qualities. As this consideration depends strongly on the susceptibility level to Hydrogen Assisted Cracking (HAC), the DSS class has been broadly investigated under electrochemical charging conditions. In this work, the interplay between several factors controlling the level of HAC, was examined using light microscopy, high-pressure gaseous hydrogen pre-charging, Electron Backscatter Diffraction (EBSD), tensile testing, fractography and hydrogen concentration measurements using Carrier Gas Hot Extraction (CGHE). The effect of gaseous hydrogen on the mechanical properties with the role of hydrogen induced phase transformation have been investigated both in unused material and in high pressure pipeline section. In contrary to the common electrochemical charging described broadly in the literature, no significant martensitic phase transformation of the austenitic phase was observed. On the other hand, the influence of hydrogen on parameters such as elongation at fracture and reduction of area was noticeable. It is concluded based on the performance of DSS in gaseous hydrogen, that this material has a better potential for utilization in hydrogen applications. As for future experiments, the intention is to analyse the impact of high-pressure gaseous hydrogen on the welded components of this grade, and under mechanical load using the hollow specimen technique. T2 - 5th International Conference on Metals and Hydrogen CY - Ghent, Belgium DA - 14.10.2025 KW - High-Pressure Hydrogen KW - Pipelines KW - Duplex Stainless Steels KW - Hydrogen Assisted Cracking KW - Hollow Specimen Technique PY - 2025 SN - 978-9-08179-424-4 SP - 1 EP - 19 AN - OPUS4-64426 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - THES A1 - Kianinejad, Kaveh T1 - Multiscale Modelling of Creep Anisotropy in Additively Manufactured IN738LC N2 - Excellent creep resistance at elevated temperatures, i.e. T / Tm> 0.5, due to gamma-gamma’ microstructure is one of the main properties of nickel-based superalloys. Due to its great importance for industrial applications, much research has been devoted to understanding the underlying deformation mechanism in a broad spectrum of temperature and loading conditions. Additive Manufactured (AMed) nickel-based superalloys, while being governed by similar \gamma-gamma’ microstructure, exhibit AM-process specific microstructural characteristics, such as columnar grains, firm crystallographic texture (typically <001> fibre texture parallel to build direction) and compositional inhomogeneity, which in turn leads to anisotropic creep response in both stationary and tertiary phases. Despite the recent insights on the correlation between process parameters and the resulting microstructure, these materials' anisotropic creep behaviour and corresponding deformation mechanism are insufficiently understood. One reason is the lack of capable material models that link the microstructure to the mechanical behaviour. Within the present work, a multiscale approach has been developed to overcome this challenge by combining microstructure-based mesoscale and phenomenological macroscale models. The mesoscale model utilizes the Crystal Plasticity Finite Element Method (CPFEM) to include the microstructural characteristics and the relevant deformation mechanism on the polycrystalline scale. The mesoscale model was then used to perform virtual creep experiments required to calibrate the macroscale model. The developed approach has been applied to characterise the creep behaviour of AMed IN738LC. The effect of different slip systems, crystallographical texture, grain morphology, and Grain Boundary Sliding (GBS) on creep anisotropy at 850°C has been investigated. The approach's ability to capture the AM-specific characteristics and link them to the observed macroscale anisotropic response has been demonstrated, and the contribution of primary underlying deformation mechanisms to creep anisotropy has been elucidated. KW - Creep anisotropy KW - Crystal plasticity KW - Addtively manufactured Nickel-based Alloys alloy PY - 2025 SP - 1 EP - 135 PB - RWTH Aachen CY - Aachen AN - OPUS4-64598 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kianinejad, Kaveh A1 - Czediwoda, Fabian A1 - Glatzel, U. A1 - Völkl, R. A1 - Stöhr, B. A1 - Ávila Calderón, Luis A1 - Schriever, Sina A1 - Saliwan Neumann, Romeo A1 - Fedelich, Bernard A1 - Darvishi Kamachali, Reza T1 - Microstructure-based modelling of the anisotropic creep behaviour in additively manufactured INCONEL 718 N2 - The existing gap in the adequate prediction of the microstructure-property relationships remains a significant barrier to the safe application of the additively manufactured materials. This challenge is fundamentally tied to the intricate microstructural defects that emerge during the processing. Systematic microstructure-based modelling can offer solutions to address this bottleneck. In this work, we utilize a crystal plasticity model, developed for gamma''-strengthened Ni-base alloys and calibrated