5 Werkstofftechnik
Filtern
Dokumenttyp
- Zeitschriftenartikel (26)
- Forschungsdatensatz (12)
- Beitrag zu einem Tagungsband (10)
- Vortrag (6)
- Buchkapitel (1)
- Posterpräsentation (1)
Sprache
- Englisch (56) (entfernen)
Schlagworte
- Creep (11)
- Aging (9)
- Microstructure (7)
- Aluminium alloy (5)
- Shear modulus (5)
- Young's modulus (5)
- Additive manufacturing (4)
- EN AW-2618A (4)
- Elastic modulus (4)
- Mechanical testing (4)
- Ontology (4)
- P92 (4)
- Stress relaxation (4)
- AISI 316L (3)
- Additive Manufacturing (3)
- Aluminium (3)
- Aluminum alloys (3)
- Fatigue (3)
- Reference data (3)
- S-phase (3)
- Tempered martensite-ferritic steel (3)
- Ti-6Al-4V (3)
- AGIL (2)
- Alloy 2618A (2)
- Aluminum alloy (2)
- Brinell hardness (2)
- Coarsening (2)
- Copper alloys (2)
- Creep-fatigue (2)
- Damage (2)
- Data management (2)
- Data mapping (2)
- Dataset (2)
- Degradation (2)
- Electron microscopy (2)
- FAIR data (2)
- Microstructure evolution (2)
- Nickel-base alloy (2)
- Ostwald ripening (2)
- Phase-field simulation (2)
- Precipitation (2)
- Residual stress (2)
- S-Phase (2)
- TEM (2)
- Tempered Martensite Ferritic Steels (2)
- Tensile test (2)
- Transmission electron microscopy (2)
- 316L (1)
- 9-12%Cr steel (1)
- AM (1)
- Al-Cu alloy (1)
- Al-Cu-Li-alloy (1)
- Al2CuMg (1)
- Alloy 2818A (1)
- Anisotropy (1)
- Automated image analysis (1)
- Bitter technique (1)
- CALPHAD (1)
- Casting (1)
- Characterisation (1)
- Charpy test (1)
- Chemo-mechanical coupling (1)
- Computed Tomography (1)
- Creep behavior (1)
- Creep data (1)
- Creep, Creep Rupture, and Stress Rupture (1)
- Creep-Fatigue (1)
- Creep-fatigue interaction (1)
- Crystal Defects (1)
- Crystal plasticity (1)
- Cyclic loading (1)
- Cyclic softening (1)
- Data Interoperability (1)
- Data format (1)
- Data infrastructures (1)
- Data linking (1)
- Defects phase diagram (1)
- Defects thermodynamics (1)
- Deformation (1)
- Density-based model (1)
- Differential scanning calorimetry (DSC) (1)
- Digital image correlation (1)
- Digital material representation (1)
- Digital representation (1)
- Digital representations (1)
- Digital workflows (1)
- Digitization (1)
- Domain Ontology Development (1)
- Dwell periods (1)
- Dwell times (1)
- Dwell-Fatigue (1)
- EBSD (1)
- EN AW 2618A a (1)
- Elasticity (1)
- Environment (1)
- Expanding cavity model (1)
- FAIR (1)
- FAIR Data Management (1)
- FAIR research data management (1)
- Fatigue crack propagation (1)
- Fe-Al alloys (1)
- Ferritic-martensitic steels (1)
- Ferritic–martensitic steel (1)
- Fractography (1)
- General Chemistry (1)
- General Computer Science (1)
- General Engineering (1)
- General Materials Science (1)
- Hardness test (1)
- High cycle fatigue (1)
- High temperature mechanical properties (1)
- IN 718 (1)
- IN718 (1)
- In-situ Process Monitoring (1)
- Indentation (1)
- Industrial and Manufacturing Engineering (1)
- Interfacial anisotropy (1)
- Intermetallics (1)
- Iron aluminides (1)
- Knowledge Representation (1)
- Knowledge graph (1)
- Knowledge graphs (1)
- Laser Powder Bed Fusion (1)
- Laser Powder Bed Fusion (LPBF) (1)
- Laser beam melting (LBM) (1)
- Laser powder-based directed energy deposition (1)
- Lifetime prediction (1)
- Long-term aging (1)
- Long-term behavior (1)
- Low Cycle Fatigue (1)
- Low Cycle Fatigue (LCF) (1)
- Low cycle fatigue (1)
- Low strain (1)
- Low-cycle fatigue. (1)
- Magnetic domain distribution (1)
- Magnetic stray fields (1)
- Magnetomechanical effect (1)
- Material degradation (1)
- Materials Chemistry (1)
- Materials Testing (1)
- Materials informatics (1)
- Mechanical Engineering (1)
- Mechanical anisotropy (1)
- Mechanical behavior (1)
- Mechanics of Materials (1)
- Metadata schema (1)
- Metal magnetic memory (1)
- Metal seal (1)
- Metals and Alloys (1)
- Micromechanical model (1)
- Microstructure analysis (1)
- Microstructure-property-correlation (1)
- Misfitting precipitate (1)
- Modeling (1)
- Multiaxial deformation (1)
- Nimonic 75 (1)
- Non-destructive Materials (1)
- Notch (1)
- Number density (1)
- Ontologies (1)
- PBF-LB/M/316L (1)
- Parametric modeling (1)
- Plastic deformation (1)
- Precipitate shape (1)
- Precipitation hardening (1)
- Process development (1)
- Radii distribution (1)
- Reference material BCR-425 (1)
- Referenzdaten (1)
- Reheating (1)
- Relaxation fatigue (1)
- Relaxation tests (1)
- Reproducibility (1)
- S355 steel sheet (1)
- Safety (1)
- Selective laser melting (SLM) (1)
- Semantic Web Technologies (1)
- Simulation (1)
- Standardisation (1)
- Standardization (1)
- Strain difference (1)
- Strength (1)
- Structural steel (1)
- Symmetric dwell periods (1)
- Syngle Crystal alloy (1)
- T1 precipitate (1)
- Temperature dependence (1)
- Tensile Test Ontology (1)
- Tensile data (1)
- Tensile properties (1)
- Tensile testing (1)
- Thermo-Mechanical Fatigue (1)
- Thermomechanical Fatigue (TMF) (1)
- Thermomechanical fatigue (1)
- Thesaurus (1)
- Thickening (1)
- Topography (1)
- Transmission electron microscopy (TEM) (1)
- Vickers hardness (1)
- Visual ontology development (1)
- Vocabulary providers (1)
- Volume fraction (1)
- microstructural changes (1)
- γ″ phase (1)
- θ′ phase (1)
- θ′-(Al2Cu) precipitate phase (1)
Organisationseinheit der BAM
- 5 Werkstofftechnik (56)
- 5.2 Metallische Hochtemperaturwerkstoffe (56)
- 5.5 Materialmodellierung (10)
- 9 Komponentensicherheit (10)
- 5.1 Mikrostruktur Design und Degradation (9)
- 8 Zerstörungsfreie Prüfung (8)
- 9.6 Additive Fertigung metallischer Komponenten (6)
- 8.5 Röntgenbildgebung (5)
- 8.0 Abteilungsleitung und andere (3)
- 9.3 Schweißtechnische Fertigungsverfahren (3)
Eingeladener Vortrag
- nein (6)
Abstract While classically used to visualise the magnetic microstructure of functional materials (e.g., for magnetic applications), in this study, the Bitter technique was applied for the first time to visualise macroscopic deformation gradients in a polycrystalline low-carbon steel. Spherical indentation was chosen to produce a multiaxial elastic–plastic deformation state. After removing the residual imprint, the Bitter technique was applied, and macroscopic contrast differences were captured in optical microscopy. To verify this novel characterisation technique, characteristic “hemispherical” deformation zones evolving during indentation were identified using an analytical model from the field of contact mechanics. In addition, near-surface residual stresses were determined experimentally using synchrotron radiation diffraction. It is established that the magnetic domain distribution contrast provides deformation-related information: regions of different domain wall densities correspond to different “hemispherical” deformation zones (i.e., to hydrostatic core, plastic zone and elastic zone, respectively). Moreover, the transitions between these three zones correlate with characteristic features of the residual stress profiles (sign changes in the radial and local extrema in the hoop stress). These results indicate the potential of magnetic domain distribution imaging: visualising macroscopic deformation gradients in fine-grained ferromagnetic material with a significantly improved spatial resolution as compared to integral, mean value-based measurement methods.
To accelerate the growth of Industry 4.0 technologies, the digitalization of mechanical testing laboratories as one of the main data-driven units of materials processing industries is introduced in this paper. The digital lab infrastructure consists of highly detailed and standard-compliant materials testing knowledge graphs for a wide range of mechanical testing processes, as well as some tools that enable the efficient ontology development and conversion of heterogeneous materials’ mechanical testing data to the machine-readable data of uniform and standardized structures. As a basis for designing such a digital lab, the mechanical testing ontology (MTO) was developed based on the ISO 23718 and ISO/IEC 21838-2 standards for the semantic representation of the mechanical testing experiments, quantities, artifacts, and report data. The trial digitalization of materials mechanical testing lab was successfully performed by utilizing the developed tools and knowledge graph of processes for converting the various experimental test data of heterogeneous structures, languages, and formats to standardized Resource Description Framework (RDF) data formats. The concepts of data storage and data sharing in data spaces were also introduced and SPARQL queries were utilized to evaluate how the introduced approach can result in the data retrieval and response to the competency questions. The proposed digital materials mechanical testing lab approach allows the industries to access lots of trustworthy and traceable mechanical testing data of other academic and industrial organizations, and subsequently organize various data-driven research for their faster and cheaper product development leading to a higher performance of products in engineering and ecological aspects.
The age hardening response of a high-purity Al–4Cu–1Li–0.25Mn alloy (wt. %) during isothermal aging without and with an applied external load was investigated. Plate shaped nanometer size T1 (Al2CuLi) and θ′ (Al2Cu) hardening phases were formed. The precipitates were analyzed with respect to the development of their structure, size, number density, volume fraction and associated transformation strains by conducting transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM) studies in combination with geometrical Phase analysis (GPA). Special attention was paid to the thickening of T1 phase. Two elementary types of single-layer T1 precipitate, one with a Li-rich (Type 1) and another with an Al-rich (Defect Type 1) central layer, were identified. The results show that the Defect Type 1 structure can act as a precursor for the Type 1 structure. The thickening of T1 precipitates occurs by alternative stacking of These two elementary structures. The thickening mechanism was analyzed based on the magnitude of strain associated with the precipitation transformation normal to its habit plane. Long-term aging and aging under load resulted in thicker and structurally defected T1 precipitates. Several types of defected precipitates were characterized and discussed. For θ′ precipitates, a ledge mechanism of
thickening was observed. Compared to the normal aging, an external load applied to the peak aged state leads to small variations in the average sizes and volume fractions of the precipitates.
It is widely accepted that the magnetic state of a ferromagnetic material may be irreversibly altered by mechanical loading due to magnetoelastic effects. A novel standardized nondestructive testing (NDT) technique uses weak magnetic stray fields, which are assumed to arise from inhomogeneous deformation, for structural health monitoring (i.e., for detection and assessment of damage). However, the mechanical and microstructural complexity of damage has hitherto only been insufficiently considered. The aim of this study is to discuss the phenomenon of inhomogeneous “self-magnetization” of a polycrystalline ferromagnetic material under inhomogeneous deformation experimentally and with stronger material-mechanical focus. To this end, notched specimens were elastically and plastically deformed. Surface magnetic states were measured by a three-axis giant magnetoresistant (GMR) sensor and were compared with strain field (digital image correlation) and optical topography measurements. It is demonstrated that the stray fields do not solely form due to magnetoelastic effects. Instead, inhomogeneous plastic deformation causes topography, which is one of the main origins for the magnetic stray field formation. Additionally, if not considered, topography may falsify the magnetic signals due to variable lift-off values. The correlation of magnetic vector components with mechanical tensors, particularly for multiaxial stress/strain states and inhomogeneous elastic-plastic deformations remains an issue.
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.
Simulation of the θ′ Precipitation Process with Interfacial Anisotropy Effects in Al-Cu Alloys
(2021)
The effects of anisotropic interfacial properties and heterogeneous elasticity on the growth and ripening of plate-like θ′-phase (Al2Cu) in Al-1.69 at.% Cu alloy are studied. Multi-phase-field simulations are conducted and discussed in comparison with aging experiments. The precipitate/matrix interface is considered to be anisotropic in terms of its energy and mobility. We find that the additional incorporation of an anisotropic interfacial mobility in conjunction with the elastic anisotropy result in substantially larger aspect ratios of the precipitates closer to the experimental observations. The anisotropy of the interfacial energy shows comparably small effect on the precipitate’s aspect ratio but changes the interface’s shape at the rim. The effect of the chemo-mechanical coupling, i.e., the composition dependence of the elastic constants, is studied as well. We show that the inverse ripening phenomenon, recently evidenced for δ’ precipitates in Al-Li alloys (Park et al. Sci. Rep. 2019, 9, 3981), does not establish for the θ′ precipitates. This is because of the anisotropic stress fields built around the θ′ precipitates, stemming from the precipitate’s shape and the interaction among different variants of the θ′ precipitate, that disturb the chemo-mechanical effects. These results show that the chemo-mechanical effects on the precipitation ripening strongly depend on the degree of sphericity and elastic isotropy of the precipitate and matrix phases.
The effectiveness of the mechanism of precipitation strengthening in metallic alloys depends on the shapes of the precipitates. Two different material systems are considered: tetragonal γ′′ precipitates in Ni-based alloys and tetragonal θ′ precipitates in Al-Cu-alloys. The shape formation and evolution of the tetragonally misfitting precipitates was investigated by means of experiments and phase-field simulations. We employed the method of invariant moments for the consistent shape quantification of precipitates obtained from the simulation as well as those obtained from the experiment. Two well-defined shape-quantities are proposed: (i) a generalized measure for the particles aspect ratio and (ii) the normalized λ2, as a measure for shape deviations from an ideal ellipse of the given aspect ratio. Considering the size dependence of the aspect ratio of γ′′ precipitates, we find good agreement between the simulation results and the experiment. Further, the precipitates’ in-plane shape is defined as the central 2D cut through the 3D particle in a plane normal to the tetragonal c-axes of the precipitate. The experimentally observed in-plane shapes of γ′′-precipitates can be quantitatively reproduced by the phase-field model.
In recent years, the design and development of materials are strongly interconnected with the development of digital technologies. In this respect, efficient data management is the building block of material digitization and, in the field of materials science and engineering (MSE), effective solutions for data standardization and sharing of different digital resources are needed. Therefore, ontologies are applied that represent a map of MSE concepts and relationships between them. Among different ontology development approaches, graphical editing based on standard conceptual modeling languages is increasingly used due to its intuitiveness and simplicity. This approach is also adopted by the Materials-open-Laboratory project (Mat-o-Lab), which aims to develop domain ontologies and method graphs in accordance with testing standards in the field of MSE. To suit the actual demands of domain experts in the project, Ontopanel was created as a plugin for the popular open-source graphical editor diagrams.net to enable graphical ontology editing. It includes a set of pipeline tools to foster ontology development in diagrams.net, comprising imports and reusage of ontologies, converting diagrams to Web Ontology Language (OWL), verifying diagrams using OWL rules, and mapping data. It reduces learning costs by eliminating the need for domain experts to switch between various tools. Brinell hardness testing is chosen in this study as a use case to demonstrate the utilization of Ontopanel.