with single crystal tensile and creep tests of Inconel 718. By systematically refining the representative volume element complexity---from equiaxed to elongated grain morphologies, and from unimodal to bimodal orientation and grain size distributions---we demonstrate how each layer of structural realism contributes to the model’s predictive capacity. Creep tests of laser-based powder bed fusion (PBF-LB/M) manufactured samples in three orientations (with the tensile axis parallel, perpendicular, and 45° tilted relative to the building direction) were performed at 650° C, accompanied by electron backscatter secondary diffraction measurements. The results of our simulations reveal that the bimodal grain morphology and crystallographical texture significantly influence the observed creep anisotropy. We show that the elongated grain structure combined with grain boundary sliding plays a major role in the creep response, specifically in tilted specimens. KW - Additive manufactured Ni-base superalloys KW - Creep Anisotropy KW - Crystal plasticity PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-646884 DO - https://doi.org/10.1016/j.msea.2025.149029 VL - 945 SP - 1 EP - 15 PB - Elsevier B.V. AN - OPUS4-64688 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kostenko, Yevgen T1 - Harmonizing Viscoplastic Material Model Application within the BMBF-Project “DigitalModelling” of the Platform Material Digital- Basic Idea, General Strategy and Current Status N2 - For decades, Germany stands for excellent cutting-edge research in the field of so-called higher-value constitutive visco-plastic material models and can draw on a large and globally unique pool of material data. However, both the data and the model structure are extremely heterogeneous and sometimes fundamentally different from research center to research center and from industrial partner to industrial partner. To address the heterogeneity in the material model landscape appropriately, an adaptable material model for the specific application and the specific material is required. The relevant parameters for the adapted material model must be identified as objectively and automatically as possible. To achieve a potentially real-time capable implementation, the material model equation system should be abstracted. The “DigitalModeling” project, organized within the German Platform initiative Material Digital, aims to create a standard and an interface that harmonize the scientific and technical development of constitutive, visco-plastic material models, increase their visibility and maximize the productivity of future research funding. This presentation summarizes the basic idea, the strategy behind it as well as the current status of the project, which was started beginning of 2024. T2 - vgbe Workshop with Technical Exhibition Materials & Quality Assurance CY - Bergen, Norway DA - 07.05.2025 KW - Visco-plastic Material Model KW - Simulation Workflows KW - Ontologies KW - Digitalization PY - 2025 AN - OPUS4-64043 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schilling, Markus A1 - Marschall, Niklas A1 - Niebergall, Ute A1 - Wachtendorf, Volker A1 - Böhning, Martin T1 - Unveiling Effects of Biodiesel and Diesel on Environmental Stress Cracking of PE-HD N2 - The behavior of high‐density polyethylene with respect to resistance against environmental stress cracking (ESC) is usually regarded as an inherent material property being specific for respective types of PE‐HD and tested using standardized methods, conditions, and also standard testing liquids (usually aqueous surfactant solutions). On the other hand, for practical applications the ESC behavior of those polymeric materials, commonly used for pipes or containers, in contact with other liquids (e.g., fuels) is often of relevant interest, but for a reasonable assessment, where consistent benchmark data for a direct comparison are often missing, it is essential to determine the actually prevailing failure mode and classify it related to crack propagation or other mechanisms. Using the well‐established Full Notch Creep Test, which favorably allows for a detailed microscopic fracture surface analysis after failure, the behavior of two typical PE‐HD types for container applications is investigated in biodiesel and diesel and compared to a standard surfactant solution. This enables a clear identification of characteristic features of the interaction of biodiesel and diesel as sorptive fuels in contact with the polymer, revealing the complex interplay of sorption and plasticization as well as ESC inducing effects on PE‐HD, which could be clearly shown for both fuels. KW - Biodiesel KW - Confocal laser scanning microscopy (LSM) KW - Diesel KW - Full notch creep test (FNCT) KW - Plasticization PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-650525 DO - https://doi.org/10.1002/pen.70239 SN - 0032-3888 SP - 1 EP - 16 PB - Wiley CY - Hoboken (NJ) AN - OPUS4-65052 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -