5 Werkstofftechnik
Filtern
Dokumenttyp
- Vortrag (460)
- Zeitschriftenartikel (416)
- Posterpräsentation (116)
- Beitrag zu einem Tagungsband (76)
- Forschungsdatensatz (27)
- Buchkapitel (11)
- Dissertation (10)
- Forschungsbericht (7)
- Sonstiges (5)
- Sammelband (Herausgeberschaft für den kompletten Band) (3)
Sprache
- Englisch (965)
- Deutsch (160)
- Mehrsprachig (9)
- Französisch (2)
- Russisch (1)
Schlagworte
- Additive Manufacturing (67)
- Additive manufacturing (61)
- Corrosion (57)
- Microstructure (44)
- Glass (40)
- Ontology (39)
- Creep (35)
- Fatigue (30)
- Transmission electron microscopy (30)
- EBSD (28)
- Degradation (19)
- Sintering (19)
- CCS (18)
- Ceramics (18)
- Crack growth (18)
- Crystallization (17)
- Residual stress (17)
- LCF (16)
- Steel (16)
- 316L (15)
- Ontologie (15)
- Additive Fertigung (14)
- Ceramic (14)
- Oxidation (14)
- High entropy alloys (13)
- Ti-6Al-4V (13)
- High temperature corrosion (12)
- Machine Learning (12)
- Nanoparticles (12)
- Aging (11)
- Aluminium (11)
- CCUS (11)
- Carbon steel (11)
- Electron microscopy (11)
- Fraktographie (11)
- Mechanical properties (11)
- Particle size (11)
- Scanning electron microscopy (11)
- 3D printing (10)
- Alloy 2618A (10)
- CALPHAD (10)
- CO2 (10)
- Coarsening (10)
- Crystal plasticity (10)
- FAIR (10)
- Fractography (10)
- Glas (10)
- High entropy alloy (10)
- Low Cycle Fatigue (10)
- Neutron diffraction (10)
- SEM (10)
- Simulation (10)
- AISI 316L (9)
- DCB (9)
- Diffraction (9)
- Digitalization (9)
- EN AW-2618A (9)
- Glass fiber reinforced polymers (9)
- Impurities (9)
- Laser powder bed fusion (9)
- Mikrostruktur (9)
- Slurry (9)
- Thermoelectrics (9)
- VSSA (9)
- Water speciation (9)
- X-ray diffraction (9)
- AGIL (8)
- Alumina (8)
- Digitalisierung (8)
- Geothermal (8)
- High-temperature corrosion (8)
- Hydrogen (8)
- Kriechen (8)
- Martensitic steel (8)
- Nickel-base superalloys (8)
- S-phase (8)
- Semantic Web Technologies (8)
- Sulfidation (8)
- TEM (8)
- Aluminium alloy (7)
- Anisotropy (7)
- Damage (7)
- Heat treatment (7)
- Layerwise slurry deposition (7)
- Mechanical testing (7)
- Plattform MaterialDigital (7)
- Powder (7)
- Semantic Interoperability (7)
- Soda-lime silicate glass (7)
- Thermomechanical fatigue (7)
- Vickers (7)
- Water content (7)
- Zugversuch (7)
- Bioactive glass (6)
- CO2 quality (6)
- Composite (6)
- Computed Tomography (6)
- Data Interoperability (6)
- Environmental stress cracking (6)
- Foaming (6)
- Full Notch Creep Test (6)
- HIP (6)
- In situ (6)
- Knowledge Representation (6)
- LTCC (6)
- Laser Powder Bed Fusion (6)
- Lattice parameters (6)
- Metallic glasses (6)
- Nano powder (6)
- P92 (6)
- Plasticity (6)
- Polymer (6)
- Residual Stress (6)
- Robotic melting (6)
- Sandwich (6)
- Schadensanalyse (6)
- Schädigung (6)
- Selective laser melting (6)
- Superalloy (6)
- Supercritical/dense phase CO2 (6)
- TMF (6)
- Viscosity (6)
- Wind turbine blades (6)
- Alterung (5)
- Betriebsfestigkeit (5)
- CCU (5)
- Carbon capture (5)
- Carbon steels (5)
- Creep behavior (5)
- Dark-field transmission electron microscopy (DFTEM) (5)
- Data mapping (5)
- Diesel (5)
- Diffusion (5)
- Dislocation (5)
- Droplet corrosion (5)
- Electron backscatter diffraction (5)
- Environmental stress cracking (ESC) (5)
- FAIR data (5)
- FAIR data management (5)
- Fe-Al alloys (5)
- Fracture (5)
- High alloyed steel (5)
- High-density polyethylene (5)
- Inconel 686 (5)
- Intermetallics (5)
- Iron aluminides (5)
- Keramik (5)
- Knowledge graph and ontologies (5)
- Lebensdauer (5)
- Microgravity (5)
- Mikroplastik (5)
- Modeling (5)
- Nanoindentation (5)
- Non-destructive testing (5)
- Normung (5)
- PMD Core Ontology (5)
- Phase-field simulation (5)
- Pipeline (5)
- Pipeline network (5)
- Polymer matrix composites (5)
- Reference data (5)
- Sample preparation (5)
- Shear modulus (5)
- Stress relaxation (5)
- Superaustenite steel (5)
- Tensile Test (5)
- Tensile testing (5)
- Texture (5)
- ToF-SIMS (5)
- Transmission electron microscopy (TEM) (5)
- Vickers indentation (5)
- Wissensrepräsentation (5)
- Workflow (5)
- X-ray refraction (5)
- Young's modulus (5)
- 3D-printing (4)
- AISI 304L (4)
- Alkali ions (4)
- Alkali zinc borate glasses (4)
- Aluminum alloys (4)
- Bildanalyse (4)
- Binder Jetting (4)
- Brinell hardness (4)
- Calcination (4)
- Calcium cobaltite (4)
- Carbon capture storage (4)
- Carbon dioxide (4)
- Characterization (4)
- Chemically complex alloy (4)
- Coating (4)
- Composites (4)
- Compositionally complex alloys (4)
- Concrete (4)
- Crack propagation (4)
- Crack tip opening displacement (4)
- Creep-fatigue (4)
- Crystal orientation (4)
- Data Fusion (4)
- Data Space (4)
- Deuterium (4)
- EXAFS (4)
- Elastic modulus (4)
- Environmental Stress Cracking (4)
- Ermüdung (4)
- Fatigue crack growth (4)
- Finite element analysis (4)
- Fracture surface (4)
- Fracture toughness (4)
- Full-Notch Creep Test (FNCT) (4)
- GD-OES (4)
- Gassensorik (4)
- High Cycle Fatigue (4)
- High temperature (4)
- High-entropy alloy (4)
- High-entropy alloys (4)
- IN718 (4)
- In-space manufacturing (4)
- Inconel 718 (4)
- Internal friction (4)
- Kikuchi patterns (4)
- Low cycle fatigue (4)
- Martensite (4)
- Mechanical behavior (4)
- Metallic glass (4)
- Microplastics (4)
- Microstrucrue Design (4)
- Microstructural characterization (4)
- Microstructure Design (4)
- Microstructure evolution (4)
- Molecular dynamics (4)
- NTE (4)
- Nano (4)
- Nano-powder (4)
- Ni-Resist (4)
- Orientation (4)
- Oxidglas (4)
- PE-HD (4)
- Pattern matching (4)
- Pitting (4)
- Plastic deformation (4)
- Plattform Material Digital (4)
- Polyaniline (4)
- Precipitation (4)
- Raman spectroscopy (4)
- Recommendations (4)
- Reproducibility (4)
- Roughness (4)
- SIMS (4)
- Scale-bridging (4)
- Scarf repairs (4)
- Self-healing (4)
- Single crystal (4)
- Spectroscopy (4)
- Spray drying (4)
- Surface (4)
- Surface energy (4)
- TED-GC-MS (4)
- Tensile Test Ontology (4)
- Tensile test (4)
- Thermomechanics (4)
- Ultrasound (4)
- Virtual experiments (4)
- Welding (4)
- Whole-chain CCS scenario (4)
- XRD (4)
- Zerstörungsfreie Prüfung (4)
- Zirconia (4)
- 3D (3)
- 3D-Printing (3)
- Ab-initio (3)
- Advanced ceramics (3)
- Aluminium Alloy (3)
- Binder jetting (3)
- Bioceramics (3)
- Biodiesel (3)
- CFK (3)
- CLS (3)
- Carbon Fiber Reinforced Plastics (3)
- Carbon fibres (3)
- Cement (3)
- Ceramic spring (3)
- Computed tomography (3)
- Corrosion Fatigue (3)
- Corrosion fatigue (3)
- Coulomb explosion (3)
- Crack (3)
- Crack Propagation (3)
- Crack evolution (3)
- Crack healing (3)
- Creep data (3)
- Dark-field transmission electron microscopy (3)
- Datenbank (3)
- Defects (3)
- Destabilization (3)
- Dielectric breakdown (3)
- Dielectric strength (3)
- Diffraction Enhanced Imaging (3)
- Digital image correlation (3)
- Digitaler Zwilling (3)
- Digtial Representation (3)
- Diopside (3)
- Elastic constants (3)
- Electron Backscatter Diffraction (3)
- Electronic Lab Notebook (3)
- FIB (3)
- Ferritic-martensitic steels (3)
- Fracture Toughness (3)
- Fracture mechanics (3)
- Fracture surface analysis (3)
- Full notch creep test (FNCT) (3)
- GFRP (3)
- General Materials Science (3)
- Glass ceramic (3)
- Glass powder (3)
- Glass transition (3)
- Glass-ceramic (3)
- Glass-ceramics (3)
- Gold nanoparticles (3)
- Grain boundaries (3)
- Grain boundary (3)
- Grain boundary engineering (3)
- H2Safety@BAM (3)
- Hardness (3)
- High Entropy Alloy (3)
- High temperature mechanical properties (3)
- IN 718 (3)
- ISRU (3)
- In situ tensile test (3)
- Infrarotspektroskopie (3)
- Interfacial strength (3)
- Interoperability (3)
- Inverted classroom (3)
- Iron (3)
- Iron oxide nanoparticles (3)
- Kikuchi diffraction (3)
- Kikuchi pattern (3)
- Knowledge graph (3)
- Korrosion (3)
- Laser (3)
- Laser ablation in liquid (3)
- Laser beam melting (3)
- Laser cladding (3)
- Laser scanning microscopy (LSM) (3)
- Lattice misfit (3)
- Layerwise Slurry Deposition (3)
- Lightweight materials (3)
- Lithium Ion Batteries (3)
- Luftultraschall (3)
- ML (3)
- Mechanical Engineering (3)
- Mechanics of Materials (3)
- Mechanische Eigenschaften (3)
- Metadata schema (3)
- Microhardness (3)
- Microstructure analysis (3)
- Multilayer (3)
- NMR spectroscopy (3)
- Nanomaterials (3)
- Nickel-based superalloys (3)
- Ontologies (3)
- Oxide Glasses (3)
- PBF-LB/M/316L (3)
- PMD (3)
- PMDco (3)
- Permeability (3)
- Phase transformations (3)
- Phase-field (3)
- Polyethylene (3)
- Porosity (3)
- Pressure-assisted sintering (3)
- Pulveraktivkohle (3)
- REM (3)
- Referenzdaten (3)
- Relaxation (3)
- Research Data Management (3)
- Residual Stresses (3)
- Residual stresses (3)
- Rotor blade (3)
- Röntgenrefraktion (3)
- S-Phase (3)
- SLM (3)
- Scintillators (3)
- Selective Laser Melting (3)
- Semantic Data (3)
- Semantic Web (3)
- Shape-memory alloys (3)
- SiO2 (3)
- Silicate Glasses (3)
- Silicon Carbide (3)
- Single-crystals (3)
- Slow crack growth (SCG) (3)
- Sol-gel (3)
- Sol-gel coating (3)
- Solid-state (3)
- Solubility (3)
- Stress intensity factor (3)
- Sulfiding (3)
- Superalloys (3)
- Superlegierung (3)
- Surface crystallization (3)
- Syngle Crystal alloy (3)
- TDEP (3)
- Temperature (3)
- Tempered Martensite Ferritic Steels (3)
- Tempered martensite-ferritic steel (3)
- Tensile data (3)
- Thermal expansion (3)
- Thermo-Mechanical Fatigue (3)
- Thermogravimetrie (3)
- Titanium (3)
- Titanium oxide (3)
- Topography (3)
- UV-irradiation (3)
- Utilization (3)
- Vickers hardness (3)
- Viscoplasticity (3)
- Wasser (3)
- Wind energy (3)
- Wind turbine blade shells (3)
- Windenergie (3)
- µ-gravity (3)
- μ-gravity (3)
- 3D Druck (2)
- AM (2)
- Additiv gefertigter Stahl (2)
- Adiabatic calorimeter (2)
- Ageing (2)
- Agglomerates (2)
- Aggressive environment (2)
- Air-coupled ultrasonic testing (2)
- Airborne ultrasonic testing (2)
- Al-Cu-Li alloys (2)
- Al2O3 (2)
- Alloy design (2)
- Aluminosilicate glasses (2)
- Aluminum (2)
- Aluminum alloy (2)
- Analysis (2)
- Analytische Zentrifuge (2)
- Annealing (2)
- Aquifer (2)
- Atom probe tomography (2)
- Austenitic stainless steel (2)
- Austenitic steel 316L (2)
- Automation (2)
- Bacteria (2)
- Belebtschlamm (2)
- Biaxial strength (2)
- Bio Ceramics (2)
- Bioactive Glass (2)
- Bioactivity (2)
- Biofilm (2)
- Bond energy (2)
- Bone regeneration (2)
- Brittle fracture (2)
- Bruchflächen (2)
- Bulk metallic glasses (2)
- CO2-storage (2)
- CT (2)
- Calciumcobaltit (2)
- Calciummanganat (2)
- Capture (2)
- Carbon (2)
- Carbon capture and storage (2)
- Carbon storage (2)
- Casting (2)
- CeO2 (2)
- Ceramic multilayer (2)
- Ceria (2)
- Chemo-mechanical coupling (2)
- Chromium oxide (2)
- Coatings (2)
- Condensate (2)
- Condensation (2)
- Continnum damage model (2)
- Copper (2)
- Copper alloys (2)
- Corrosion resistance (2)
- CrCoNi (2)
- CrMnFeCoNi (2)
- Crack propagation analysis (2)
- Creep-Fatigue (2)
- Crevice corrosion (2)
- Crop protection products (2)
- Cross linking (2)
- Cure process (2)
- Cyclic softening (2)
- DLS (2)
- Data Management (2)
- Data Structures (2)
- Data analysis (2)
- Data management (2)
- Dataset (2)
- Debinding (2)
- Deep Learning (2)
- Dehnungsfehler (2)
- Density (2)
- Density-based Phase-Field Modelling (2)
- Density-based Thermodynamics (2)
- Density-based model (2)
- Densty-based Thermodynamics (2)
- Dental (2)
- Depth-profiling (2)
- Dielectric properties (2)
- Diffraction Elastic Constants (2)
- Diffraction contrast (2)
- Diffusion coefficient (2)
- Digital material representation (2)
- Digital representation (2)
- Digitization (2)
- Diopsid (2)
- Dislocations (2)
- Dispersion process (2)
- Distribution function (2)
- Ductile iron (2)
- Dynamic mechanical analysis (DMA) (2)
- EDX (2)
- EDXRD (2)
- Early oxidation (2)
- Elastic microstructure (2)
- Elasticity (2)
- Electron beam induced modification (2)
- Electron beam-induced fragmentation (2)
- Electron diffraction (2)
- Electron energy (2)
- Electron-beam-induced modification (2)
- Energy distribution (2)
- Environmental Stress Cracking (ESC) (2)
- Environmentally assisted cracking (2)
- Epoxy (2)
- Erneuerbare Energien (2)
- Extensometer (2)
- FAIR Data Management (2)
- Fahrrad (2)
- Faser-Kunststoff-Verbunde (2)
- Faserkunststoffverbunde (2)
- Faseroptische Sensorik (2)
- Fatigue damage (2)
- Fatigue of sandwich shell structures (2)
- Fatigue performance (2)
- Fatigue testing (2)
- FeCr- alloys (2)
- Ferroelectret (2)
- Ferroelektret (2)
- Fiber reinforced polymer (2)
- Flowability (2)
- Fluoride phosphate glasses (2)
- Fracture Surface Analysis (2)
- Fracture surface energy (2)
- Fraktografie (2)
- Fungi (2)
- GFK (2)
- Geführte Ultraschallwellen (2)
- Gender gap (2)
- Gitterkonstanten (2)
- Glass Digital (2)
- Glass composition (2)
- Glass forming (2)
- Gold (2)
- Granules (2)
- HEA (2)
- Hard machining (2)
- Heat Treatment (2)
- High Alloyed Steel (2)
- High Entropy Alloys (2)
- High Temperature Corrosion (2)
- High Temperature Testing (2)
- Hochentropie-Legierung (2)
- Hochtemperatur (2)
- Hot pressing (2)
- Hot stage microscopy (2)
- Hydrogen permeation (2)
- IR (2)
- Imaging techniques (2)
- In-situ (2)
- Inconel 625 (2)
- Infrared spectroscopy (2)
- Infrastructure (2)
- Injection (2)
- Interface (2)
- Interfacial shear strength (2)
- Interphase (2)
- Ionic porosity (2)
- Joined nickel-based alloys (2)
- Kavitation (2)
- Keramikfeder (2)
- Kikuchi (2)
- Kleinprobenprüfung (2)
- Knowledge Graph (2)
- Kontrastierung (2)
- L-PBF (2)
- LPBF (2)
- LSD-print (2)
- Laminography (2)
- Laser Powder Bed fusion (2)
- Lattice distortion (2)
- Layerwise (2)
- Lead borate glasses (2)
- Leckdetektion (2)
- Li-ion battery (2)
- Long-term behavior (2)
- Long-term storage (2)
- Lorenz transmission electron microscopy (2)
- Lunar habitat (2)
- Lunar regolith (2)
- Lunar regolith simulant (2)
- MEA (2)
- MOUSE (2)
- Manganese oxide (2)
- Manufacturing (2)
- Mars (2)
- Martensitic transformation (2)
- Mass transport (2)
- Material Digital (2)
- Material degradation (2)
- Material digital (2)
- Materials Modelling (2)
- Materials science (2)
- Medium Entropy Alloys (2)
- Melt pool boundary (2)
- Metal seal (2)
- Metrologie zur Wasserstoffspeicherung (2)
- Micro-shrinkages (2)
- Micromechanical model (2)
- Microstructural analysis (2)
- Microstructural evolution (2)
- Microstructure and texture (2)
- Microstructure-property-correlation (2)
- Mikrostrukturentwicklung (2)
- Mixed Ca-K-Na phosphates (2)
- Mixed gas atmosphere (2)
- Mobility (2)
- Monte-Carlo Simulation (2)
- Multiaxial deformation (2)
- Multifunctional nanoparticles (2)
- Multilayer technology (2)
- Multilayertechnik (2)
- NDT (2)
- NFDI (2)
- Na and K rhenanites (2)
- Nano particle (2)
- Nano screening (2)
- Nanomaterial (2)
- Nanopulver (2)
- Nanostructure quantification (2)
- Native oxide (2)
- Neutron Diffraction (2)
- Nickel alloys (2)
- Nickel-base alloy (2)
- Niobium alloying (2)
- Notches (2)
- Nucleation (2)
- OECD TG 124 (2)
- Ontologien (2)
- Ontology development (2)
- Orientation precision (2)
- Oriented surface crystallization (2)
- Ostwald ripening (2)
- Oxidation behavior (2)
- Oxyfuel (2)
- Parametric modeling (2)
- Particle morphology (2)
- Partikelgrößenverteilung (2)
- Paving (2)
- Phase change material (2)
- Phase diagram (2)
- Phase separation (2)
- Phase transformation (2)
- Phase-Field Simulations (2)
- Phasenidentifikation (2)
- Photon counting detector (2)
- Pipelines (2)
- Polyethylen (2)
- Polyethylen hoher Dichte (2)
- Polyethylene, PE-HD (2)
- Polymer Matrix Composites (2)
- Porcelain (2)
- Pores (2)
- Preceramic polymer (2)
- Pressure assisted sintering (2)
- Probengrößeneffekt (2)
- Process monitoring (2)
- Protective coating (2)
- Präparation (2)
- Push-out Test (2)
- Quasicrystal (2)
- Rapid solidification (2)
- Ratio refinement (2)
- Reaction sintering (2)
- Reaction-sintering (2)
- Recycling (2)
- Reference material (2)
- Refractory high entropy alloys (2)
- Ressidual stress (2)
- Review (2)
- Rissentwicklung (2)
- Risswachstum (2)
- Roboter (2)
- Robotische Glasschmelzanlage (2)
- Robotische Schmelzanlage (2)
- Rotorblattschalen (2)
- Round robin (2)
- Röntgen-Refraktion (2)
- Röntgenbeugung (2)
- S355 steel sheet (2)
- SAXS (2)
- Safety assessment (2)
- Salt eutectics (2)
- Scanning transmission electron microscopy (STEM) (2)
- Schadensprävention (2)
- Schwingstreifen (2)
- Semantic Representation (2)
- Semantic web (2)
- Semantisches Web (2)
- SensRef (2)
- Sensorik (2)
- Shear bands (2)
- Short-range order (2)
- Sibayak (2)
- Silicon carbide (2)
- Silicon nanowires (2)
- Silver diffusion (2)
- Silver metallization paste (2)
- Silver nanoparticle (2)
- Silver-glass-metallization-paste (2)
- Simulation of concrete (2)
- Single-Crystal (2)
- Sinter additive (2)
- Sintering additives (2)
- Sintern (2)
- Size distribution (2)
- Slow crack growth (2)
- Small-angle scattering (2)
- Soda-lime-silica glass (2)
- Solar sintering (2)
- Sorption (2)
- Space (2)
- Spannungs-Dehnungs-Verhalten (2)
- Spannungsriss (2)
- Spring constant (2)
- Stainless steel (2)
- Standard (2)
- Standardisierung (2)
- Standardization (2)
- Starch (2)
- Starch nanoparticle (2)
- Steels (2)
- Storage (2)
- Strength (2)
- Stress corrosion cracking (2)
- Structural Health Monitoring (SHM) (2)
- Structural steel (2)
- Struktur (2)
- Sulphidation (2)
- Superalloy single crystals (2)
- Superconducting magnet (2)
- Supercritical CO2 (2)
- Surface Energy (2)
- Surface nucleation (2)
- Surface treatments (2)
- Symmetric dwell periods (2)
- Synchrotron Tomography (2)
- Synchrotronstrahlung (2)
- Synthetic air (2)
- Temperaturschwankungen (2)
- Tensile Properties (2)
- Tensile properties (2)
- Thermal Spray (2)
- Thermal energy storage (2)
- Thermoanalyse (2)
- Thermodynamics (2)
- Thermoelectric (2)
- Thermoelectric oxide (2)
- Thermoelectric oxides (2)
- Thermoelectric properties (2)
- Thermographie (2)
- Thermography (2)
- Thermogravimetry (2)
- Thermomechanik (2)
- Thermoplastic (2)
- Thermoset polymers (2)
- Ti64 (2)
- TiAl5V4 (2)
- Titan (2)
- Topografie (2)
- Topographie (2)
- Toughness (2)
- Transmission electron microscope (TEM) (2)
- Transmissionselektronenmikroskopie (2)
- Transparent ceramics (2)
- Tribologie (2)
- Two Photon Polymerization (2)
- Under cyclic loading (2)
- Upconversion (2)
- Utilization, and storage (CCUS) technology (2)
- Viscous sintering (2)
- Volume specific surface area (2)
- Wall thickness (2)
- Wandler (2)
- Water-based (2)
- Weibull Distribution (2)
- Weibull distribution (2)
- Werkstoffprüfung (2)
- Wetting (2)
- Wind turbine (2)
- Wood protection (2)
- X-Ray Diffraction (2)
- X-ray absorption spectroscopy (2)
- X-ray computed tomography (CT) (2)
- X-ray laminography (2)
- XANES (2)
- Zero-g (2)
- Zugeigenschaften (2)
- corrosion (2)
- robotische Glasschmelzanlage (2)
- Öffentliche Sicherheit (2)
- 12%Cr steel (1)
- 150 Years (1)
- 2PP (1)
- 316L stainless steel (1)
- 3D REM (1)
- 3D Reconstruction (1)
- 3D etching (1)
- 3D glass structure model (1)
- 3D imaging (1)
- 3D materialography (1)
- 3D metallography (1)
- 3D-Metallographie (1)
- 3D-finite element modeling (1)
- 4-Dimensional scanning transmission (1)
- 5G (1)
- 9-12% Cr ferritic-martensitic steels (1)
- 9-12%Cr steel (1)
- 9–12%Cr steel (1)
- AFM (1)
- AFM based test methods (1)
- ATZ (1)
- Abgasturbolader Heißteile (1)
- Abrasion (1)
- Abwasser (1)
- Accelerated integration scheme (1)
- Accelerated temporal integration (1)
- Accessible (1)
- Acid-leaching (1)
- Acids (1)
- Active thermography (1)
- Additive manufactured Ni-base superalloys (1)
- Adiabatic shear bands (1)
- Adolf Martens (1)
- Advanced high strength steels (1)
- Advanced manufacturing (1)
- Advanced wastewater treatment (1)
- Aerospace (1)
- Age hardening (1)
- Aggressive environement (1)
- Aggressive environments (1)
- Aggressive gases (1)
- Aging mechanisms (1)
- Al alloys (1)
- Al-Cu alloy (1)
- Al-Cu binary alloy system (1)
- Al-Cu-Li-alloy (1)
- Al-Li alloys (1)
- Al2CuMg (1)
- Alcium alkali phosphate (1)
- Alkali aluminosilicate glasses (1)
- Alkali and alkaline earth silicate and borate glass (1)
- Alkali zinc borate glass (1)
- Alkali-activated materials (1)
- Allgemeine Grundlagen (1)
- Alloy (1)
- Alloy 2818A (1)
- Alloy Safety (1)
- Alloy microstructure (1)
- Alloys (1)
- Alloys' Safety (1)
- Alpha-tricalcium phosphate (1)
- Alumina coatings (1)
- Alumina toughened zirconia (1)
- Aluminium alloys (1)
- Aluminiumlegierung (1)
- Aluminum Alloy Aging (1)
- Amorphization (1)
- Amorphous silica (1)
- Analyse (1)
- Analytical scanning electron microscopy (1)
- Analytical services (1)
- Analytik (1)
- Angle measurement (1)
- Anhydrite (1)
- Anticorrosion (1)
- Anwendungen (1)
- Approximant (1)
- Aquifer fluid (1)
- Artefact (1)
- Artificial weathering (1)
- Atacama Desert (1)
- Atmospheric Plasma Spraying (1)
- Atmospheric plasma spraying (1)
- Atomic packing factor (1)
- Atomistic Simulation (1)
- Atomistic simulations (1)
- Atomization (1)
- Aufbau von Festkörpern (1)
- Aussonderugnsrate (1)
- Austenite-to-martensite phase transformation (1)
- Austenitic alloys (1)
- Austenitic cast iron (1)
- Austenitic steel (1)
- Austenitischer Stahl (1)
- Automatable digital approach (1)
- Automated Bragg angle determination (1)
- Automated analysis (1)
- Automated finite element analysis (1)
- Automated image analysis (1)
- Automatische Finite Element Simulation (1)
- BCS (1)
- BET (1)
- BTEX (1)
- BTS (1)
- Bacterial attachment (1)
- Batch reactions (1)
- Beanspruchung (1)
- Behmite (1)
- Berstdruck (1)
- Bilanzierung (1)
- Bimodal distribution (1)
- Binders/binding (1)
- Bio Ceramic (1)
- Bio active ceramic (1)
- Bio-ceramic engineering (1)
- Bioactive (1)
- Bioactive bone grafting material (1)
- Bioactive glass scaffold (1)
- Bioceramic (1)
- Biogeochemical cycling (1)
- Biogeochemistry (1)
- Biomineralisation (1)
- Biopolymer (1)
- Bioresorbable (1)
- Biphasic calcium phosphate (1)
- Bitter technique (1)
- Blended learning (1)
- Blähen (1)
- Boden (1)
- Bone marrow-derived mesenchymal stem cell (1)
- Borate (1)
- Borate glasses (1)
- Borosilicate glass (1)
- Bragg angles (1)
- Brass (1)
- Bravais lattice (1)
- Bravais lattices (1)
- Breakdown strength (1)
- Brittle / ductile fracture behavior (1)
- Brown-rot fungi (1)
- Brownian motion (1)
- Bruch (1)
- Bruchflächenanalyse (1)
- Bruchflächenauswertung (1)
- Bubble formation (1)
- Bundesoberbehörden (1)
- Burst (1)
- Burst test (1)
- C. lap-shear (1)
- CALPHAD database analysis (1)
- CALPHAD databases analysis (1)
- CCUS, supercritical/dense phase CO2, carbon steels, martensitic steel, superaustenite steel, droplet corrosion (1)
- CFRP (1)
- CKAN (1)
- CMSX4 (1)
- CO2 Corrosion (1)
- CO2 corrosion (1)
- CO2 pipeline transport (1)
- CO2 separation membranes (1)
- CO2-Speicherung (1)
- CO2-corrosion (1)
- Cabon capture and storage (1)
- Calcium Cobaltite (1)
- Calcium alkali orthophosphate materials (1)
- Calcium manganate (1)
- Calcium sulfates (1)
- Calculated intrinsic fracture toughness (1)
- Calibration (1)
- Cantor alloy (1)
- Carbide phase NbC (1)
- Carbidic austempered ductile iron (1)
- Carbon steels (1)
- Carbon Capture (1)
- Carbon Capture, Utilization and Storage (CCUS) (1)
- Carbon Fibers (1)
- Carbon Fibre (1)
- Carbon capture, utilization and storage technology (1)
- Carbon fibre-reinforced-plastics (1)
- Carbon nanotubes (1)
- Casing (1)
- Catalogue of services (1)
- Cavitation (1)
- Ccs (1)
- CdTe quantum dots (1)
- Cellular substructure (1)
- Cellulose (1)
- Cement-based materials (1)
- Centrifugal casting (1)
- Centrifugal compressor wheel (1)
- Ceramic multilayers (1)
- Ceramic nano particles (1)
- Ceramic springs (1)
- Ceramics 3D printing (1)
- Cerium oxide (1)
- Certification Standard 22 (1)
- Certified Referencematerial (1)
- Cetrifugal Liquid Sedimentation CLS (1)
- Chalcogenides (1)
- Characterisation (1)
- Charpy test (1)
- Chemically Complex Alloy (1)
- Chemically complex alloys (1)
- Chemische Analyse (1)
- Chemometrics (1)
- Chemometrie (1)
- Chromatography (1)
- Chromia (1)
- Chrystal orientation (1)
- Classification (1)
- Clay ISRU (1)
- Co-axial monitoring (1)
- Co-firing (1)
- Co-segregation (1)
- Co-firings (1)
- Co2-Storage (1)
- Cobald based alloy (1)
- Coefficient of thermal expansion (1)
- Complex borides (1)
- Complex concentrated alloy (CCA) (1)
- Complex loading (1)
- Component assessment (1)
- Composite materials (1)
- Composite pressure vessels (1)
- Composite recycling (1)
- Composite structures (1)
- Composite testing (1)
- Compositionally complex alloy (1)
- Concrete 3D-printing (1)
- Condensed Matter Physics (1)
- Confined catalyst (1)
- Coniophora puteana (1)
- Contact angle (1)
- Contact fatigue (1)
- Contact mechanics (1)
- Contamination (1)
- Cooling rate (1)
- Cooling simulations (1)
- Coordinate measurement machine (1)
- Copper vacancies (1)
- Corrosion and storage (CCUS) technology (1)
- Corrosion costs (1)
- Corrosion mechanism (1)
- Corrosion pits (1)
- Corrosion protection (1)
- Covid-19 (1)
- Cow stress (1)
- Coûts de la corrosion (1)
- Cr2O3 (1)
- CrN/NbN (1)
- Crack arrest (1)
- Crack growth in air (1)
- Crack initiation (1)
- Crack opening displacement (1)
- Cracks (1)
- Craze-crack mechanism (1)
- Craze–crack mechanism (1)
- Creation-relaxation algorithm (1)
- Creep anisotropy (1)
- Creep behaviour (1)
- Creep mechanisms (1)
- Creep strength (1)
- Creep under thermal cycling (1)
- Creep, Creep Rupture, and Stress Rupture (1)
- Creep-fatigue interaction (1)
- Critical energy release rate (1)
- Crop protection formulations (1)
- Cross-sectioning (1)
- Crosslinking (1)
- Cryogenic (1)
- Cryogenic cycling (1)
- Crystal Defects (1)
- Crystal Orientation (1)
- Crystal Plasticity Modelling (1)
- Crystal Texture (1)
- Crystal growth (1)
- Crystal growth velocity (1)
- Crystal lattice (1)
- Crystal lattice period (1)
- Crystal morphology (1)
- Crystalline defects (1)
- Crystallographic texture (1)
- Cubical Iron Oxide (1)
- Cubical shape (1)
- Cupriavidus metallidurans (1)
- Cuttlefish (1)
- Cycle jump (1)
- Cyclic R-Curve (1)
- Cyclic loading (1)
- Cyclic oxidation (1)
- Cyclic steam oxidation (1)
- Cytocompatibility (1)
- D. aging (1)
- D. creep D. viscoelasticity (1)
- DCB geometry (1)
- DED-L (1)
- DIN (1)
- Damage Behavior (1)
- Damage Tolerance (1)
- Damage behavior (1)
- Damage evolution (1)
- Damage mechanisms (1)
- Data Exchange (1)
- Data Integration (1)
- Data Mapping (1)
- Data format (1)
- Data fusion (1)
- Data infrastructures (1)
- Data linking (1)
- Data pipeline (1)
- Data pipeline concept (1)
- Data processing (1)
- Data space (1)
- Data storage (1)
- Data structure (1)
- Datenfusion (1)
- Datenmanagement (1)
- Datenökosystem (1)
- Debonding (1)
- Deep learning (1)
- Defect detection (1)
- Defect population (1)
- Defects engineering (1)
- Defects phase diagram (1)
- Defects thermodynamics (1)
- Deformation (1)
- Deformation behavior (1)
- Deformation mechanisms (1)
- Degradation signatures (1)
- Demonstrators (1)
- Dense phase (1)
- Density-based Model (1)
- Density-based phase-field modelling (1)
- Dental ceramics (1)
- Dentine (1)
- Deposition microstructure (1)
- Design of experiment (1)
- Desorption (1)
- Die casting (1)
- Dielectric Spectroscopy (1)
- Dielectric breakdown strength (1)
- Dielectric characterization (1)
- Diesel Fuel (1)
- Differential scanning calorimetry (1)
- Differential scanning calorimetry (DSC) (1)
- Diffusivity (1)
- Digital Transformation (1)
- Digital Twin (1)
- Digital representations (1)
- Digital workflow (1)
- Digital workflows (1)
- Digitalizations (1)
- Dimensional mismatch of crystalline lattice periods (misfit) (1)
- Directional grain growth (1)
- Discrete element method (1)
- Dislocation avalanches (1)
- Dislocation substructure (1)
- Disordered assemblies (1)
- Disorientation (1)
- Dissimilar metal weld (1)
- Dissolved water (1)
- Distributed fiber optic sensing (1)
- Distributed fiber optic sensors (1)
- Distributed fibre optic sensors (1)
- Diversity (1)
- Domain Ontology Development (1)
- Double notched creep specimen (1)
- Driving physical mechanism (1)
- Droplet (1)
- Druckgasspeicher (1)
- Dry preparation (1)
- Drywood termite (1)
- Dual-energy (1)
- Durchschlagfestigkeit (1)
- Dwell periods (1)
- Dwell times (1)
- Dwell-Fatigue (1)
- Dynamic mechanical analysis (1)
- Dynamic recrystallization (1)
- Dynamisch Mechanische Analyse (1)
- EAC-1A (1)
- EASA (1)
- EC4SafeNano (1)
- EFTEM (1)
- EIS (1)
- EN AW 2618A (1)
- EN AW 2618A a (1)
- EPR (1)
- Early stages (1)
- Early sulfidation (1)
- Efficiency (1)
- Eigenschaften (1)
- Eigenspannung (1)
- Elastic energy (1)
- Elastic properties (1)
- Elctronic Lab Notebook (1)
- Electric conductivity (1)
- Electric field distribution (1)
- Electric field strength (1)
- Electrical insulation (1)
- Electrical insulators (1)
- Electrical resistance (1)
- Electrochemical characterisation (1)
- Electrochemical deposition (1)
- Electrochemical dressing (1)
- Electrochemical impedance spectroscopy (1)
- Electromicroscopy (1)
- Electron Microscopy (1)
- Electron back-scattered diffraction (1)
- Electron backscattered diffraction (1)
- Electron backscattered diffraction (EBSD) (1)
- Electron beam-induced charging (1)
- Electron microscopy, transmission (1)
- Electronic (1)
- Electropolishing (1)
- Elektronisches Laborbuch (ELN) (1)
- Elektrotechnische Grundlagen (1)
- Enamel (1)
- End of life (1)
- Endothelial progenitor cell (1)
- Endurance Limit (1)
- Energiedisersive Röntgenspektroskopie (1)
- Energiespeicherung (1)
- Energiewende (1)
- Energy harvesting (1)
- Energy transition (1)
- Entwicklung (1)
- Environment (1)
- Epitaxial films (1)
- Epoxidharz (1)
- Epoxy Resin (1)
- Epoxy resin (1)
- Equilibrium relaxation (1)
- Ermüdungsriss (1)
- Etching (1)
- European Centre (1)
- Eutectic (1)
- Expanding cavity model (1)
- Experimental and numerical techniques (1)
- Explosionsschutz (1)
- Explosive welding (1)
- Exposed metal sites (1)
- FAIR Data (1)
- FAIR data. (1)
- FAIR principles (1)
- FAIR research data management (1)
- FCH JU (1)
- FIB Tomography (1)
- FNCT (1)
- FSDC (1)
- FT-IR (1)
- Fabrication (1)
- Fabrication method (1)
- Faceting (1)
- Facilitated activation (1)
- Failure mechanisms (1)
- Failure rate (1)
- Failure test (1)
- Faser (1)
- Faser-Kunststoff-Verbund (1)
- Faseroptik (1)
- Faserverstärkte Kunstoffe (1)
- Fatigue Crack Growth (1)
- Fatigue Life Evaluation (1)
- Fatigue Testing (1)
- Fatigue crack propagation (1)
- Fatigue crack propagation stages (1)
- Fatigue fracture (1)
- Fatigue of sandwich structures (1)
- Fatigue striations (1)
- Fe-Mn steels (1)
- Federkonstante (1)
- Feldspar (1)
- Fem (1)
- Female noble prize winners (1)
- Femtosecond laser (1)
- Ferritic Alloys (1)
- Ferritic steels (1)
- Ferritic–martensitic steel (1)
- Ferrous phosphate hydrate (1)
- Fertigungsprozess (1)
- Fertigungstechnologie (1)
- Festigkeit (1)
- Fiber (1)
- Fiber reinforced polymers (1)
- Fiber-matrix interface (1)
- Fiber/matrix bond (1)
- Fibre reinforced plastic (1)
- Fibre/matrix bond (1)
- Fibre/matrix bonding (1)
- Film depositition (1)
- Filters (1)
- Fine Powder (1)
- Finite element method (1)
- Finite elmenet simulation (1)
- Finite-Elemente-Methode (1)
- Finland (1)
- Firing (1)
- First derivative (1)
- First year students (1)
- Flipped classroom (1)
- Flow Coefficient (1)
- Fluorescence spectroscopy (1)
- Fluoride nanoparticles (1)
- Fluorolytic sol−gel (1)
- Focused Ion Beam (1)
- Focussed ion beam growth (1)
- Foliengießen (1)
- Force-distance diagram (1)
- Formerkennung (1)
- Four-point bending test (1)
- Fourier series (1)
- Fourier transform infrared spectroscopy (1)
- Fracture Mechanics (1)
- Fracture behavior (1)
- Fracture surfaces (1)
- Fragility (1)
- Freeze Drying (1)
- Freeze casting (1)
- Fresnoit (1)
- Fresnoite (1)
- Friction (1)
- Friction Stir Welding (1)
- Friction stir processing (1)
- Frozen state photopolymerization (1)
- Fuel sorption (1)
- Full Notch Creep Test (FNCT) (1)
- Full notch creep test (1)
- Full-Notch Creep Test (1)
- Full-notch creep test (1)
- Fullerite (1)
- Functional fatigue (1)
- Fused Filament Fabrication (1)
- GC-MS (1)
- GMR (1)
- GMR sensors (1)
- Gas flow assisted powder deposition (1)
- Gas permeation (1)
- Gas storage (1)
- Gasabgabe (1)
- Gasdetektion (1)
- Gasgehalt (1)
- Gasturbinen (1)
- Gd3+ (1)
- Gefüge (1)
- Gefüge (Werkstoffkunde) (1)
- Gefügeanalyse (1)
- Gefügerekonstruktion (1)
- Gefügeuntersuchung (1)
- Gefügte Nickelbasislegierungen (1)
- General Aviation (1)
- General Chemistry (1)
- General Computer Science (1)
- General Engineering (1)
- Geometrical factors (1)
- Geopolymers (1)
- Gitterfehlpassung (1)
- Glas fibre reinforced polymer (1)
- GlasDigital (1)
- Glasfaserverstärkter Kunststoff (1)
- Glasmatrixkomposit (1)
- Glass Ceramic (1)
- Glass Fibres (1)
- Glass capillaries (1)
- Glass crystallization stress (1)
- Glass fiber reinforced polymer (1)
- Glass fiber-epoxy composites (1)
- Glass fibre (1)
- Glass fibre reinforced plastics (1)
- Glass forming melts (1)
- Glass liner (1)
- Glass manufacturing (1)
- Glass matrix composite (1)
- Glass melt (1)
- Glass melting (1)
- Glass scintillator (1)
- Glass screening device (1)
- Glass structure (1)
- Glass transformation temperature (1)
- Glass-ceramics definition (1)
- Glasses (1)
- Glasspeicher (1)
- Gleichgewicht (1)
- Global stability criterion (1)
- Gnomonic projections (1)
- Gold nanoparticle synthesis (1)
- Grade S960QL steel (1)
- Gradient-enhanced damage (1)
- Gradient-enhanced fatigue model (1)
- Grain Boundary (1)
- Grain Boundary Corrosion (1)
- Grain Boundary Phase Diagram (1)
- Grain Boundary Segregation (1)
- Grain Boundary Spinodal (1)
- Grain boundary oxidation (1)
- Grain boundary phase diagram (1)
- Grain boundary precipitates (1)
- Grain boundary structure (1)
- Grain boundary thermodynamics (1)
- Grain growth (1)
- Grain structure (1)
- Granulometrie (1)
- Graphic design (1)
- Graphite (1)
- Grenzflächenenergie (1)
- Growth kinetics (1)
- Growth rate (1)
- Grundlagen des Maschinenbaus (1)
- Grünfolieneigenschaften (1)
- Gypsum (1)
- HCF (1)
- HDPE Soprption (1)
- HDPE Sorption (1)
- HV-Insulation (1)
- Hardness test (1)
- Hartbearbeitung (1)
- Hausner ratio (1)
- Heat Treatments (1)
- Heat accumulation (1)
- Heat-resistant nickel alloys (1)
- Heißgasextraktion (1)
- Heißgaskorrosion (1)
- Hertzian cracks (1)
- Hierarchical microstructure (1)
- Hierarchical microstructure Premartensite (1)
- Hierarchical porosities (1)
- High - temperature (1)
- High - temperature corrosion (1)
- High Voltage Insulation (1)
- High alloyed steels (1)
- High cycle fatigue (1)
- High density polyethylene (1)
- High energy radiation (1)
- High entropy superalloys (1)
- High interstitial austenitic steel (1)
- High pressure (1)
- High pressure gas storage (1)
- High temperature nickel-based eutectic alloys (1)
- High temperature oxidation (1)
- High temperatures (1)
- High-Entropy Alloys (1)
- High-Entropy Materials (1)
- High-Temperature Corrosion (1)
- High-density polyethylene (PE-HD) (1)
- High-strength steel (1)
- High-temperature oxidation (1)
- High-temperature properties (1)
- High-voltage testing (1)
- High‐temperature corrosion (1)
- Hipims (1)
- Hochentropielegierung (1)
- Hochentropielegierungen (1)
- Hochleistungskeramik (1)
- Hochspannungsprüfung (1)
- Hochtemperaturbrennstoffzelle (1)
- Hochtemperaturermüdung (1)
- Homogenization (1)
- Honing (1)
- Honing Stone (1)
- Horizon 2020 (1)
- Host-guest hybrid materials (1)
- Hot Press (1)
- Hot isostatic pressing (1)
- Hot isostatic pressing (HIP) (1)
- Hybrid Manufacturing (1)
- Hydrogel (1)
- Hydrogen diffusivity (1)
- Hydrogen gas (1)
- Hydrogen permeability (1)
- Hydrogen sensor (1)
- Hydrogen sensors (1)
- Hydrogen storage (1)
- Hydrogen storage tank (1)
- Hydrothermal Ageging (1)
- Hydrous glass (1)
- Hygrothermal (1)
- Hyper-arid (1)
- IASCC (1)
- IN738LC (1)
- IR spectroscopy (1)
- Imaging (1)
- Impact damage (1)
- Impact wear (1)
- Implant failures (1)
- Implants (1)
- In situ diffraction (1)
- In situ synthesis (1)
- In situ thermal-annealing experiment (1)
- In-Situ Testing (1)
- In-situ ED-XRD (1)
- In-situ Process Monitoring (1)
- In-situ SEM micro shear deformation (1)
- In-situ composites (1)
- In-situ diffraction (1)
- In-situ process monitoring (1)
- In-situ tomography (1)
- In-vivo (1)
- In718 (1)
- Incipient plasticity (1)
- Inclusion cluster (1)
- Inclusion size (1)
- Inconel 686 coating (1)
- Incremental lifetime models (1)
- Indentation (1)
- Indentation fracture toughness (1)
- Indentation hardness (1)
- Industrial and Manufacturing Engineering (1)
- Informationstechnische Grundlagen (1)
- Infrared nano AFM (1)
- Initial attachment (1)
- Inkjet (1)
- Inter layer time (1)
- Interdiffusion (1)
- Interface Strength (1)
- Interfacial Spinodal (1)
- Interfacial Strength (1)
- Interfacial anisotropy (1)
- Interfacial free energy (1)
- Interlaboratory comparability (1)
- Intermediate scale (1)
- Intermetallic (1)
- Intermetallische FeAl-Legierungen (1)
- Intermittent microplasticity (1)
- Intermodulation AFM (1)
- Internal Sulfidation (1)
- Internal Surfaces (1)
- Internal oxidation (1)
- Internal stresses (1)
- Interoperable (1)
- Intrinsic stress (1)
- Invar (1)
- Inverse ostwald ripening (1)
- Investment casting (1)
- Ion beam erosion Sectioning (1)
- Iron meteorite (1)
- Iron oxide (1)
- Irradiation (1)
- Irregular topography (1)
- Isostatic hot pressing (HIP) (1)
- JMAK model (1)
- Joints/joining (1)
- KCl (1)
- KI (1)
- Kalzinierung (1)
- Kennwertermittlung (1)
- Keramische Folien (1)
- Kernel average misorientation (1)
- Keywords: Poly(ether ether ketone) (1)
- Kikuchi bands (1)
- Klebung (1)
- Knowledge Graphs (1)
- Knowledge graphs (1)
- Knowledge representation (1)
- Komponentenprüfung (1)
- Kreislaufwirtschaft (1)
- Kriechermüdung (1)
- Kriechversuche (1)
- Kristallisation (1)
- Kristallorientierung (1)
- Kristallsystem (1)
- Kunststoffe (1)
- Kupfer (1)
- Kurzfaser-verstärkte Thermoplaste (1)
- Kurzzeitfestigkeit (1)
- L-PBF 316L (1)
- LIBS (1)
- LMD (1)
- LSD print (1)
- LTCC multilayer (1)
- Laboratory X-ray diffraction (1)
- Laminographie (1)
- Langzeitstabilität (1)
- Laser Beam Melting (1)
- Laser Cladding (1)
- Laser Poeder Bed Fusion (1)
- Laser Powder Bed Fusion (LPBF) (1)
- Laser Scanning Microscopy (1)
- Laser Scanning Microscopy (LSM) (1)
- Laser beam melting (LBM) (1)
- Laser curing (1)
- Laser induced slipcasting (1)
- Laser light scattering (1)
- Laser powder-based directed energy deposition (1)
- Laser-Pulverbettschmelzen (1)
- Laser-induced slip casting (1)
- Laserbearbeitung (1)
- Laserscanningmikroskopie (LSM) (1)
- Lattice distortions (1)
- Lattice parameter determination (1)
- Lattice point density (1)
- Lattice rotation (1)
- Lattice structures (1)
- Lattices (1)
- Laves phase (1)
- Layer depostion (1)
- Layer system (1)
- Layered manganese oxide (1)
- Layering misalignment (1)
- Lebensdauervorhersage (1)
- Lecture films (1)
- Lecture videos (1)
- Legierung mit komplexer Zusammensetzung (1)
- Lehrfilm (1)
- Lehrfilmformate (1)
- Life cycle (1)
- Lifetime prediction (1)
- Light curing (1)
- Lightweighting (1)
- Limestone Filler (1)
- Lindemann criterion (1)
- Linear elastic fracture mechanics (1)
- Linked open data (1)
- Liquid Metal Embrittlement (1)
- Liquid metal embrittlement (1)
- Liquid phase sintering (1)
- Liquid-metal embrittlement (1)
- Lithium-ion batteries (1)
- Lithography-based technologies (1)
- Local landscape evolution (1)
- Localized plasmons (1)
- Log-normal distribution (1)
- Long-term aging (1)
- Long-term calculation (1)
- Low Cycle Fatigue (LCF) (1)
- Low carbon steel (1)
- Low expansion (1)
- Low strain (1)
- Low-Cycle Fatigue (LCF) (1)
- Low-Cycle-Fatigue (1)
- Low-cycle fatigue (1)
- Low-cycle fatigue. (1)
- Low-cycle-fatigue behaviour (1)
- Low-loading (1)
- Lösungsmittel (1)
- Lötverbindung (1)
- MGS-1 regolith simulant (1)
- MOF-74 (1)
- Machine learning (1)
- Magmatic and hydrothermal processes (1)
- Magnetic domain distribution (1)
- Magnetic domains (1)
- Magnetic shape memory (1)
- Magnetic stray field (1)
- Magnetic stray fields (1)
- Magnetische Domänen (1)
- Magnetoelastic effect (1)
- Magnetoelastischer Effekt (1)
- Magnetomechanical effect (1)
- Martensitic steel (1)
- Martensitic steels (1)
- Martensitic structure (1)
- Master curve (1)
- Masterschädigungslinie (1)
- Mat-o-lab (1)
- Material Life Cycle (1)
- Material characterization (1)
- Material defects (1)
- Material failure (1)
- Material modeling (1)
- Material oxidation (1)
- MaterialDigital (1)
- Materialcharakterisierung (1)
- Materialentwicklung (1)
- Materialkreislauf (1)
- Materialmodell (1)
- Materialprüfung (1)
- Materials Chemistry (1)
- Materials Data Space (1)
- Materials Science (1)
- Materials Testing (1)
- Materials and Processes Data Reusability (1)
- Materials informatics (1)
- Materials science and engineering (1)
- Materials testing (1)
- Materialwissenschaft (1)
- Mathematisch-naturwissenschaftliche Grundlagen (1)
- Matrix (1)
- Matrix residual stress (1)
- Mean atomic number (1)
- Mean-field modelling (1)
- Mechanical Behavior (1)
- Mechanical Properties (1)
- Mechanical and thermal testing (1)
- Mechanical anisotropy (1)
- Mechanical deformation (1)
- Mechanisches Verhalten (1)
- Mechanistic Modelling (1)
- Medium entopy alloy (1)
- Medium entropy alloy (1)
- Medium entropy alloys (1)
- Medium-entropy alloy (1)
- Mehrachsige Verformung (1)
- Mehrskalenmodell (1)
- Melting (1)
- Meta material (1)
- Metal Magnetic Memory (1)
- Metal additive manufacturing (1)
- Metal and alloys (1)
- Metal magnetic memory (1)
- Metal powder characterization (1)
- Metall (1)
- Metallic Glass (1)
- Metallic components (1)
- Metallic materials (1)
- Metallic silver precipitates (1)
- Metallography (1)
- Metals and Alloys (1)
- Metformin (1)
- Methodology (1)
- Metrologie (1)
- Metrology (1)
- Micro computed tomography (1)
- Microbiologically influenced corrosion (1)
- Micromanipulation (1)
- Microplastic stress (1)
- Microsegregation (1)
- Microspine (1)
- Microstructur (1)
- Microstructural changes of a Fe Si alloy (1)
- Microstructural orientation (1)
- Microstructure Analysis (1)
- Microstructure Characterization (1)
- Microstructure Evolution (1)
- Microstructure characterisation (1)
- Microstructure design (1)
- Microstructure modification (1)
- Microstructure, γ/γ' misfit (1)
- Microstrucure reconstruction (1)
- Microwave technology (1)
- Mid-Level Ontology for MSE (1)
- Mikro-Computertomographie (1)
- Mikrogravitation (1)
- Mikrostrukturuntersuchung (1)
- Milling (1)
- Mindedestberstdruck (1)
- Mini-UAV (1)
- Miniature specimens (1)
- Mis-match (1)
- Misfitting precipitate (1)
- Misorientation (1)
- Missing acknowledgment (1)
- Mixed conductors (1)
- Mixed-linkers (1)
- Mn-oxides (1)
- Mn3O4 (1)
- Model (1)
- Model alloy (1)
- Modell (1)
- Moisture (1)
- Molecular Dynamics (1)
- Molten salt (1)
- Monte-Carlo-Analysis (1)
- Moon (1)
- Mortar (1)
- Mortel (1)
- Multi-principal element alloys (1)
- Multiaxial stress state (1)
- Multilayer ceramic technology (1)
- Multilayers (1)
- Multiple cracks (1)
- NFDI-MatWerk (1)
- NGS (1)
- NIST (1)
- NMR (1)
- Nahinfrarotspektroskopie (1)
- Nano CRM (1)
- Nano material (1)
- Nano metal fluorides (1)
- Nano-assemblies (1)
- Nano-ceramic-additive-manufacturing photoresin (1)
- Nano-composite (1)
- Nano-landscape (1)
- Nano-powder characterization (1)
- Nano-safety (1)
- Nano-scratch test (1)
- NanoCAM (1)
- Nanocomposites (1)
- Nanocrystalline alloys (1)
- Nanocrystalline structure (1)
- Nanoelectromechanical systems (NEMS) (1)
- Nanomaterial screening (1)
- Nanoparticle structure (1)
- Nanoparticle synthesis (1)
- Nanopartikel (1)
- Nanoplattform (1)
- Nanopowder (1)
- Nanoribbons (1)
- Nanoscale multilayers (1)
- Nanostructure (1)
- Natural (1)
- Natural silver wires (1)
- Nb3Sn (1)
- Near Infrared Spectroscopy (1)
- Negative charged microparticle (1)
- Net zero (1)
- Networking (1)
- New standards (1)
- Ni-Mn-Ga (1)
- NiMaGa (1)
- NiTi (1)
- Nickel based coatings (1)
- Nickel-base superalloy (1)
- Nimonic 75 (1)
- Nitride (1)
- Noble metal nanoparticles (1)
- Non-Destructive Testing (1)
- Non-desired foaming (1)
- Non-destructive Materials (1)
- Non-metallic inclusions (1)
- Non-serrated inhomogeneous flow (1)
- Nondestructive testing (1)
- Notch (1)
- Nucleation mode (1)
- Nucleation tendency (1)
- Number density (1)
- Numerische Simulation (1)
- Nydrogen melting (1)
- OECD TG (1)
- Oberflächenaktive wässrige Medien (1)
- Oberflächenkeimbildung (1)
- Online (1)
- Online Process Monitoring (1)
- Online quality control (1)
- Online teaching (1)
- Ooxidation (1)
- Optic (1)
- Optical and Magnetic Materials (1)
- Optical backscatter reflectometry (1)
- Optical centrifugation (1)
- Optical criterion (1)
- Optical criterion of brittleness (1)
- Optical fibre (1)
- Optical properties (1)
- Optical properties of glasses and ceramics (1)
- Optical spectroscopy (1)
- Optical tweezers (1)
- Ordered/disordered structures (1)
- Ordering (1)
- Orientation refinement (1)
- Orientation relationship (1)
- Orientation-dependent microstructure (1)
- Orowan Mechanism (1)
- Osteogenesis (1)
- Overaging (1)
- Oxidation protection (1)
- Oxide (1)
- Oxide coatings (1)
- Oxide glass (1)
- Oxide scale (1)
- Oxides (1)
- Oxygen evolution reaction (1)
- P92 steels (1)
- PA6.6 (1)
- PE-HD Sorption (1)
- PLS-DA (1)
- PPA (1)
- PV modules (1)
- Packaging (1)
- Parabolic flight (1)
- Particle Size Distribution (1)
- Particle size determination (1)
- Particle-bed binder jetting (1)
- Partikelgröße (1)
- Passive components and circuits (1)
- Patent (1)
- Peem (1)
- Permittivity reduction (1)
- Persistent luminescence (1)
- Persistent luminescent (1)
- Phase Diagram (1)
- Phase Diagrams (1)
- Phase Separation (1)
- Phase analysis (1)
- Phase field crystal (1)
- Phase field method (1)
- Phase field model (1)
- Phase field simulation (1)
- Phase stability (1)
- Phase-Field Simulation (1)
- Phase-field Simulation (1)
- Phase-field model (1)
- Phase-field modelling (1)
- Phosphate (1)
- Phosphors (1)
- Photocatalysis (1)
- Photocleavable organosilanes (1)
- Photodynamic therapy (1)
- Photopolymer composites (1)
- Phototrophs (1)
- Photovoltaic modules (1)
- Physical aging (1)
- Physical properties (1)
- Physically based material model (1)
- Physics-informed Neural Network (1)
- Phytolith (1)
- Pitting corrosion (1)
- Planetary surface (1)
- Plasma imaging (1)
- Plasma nanocoatings (1)
- Plasma spray (1)
- Plasmon enhancement (1)
- Platform Material Digital (1)
- Platform Material Digital (PMD) (1)
- Platform MaterialDigital (1)
- Platform MaterialDigital (PMD) (1)
- Platinum-group-metals (1)
- Plattform Material Digital (PMD) (1)
- Pole figures (1)
- Polymer Matrix Composite (1)
- Polymer analysis/characterization (1)
- Polymer composite (1)
- Polymer-Ceramic-Composite (1)
- Polymer-ceramic mixtures (1)
- Polymer-matrix composites (PMC) (1)
- Polymeric Materials (1)
- Polymerwissenschaften (1)
- Polymer–matrix composites (1)
- Polyolefins (1)
- Polypropylene (1)
- Polystyrene (1)
- Polyurethane (1)
- Pore (1)
- Porosification (1)
- Porous materials (1)
- Portfolio (1)
- Positron annihilation spectroscopy (1)
- Powder bed additive manufacturing (1)
- Powder bed density (1)
- Powder deposition (1)
- Powder diffraction (1)
- Powder flow (1)
- Powder processing (1)
- Powder rheology (1)
- Powder-based processes (1)
- Powdered activated carbon (1)
- Power factor (1)
- Power law (1)
- Power plant (1)
- Power-to-Gas (1)
- Precipitate shape (1)
- Precipitates (1)
- Precipitation Analysis (1)
- Precipitation hardening (1)
- Preparation (1)
- Preventive strategies (1)
- Principal stress (1)
- Principal stress components (1)
- Printing (1)
- ProMoAM (1)
- Process (1)
- Process Monitoring (1)
- Process development (1)
- Processing window (1)
- Production scatter (1)
- Proficiency test (1)
- Projection center (1)
- Projekt AGIL - Alterung additiv gefertigter metallischer Materialien und Komponenten (1)
- Properties (1)
- Property simulation (1)
- Protection (1)
- Prozessmonitoring (1)
- Pseudosymmetry (1)
- Pull-out (1)
- Pull-out composite materials (1)
- Pultruded fiber rods (1)
- Pycnometry (1)
- Quality assurance (1)
- Quantitative Precipitation Analysis (1)
- Quantitative image analysis (1)
- Quantum dots (1)
- Radiation-matter interaction (1)
- Radii distribution (1)
- Radon transform (1)
- Rafting (1)
- Raman (1)
- Reaction Sintering (1)
- Real time growth control (1)
- Real-time deformation (1)
- Real-time qPCR (1)
- Reference Data (1)
- Reference Dataset (1)
- Reference Material (1)
- Reference material BCR-425 (1)
- Reference nanomaterials (1)
- Reference nanoparticles (1)
- Referenzmaterial (1)
- Referenzorganismus (1)
- Referenzverfahren (1)
- Refractory alloy (1)
- Refractory chemically complex alloy (1)
- Refractory chemically complex alloys (1)
- Refractory superalloys (1)
- Regelwerke (1)
- Regolith (1)
- Reheating (1)
- Rejuvenation (1)
- Relaxation fatigue (1)
- Relaxation metallic glasses (1)
- Relaxation tests (1)
- Relaxationsphänomene (1)
- Reliability (1)
- Reliable characterization (1)
- Renewable ernergy (1)
- Repair of sandwich shell structures (1)
- Repair patch (1)
- Residual strains (1)
- Residual stress analysis (1)
- Resistance (1)
- Resistance spot welding (1)
- Resistance stress (1)
- Resonance testing (1)
- Restberstfestigkeit (1)
- Reusability (1)
- Reusable data (1)
- Rheology (1)
- Rhodonia placenta (1)
- Risikoanalyse (1)
- Rissausbreitung (1)
- Risse (1)
- Rissform (1)
- Rissfortschritt (1)
- Rissheilung (1)
- Rissverlauf (1)
- Robot-assisted galss melting (1)
- Robotic glass melting (1)
- Rohrprobekörper (1)
- Rotorblatt (1)
- Rotorblätter (1)
- Round Robin (1)
- SDC (1)
- SEM micrography (1)
- SEM wood characterization (1)
- SEN-Probe (1)
- SHM (1)
- SO2 (1)
- STEM (1)
- Safety (1)
- Sailplane Development Panel (1)
- Sall-angle scattering (1)
- Salt melt (1)
- Salzschmelzen (1)
- Samarium doped ceria (1)
- Sample holder (1)
- Sand blasting (1)
- Sandwich structures (1)
- Sandwichstruktur (1)
- Scaffold (1)
- Scaffold geometry (1)
- Scaffolds (1)
- Scale-dependent behavior (1)
- Scan strategies (1)
- Scanning Electron Microscopy (SEM) (1)
- Scanning acoustic microscopy (SAM) (1)
- Scanning electron microscope (1)
- Scanning electron microscopy (SEM) (1)
- Scarf joint (1)
- Scarf joint repair (1)
- Scarf joint repairs (1)
- Scavenging effect of iron (1)
- Schadenskunde (1)
- Schalenprüfstand (1)
- Schlickerdeposition (1)
- SchwarzP cells (1)
- Schwerelosigkeit (1)
- Schwingbrüche (1)
- Scratches (1)
- Screen printing (1)
- Screening method (1)
- Segregation (1)
- Segregation Engineering (1)
- Segregation engineering (1)
- Selective laser melting (SLM) (1)
- Self-Assembly (1)
- Self-organization (1)
- Semantic Data Integration (1)
- Semantic Interioerability (1)
- Semantic Web technologies (1)
- Semantic data integration (1)
- Semantic interoperability (1)
- Semantic structuring (1)
- Semantische Daten (1)
- Semiconductor materials (1)
- Sensing (1)
- Sensor (1)
- Serial sectioning (1)
- Serienschnitte (1)
- Sewage treatment plant (1)
- Shadowgraphy (1)
- Shape memory alloy (1)
- Shape memory alloys (1)
- Shear (1)
- Shear load (1)
- Shear strain (1)
- Shear testing (1)
- Shear thinning (1)
- Shear-band cavitation (1)
- Shear-band structure (1)
- Short range order (1)
- Short-beam strength (1)
- Silber (1)
- Silicate glass (1)
- Silicate glass-ceramics (1)
- Silicatglas (1)
- Silicoborate glasses (1)
- Silicon release (1)
- Silikatkeramik (1)
- Silver (1)
- Silver cluster (1)
- Silver glass paste (1)
- Silver precipitates (1)
- Silver-glass metallization paste (1)
- Simulation workflow (1)
- Simulationsgestützte Gießkonzepte (1)
- Single crystal Ni-Base superalloys (1)
- Single crystal superalloys (1)
- Single fiber pull-out test (1)
- Single-crystal (1)
- Sinter retardation (1)
- Sintering additive (1)
- Sintering atmosphere (1)
- Sintermechanismen (1)
- Sintertemperatur (1)
- Sinterung (1)
- Sinus floor augmentation (1)
- Size (1)
- Size and size distribution (1)
- Size effect (1)
- Sliding simulation (1)
- Slip localization (1)
- Slip-rolling (1)
- Slow Crack Growth (SCG) (1)
- Slurry optimization (1)
- Small angle x-ray scattering (1)
- Small-Angle X-ray Scattering (1)
- Small-scale (1)
- Smart materials (1)
- Smectite (1)
- Soda lime silicate glass (1)
- Soda-lime-silica (1)
- Sodium ion batteries (1)
- Sodium zinc borate glass (1)
- Sodiumborosilicate glasses (1)
- Softening temperature (1)
- Soil (1)
- Soil sample (1)
- Solar panels (1)
- Solid solution strengthening (1)
- Solid-State-Synthesis (1)
- Solid-state-synthesis (1)
- Solidification (1)
- Space exploration (1)
- Spar cap design (1)
- Spark plasma sintering (1)
- Specific surface (1)
- Specimen geometry (1)
- Spezifische Oberfläche (1)
- Spinodal Decomposition (1)
- Spinodal decomposition (1)
- Split Hopkinson bar (1)
- Split-vacancy defect complexes (1)
- Spring constant (1)
- Stable crack growth (1)
- Standardisation (1)
- Stanzen (1)
- Statistics (1)
- Steam oxidation resistance (1)
- Steel P92 (1)
- Steel alloy (1)
- Stereoscopy (1)
- Strain (1)
- Strain difference (1)
- Strain energy (1)
- Strain rate dependence (1)
- Stratégies deprévention (1)
- Stress distribution (1)
- Stress intensity (1)
- Stress-corrosion (1)
- Stress-strain behavior (1)
- Stress-strain-behavior (1)
- Streuung (1)
- Structural composites (1)
- Structural defects (1)
- Structural dynamics (1)
- Structural health monitoring (1)
- Structural health monitoring (SHM) (1)
- Structure (1)
- Structure property correlations (1)
- Structure-property correlation (1)
- Structured Data (1)
- Structured heating (1)
- Subcritical crack growth (1)
- Subsurface defects (1)
- Superaustenite steel (1)
- Supercritical/dense phase CO 2 (1)
- Superelasticity (1)
- Superlattice extrinsic stacking faults (1)
- Superlegierungen (1)
- Supersaturation (1)
- Support configurations (1)
- Support vector machines (1)
- Surface Nucleation (1)
- Surface elasticity (1)
- Surface modification (1)
- Surface roughness (1)
- Surface stress (1)
- Surface-induced Melting (1)
- Swept wavelength interferometry (1)
- Swept wavelength interferometry (SWI) (1)
- Symbolik (1)
- Synchrotron (1)
- Synchrotron CT (1)
- Synchrotron X-ray diffraction (1)
- Synchrotron micro-tomography (1)
- Synchrotron radiation (1)
- Synchrotron radiations (1)
- Synchrotron tomography (1)
- Synthesis (1)
- Systematische Schadensanalysen, Prozeduren (1)
- T1 precipitate (1)
- TAHYA (1)
- TED (1)
- TIG-welding (1)
- TMF experiments (1)
- Tb3+ (1)
- Technical Ceramics (1)
- Technische Keramik (1)
- Temperature dependence (1)
- Temperature driven process (1)
- Tempered martensite ferritic steel (1)
- Tempered martensite ferritic steels (1)
- Tensile strength (1)
- Tensile stress relaxation (1)
- Tensile stress relaxation testing (1)
- Tensile tests (1)
- Termites (1)
- Test Improvement (1)
- Tetragonal distortion (1)
- Tetragonality (1)
- Texturation (1)
- Theranostics (1)
- Thermal Cycling (1)
- Thermal cycling (1)
- Thermal degradation (1)
- Thermal desorption mass spectrometry (1)
- Thermal stress (1)
- Thermische Analyse (1)
- Thermo mechanical fatigue (1)
- Thermo-mechanical fatigue (1)
- Thermo-mechanical loading (1)
- Thermo-mechanical-loading (1)
- Thermo-mechanics (1)
- Thermo-optical measurement (1)
- Thermoanalysis (1)
- Thermoanalytical Methods (1)
- Thermobimetal (1)
- Thermodynamic analysis (1)
- Thermodynamic stability (1)
- Thermodynamische Stabilität (1)
- Thermoelectric generator (1)
- Thermoelectric generator design (1)
- Thermoelektrika (1)
- Thermoelektrischer Generator (1)
- Thermogravimetric analysis (1)
- Thermomechanical Fatigue (TMF) (1)
- Thermomechanische Eigenschaften (1)
- Thermomechanische Ermüdung (1)
- Thermophysikalische Eigenschaften (1)
- Thermoplastic forming (1)
- Thermoplastic matrix (1)
- Thermoplastic prepreg (1)
- Thermoset composition (1)
- Thermosetting resin (1)
- Thesaurus (1)
- Thickening (1)
- Thin films (1)
- Thin tribofilm (1)
- Thiol-ene click chemistry (1)
- Three-dimensional Bone tissue engineering (1)
- Three-dimensional tomographies (1)
- Time-offlight Diffraction (TOFD) (1)
- Tomography (1)
- Tools (1)
- Tooth wear (1)
- Transducers (1)
- Transformer (1)
- Transmission Kikuchi diffraction (1)
- Transmittance (1)
- Transparency (1)
- Transparent ceramic (1)
- Tribology (1)
- Tricalcium Phosphate (1)
- Triply Periodical Minimal Surface (1)
- Tungsten carbide (1)
- Tungsten-Rhenium (1)
- Turbine disk (1)
- Twinning (1)
- Two-photon adsorption (1)
- Two-photon polymerization (1)
- Two-photon-polymerization (1)
- Ultraschall (1)
- Ultrasonic Testing (1)
- Ultrasonic assited machining (1)
- Umgebungsbedingter Spannungsriss (1)
- Ungleichgewicht (1)
- Unidirectional composites (1)
- Unlegierter Baustahl (1)
- Upconversion nanoparticles (1)
- VCSEL (1)
- VM12 SHC (1)
- Vacancies (1)
- Vacuum hot extraction (1)
- Verbundwerkstoff (1)
- Verbundwerkstoffe (1)
- Vernetzung (1)
- Versetzungsstrukturen (1)
- Very high cycle fatigue (1)
- Vickers Hardness (1)
- Virtueller Materialdatenraum (1)
- Viscoelastic model (1)
- Viscose sintering (1)
- Viskoplastisch (1)
- Visual ontology development (1)
- Visualization (1)
- Vivianite (1)
- Vocabulary providers (1)
- Volatiles from thermosets (1)
- Volume Fraction (1)
- Volume changes (1)
- Volume fraction (1)
- WAXS (1)
- Wasserstoff (1)
- Wasserstofferzeugung (1)
- Waste water (1)
- Water (1)
- Water Diffusion (1)
- Water droplet erosion resistance (1)
- Water in glass (1)
- Welding processing influences (1)
- Werkstoffauswahl (1)
- Werkstoffdaten (1)
- Werkstoffkennwerte (1)
- Werkstoffmechanische Prüfung (1)
- Wet chemical etching (1)
- Wet dispersion (1)
- White light emitters (1)
- Wind turbine blade shell structures (1)
- Windkraft (1)
- Withstand voltage tests (1)
- Women in science (1)
- Work of adhesion (1)
- Workshop (1)
- Wärmespeicher (1)
- X-ray Diffraction (1)
- X-ray diffraction analysis (1)
- X-ray imaging (1)
- X-ray refractography (1)
- X-ray scattering (1)
- X-ray tomographic (1)
- X-ray-diffraction (1)
- XPCS (1)
- XRM (1)
- Young`s modulus (1)
- Young´s Modulus (1)
- Young´s modulus (1)
- Young’s Modulus (1)
- Yttria stabilized zirconia (1)
- ZfP (1)
- Zinc oxide (1)
- Zirconia-toughened alumina (1)
- Zirconia: yttria stabilized (1)
- ZnO (1)
- Zug-Druck-Schubprüfung (1)
- Zugversuchsontologie (1)
- Zyklische Belastung (1)
- Zyklische R-Kurve (1)
- alumina (1)
- arbidic austempered ductile iron (1)
- arbon capture (1)
- ausfgallfreie Lastwechsel (1)
- battery aging mechanism (1)
- bioactive (1)
- biomaterials (1)
- bone (1)
- carbon steel (1)
- ceramic (1)
- ceramics (1)
- coarsening (1)
- condensate (1)
- current collector corrosion (1)
- dental (1)
- depth profiles (1)
- dispersion (1)
- electrochemical characterization (1)
- electron microscopy (1)
- hardness (1)
- high entropy alloys (1)
- high pressure (1)
- hydrogen storage (1)
- impurities (1)
- in-situ synthesis (1)
- infrared spectroscopy (1)
- laser cladding (1)
- microstructural changes (1)
- microstructure analysis (1)
- multi scale testing (1)
- negative crystal growth (1)
- oxidation (1)
- particle size determination (1)
- phosphate glasses (1)
- pitting corrosion (1)
- sample preparation (1)
- scanning electron microscopy (1)
- selective laser melting (1)
- statistische Auswertung (1)
- sulfidation (1)
- thermomechanische Beanspruchung (1)
- utilization, and storage (CCUS) technology (1)
- volume resistivity (1)
- water speciation (1)
- zertifizierte Referenzmaterialien (1)
- Überblick (1)
- γ- и γ'-фазы, период кристаллической решетки (1)
- γ/γ' matrix (1)
- γ″ phase (1)
- θ′ phase (1)
- θ′-(Al2Cu) precipitate phase (1)
- высокие температуры (1)
- жаропрочные нике- левые сплавы (1)
- монокристалл (1)
- рентгеноструктурный анализ (1)
Organisationseinheit der BAM
- 5 Werkstofftechnik (1137)
- 5.1 Mikrostruktur Design und Degradation (338)
- 5.2 Metallische Hochtemperaturwerkstoffe (277)
- 5.4 Multimateriale Fertigungsprozesse (216)
- 5.6 Glas (151)
- 5.3 Polymere Verbundwerkstoffe (131)
- 5.5 Materialmodellierung (115)
- 8 Zerstörungsfreie Prüfung (107)
- 9 Komponentensicherheit (98)
- 7 Bauwerkssicherheit (91)
Paper des Monats
- ja (11)
Biomaterials for bone replacement and grafting should possess sufficient strength, be bioresorbable and demonstrate osteoconductivity/osteoinductivity. Nowadays, hydroxyapatite (HA) and tricalcium phosphate (TCP) are the most widespread ceramics for bone grafting at the market, however, their resorption is reported, in some cases, to be not enough. This is why the search for more soluble ceramics compared to HA and TCP looks rather viable.
A possible way to increase ceramics solubility leads to partial substitution of Ca2+-ions in Ca3(PO4)2 by alkali castions, like Na+ or/and K+. Improvement of solubility stems from decreasing lattice energy of a substituted phase, as well as increase in hydration energy of the ions releasing from the phase to ambient solution. From this viewpoint, bioceramics based on compositions from Ca3(PO4)2 - CaKPO4 - CaNaPO4 ternary system seems to be prospective for bone replacement and grafting in sense of resorption properties. At the same time, one should bear in mind that solubility level (resorbability) is governed not only by reduction of lattice energy, but also by microstructure features. Grain sizes and porosity contribute much to dissolution rate making study of sintering of aforementioned ceramics highly important.
A great amount of material properties is strongly influenced by dislocations, the carriers of plastic deformation. It is therefore paramount to have appropriate tools to quantify dislocation substructures with regard to their features, e.g., dislocation density, Burgers vectors or line direction. While the transmission electron microscope (TEM) has been the most widely-used equipment implemented to investigate dislocations, it usually is limited to the two-dimensional (2D) observation of three-dimensional (3D) structures. We reconstruct, visualize and quantify 3D dislocation substructure models from only two TEM images (stereo pairs) and assess the results. The reconstruction is based on the manual interactive tracing of filiform objects on both images of the stereo pair. The reconstruction and quantification method are demonstrated on dark field (DF) scanning (S)TEM micrographs of dislocation substructures imaged under diffraction contrast conditions. For this purpose, thick regions (> 300 nm) of TEM foils are analyzed, which are extracted from a Ni-base superalloy single crystal after high temperature creep deformation. It is shown how the method allows 3D quantification from stereo pairs in a wide range of tilt conditions, achieving line length and orientation uncertainties of 3% and 7°, respectively. Parameters that affect the quality of such reconstructions are discussed.
Hydrogen is an attractive energy carrier that requires high effort for safe storage. For ensuring safety, storage cylinders must undergo a challenging approval process. Relevant standards and regulations for composite cylinders used for the transport of hydrogen and for its onboard storage are currently based on deterministic (e.g. ISO 11119-3) or to some respect semi-probabilistic criteria (UN GTR No. 13; with respect to burst strength).
This paper provides a systematic analysis of the load cycle properties resulting from these regulations and standards. Their characteristics are compared with the probabilistic approach of the Federal Institute for Materials Research and Testing BAM. The most important aspect of comparing different concepts is the rate for accepting designs with potentially unsafe or critical safety properties. This acceptance rate is analysed by operating Monte-Carlo simulations over the available range of production properties.
In powder-based Additive Manufacturing (AM) processes, an object is produced by successively depositing thin layers of a powder material and by inscribing the cross section of the object in each layer. The main methods to inscribe a layer are by binder jetting (also known as powder 3D printing) or by selective laser sintering/melting (SLS/SLM).
Powder-based AM processes have found wide application for several metallic, polymeric and also ceramic materials, due to their advantages in combining flexibility, easy upscaling and (often) good material properties of their products.
The deposition of homogeneous layers is key to the reproducibility of these processes and has a direct influence on the quality of the final parts. Accordingly, powder properties such as particle size distribution, shape, roughness and process related properties such as powder flowability and packing density need to be carefully evaluated.
Due to these requirements, these processes have been so far precluded to find commercial use for certain applications. In the following, two outstanding cases will be presented.
A first example is that powder-based AM processes are widely used for many metallic and polymeric materials, but they find no commercial application for most technical ceramics.
This seemingly contradicting observation is explained by the fact that in powder based AM, a dry flowable powder needs to be used. The processing of technical ceramics in fact typically requires very fine and poorly flowable powder, which makes them not suitable for the standard processes. There have been several approaches to adapt the raw materials to the process (e.g. by granulation), but in order to maintain the superior properties of technical ceramics it seems necessary to follow the opposite approach and adapt the process to the raw materials instead.
This was the motivation for developing the Layerwise Slurry Deposition (LSD), an innovative process for the deposition of powder layers with a high packing density. In the LSD process, a ceramic slurry is deposited to form thin powder layers, rather than using a dry powder. This allows achieving high packing density (55-60%) in the layers after drying. It is also important, that standard ceramic raw materials can be used. When coupled with a printing head or with a laser source, the LSD enables novel AM technologies which are similar to 3D printing or selective laser sintering, but taking advantage of having a highly dense powder bed.
The LSD -3D printing, in particular, offers the potential of producing large (> 100 mm) and high quality ceramic parts, with microstructure and properties similar to traditional processing. Moreover, due to the compact powder bed, no support structures are required for fixation of the part in the printing process.
Figure 1 shows the schematics of the working principle of the LSD-3D print and illustrates some examples of the resolution and features achievable.
The second outstanding case here described is the application of powder-based AM in environments with reduced or zero gravity. The vision is to be able to produce repair parts, tools and other objects during a space mission, such as on the International Space Station (ISS), without the need of delivering such parts from Earth or carrying them during the mission. AM technologies are also envisioned to play an important role even for future missions to bring mankind to colonize other planets, be it on Mars or on the Moon. In this situation, reduced gravity is also experienced (the gravitational acceleration is 0.16 g on the Moon and 0.38 g on Mars).
These environments cause the use of AM powder technologies to be very problematic: the powder layers need to be stabilized in order to avoid dispersion of the particles in the chamber. This is impossible for standard AM powder deposition systems, which rely on gravitation to spread the powder.
Also in this case, an innovative approach has been implemented to face this technological challenge. The application of a gas flow through a powder has a very strong effect on its flowability, by generating a force on each particle, which is following the gas flow field. This principle can be applied in a simple setup such as the one shown in Figure 2.
In this setup, the gas flow causes an average pressure on the powder bed in direction of the arrows, generating a stabilizing effect which acts in the same direction of the gravitational force. This effect can be used in addition to normal gravity on Earth to achieve a better stabilization of 3D printed parts in the powder bed. In this case, even a significant increase of packing density of the powder was measured, compared to the same experimental setup without gas flow. This is due to the fact that the force on each single particle follows the gas flow field, which is guiding the particles to settle between the pores of the powder bed, thus achieving an efficient packing.
The same principle can be applied in absence of gravitation, where the gas flow acts to stabilize the powder layers. It has been shown that ceramic powder could be deposited in layers and laser sintered in µ-gravity conditions during a DLR (Deutsches Zentrum für Luft- und Raumfahrt) campaign of parabolic flights, as shown in Figure 2. A follow-up campaign is dedicated to the deposition of metallic (stainless steel) powder in inert atmosphere and to study the effects of laser melting in µ-gravity.
In conclusion, the description of these two example cases shows how the development of novel technological processes can address some of the limitations of standard powder-based AM, in order to enable the use of new materials, such as technical ceramics, or to tackle the challenges of AM in space.
Powder bed -based technologies are amongst the most successful Additive Manufacturing (AM) techniques. "Selective laser sintering/melting" (SLS/SLM) and "binder jetting 3D printing" (3DP) especially are leading AM technologies for metals and polymers, thanks to their high productivity and scalability. In this context, the "layerwise slurry deposition" (LSD) has been developed as a layer deposition method which enables the use of SLS/SLM and 3DP technologies for advanced ceramic materials. LSD consists in the layer-by-layer deposition of a ceramic slurry by means of a doctor blade. Each layer is deposited and dried to achieve a highly packed powder layer, which can be used for SLM or for 3DP. This technique offers high flexibility in the ceramic feedstock used, especially concerning material and particle size, and is capable of producing parts with physical and mechanical properties comparable to traditionally shaped parts. In this presentation, the LSD technique will be introduced and several examples of application to porcelain, SiC and alumina products will be reported.
Carbon Capture and Storage (CCS) is identified as an excellent technology to reach the target of CO2 reduction. However, the safety issue and cost effectiveness hinder the future of CCS. For the reliability and safety issues of injection wells the corrosion resistance of the materials used needs to be determined.
In this study, representative low cost materials including carbon steel 1.8977 and low alloyed steel 1.7225 were embedded in cement to mimic the realistic casing-cement interface. Electrochemical studies were carried out using these metal-cement specimens in comparison with those made of metal only in CO2 saturated synthetic aquifer fluid, at 333 K, to reveal the effect of cement on the steel performance. The results showed the protective effect of cement on the performance of pipeline metals during polarisation process. However, the corrosion current density was high in all cases, with and without cement, indicating that the corrosion resistance of these materials is low. This conclusion was supported by the surface analysis of the polarized specimens, which revealed both homogenous and pitting corrosions.
Carbon Capture and Storage (CCS) is identified as an excellent technology to reach the target of CO2 reduction. However, the safety issue and cost effectiveness hinder the future of CCS. For the reliability and safety issues of injection wells the corrosion resistance of the materials used needs to be determined.
In this study, representative low cost materials including carbon steel 1.8977 and low alloyed steel 1.7225 were embedded in cement to mimic the realistic casing-cement interface. Electrochemical studies were carried out using these metal-cement specimens in comparison with those made of metal only in CO2 saturated synthetic aquifer fluid, at 333 K, to reveal the effect of cement on the steel performance. The results showed the protective effect of cement on the performance of pipeline metals during polarisation process. However, the corrosion current density was high in all cases, with and without cement, indicating that the corrosion resistance of these materials is low. This conclusion was supported by the surface analysis of the polarized specimens, which revealed both homogenous and pitting corrosions. Furthermore, to reveal the possible protective performance of FeCO3, the pipeline steels were pre-carbonated and then tested in the same condition as freshly polished specimens.
Entwickelt wurde eine mehrstufige Fertigungstechnologie (Schruppen, Schlichten, Trennschnitt) zur Herstellung keramischer Federn aus gesinterten Hohlzylindern. Durch Optimierung von Maschinenparametern, Schleifscheiben sowie Werkstück- und Werkzeugaufnahmen ist es gelungen, Federn aus Hochleistungskeramik (Aluminiumoxid und Zirkonoxid) mit hoher Kanten- und Oberflächenqualität reproduzierbar herzustellen. Eine hohe Variabilität bezüglich Außen- und Innendurchmesser, Steigung, Windungsquerschnitt und Abstand zwischen den Windungen ermöglicht es, die Federkonstante über drei Größenordnungen zu variieren.
Untersucht wurden Federstabilität und Spannungs-Dehnungs-Verhalten unter konstanter und zyklischer Druckbelastung sowie die thermomechanische Stabilität der Keramikfedern. Aluminiumoxid-Federn können bis etwa 800°C, Zirkonoxid-Federn bis etwa 600°C ohne bleibende geometrische Verformung eingesetzt werden.
Unter konstanter Spannung zeigen Federn aus Y-stabilisiertem TZP (Zirkonoxid)-Werkstoffen, von anderen Keramikwerkstoffen abweichend, bei Raumtemperatur eine zeitabhängige, elastische, Verformung (Superelastizität), die nach Entlastung über einen Zeitraum von mehreren Stunden reversibel verläuft. Als Ursache wird eine spannungsinduzierte reversible Phasenumwandlung zwischen austenitischer (tetragonales ZrO2) und martensitischer (monoklines ZrO2) Phase postuliert.
Diskutiert wird das Anwendungspotenzial der entwickelten Federn für kapazitive keramische Federsensoren für Gravimeter und Wägetechnik.
The granules commonly yielded by spray drying procedures exhibit a hard shell and an irregular, dimpled shape, which is often described as donut-like morphology. Sintered parts produced from such granules suffer from microstructural defects and reduced mechanical properties resulting from these disadvantageous granule properties.
Using the example of alumina, zirconia and zirconia-toughened alumina (ZTA) batches, this paper shows that the morphology of the granules can be tuned by adjusting slurry stability. High zeta potential is essential to optimally disperse the particles. But to achieve spherical and soft granules the electrostatic repulsion forces between the particles should be reduced before spray granulation. Electrostatic repulsion forces were changed with the addition of nitric acid. Measurements of zeta potential and viscosity, as well as sedimentation investigations with an optical centrifuge were used for precise slurry assessment as a major precondition for optimal and reproducible adjustment of slurries before spray drying. Sedimentation analysis using an optical centrifuge was performed to investigate different influences like that of additive composition, solids content or pH-value on the sedimentation behavior. Adequately flocculated slurries lead to homogeneous, soft granules that can be easily deformed and pressed. The fraction of donut-shaped particles and the rigidity of granules were reduced. Consequently, the sintered parts produced from these granulates show improvements regarding porosity, pore size distribution, sintered density and biaxial strength.
A wide range of solid-state synthesis routes for calcium manganate is reported in the literature, but there is no systematic study about the influence of the solid-state synthesis conditions on thermoelectric properties. Therefore, this study examined the influence of calcination temperature and calcination cycles on the Seebeck coefficient, electrical conductivity, and thermal conductivity. Higher calcination temperatures and repeated calcination cycles minimized the driving force for sintering of the synthesized powder, leading to smaller shrinkage and lower densities of the sintered specimens. As the electrical conductivity increased monotonously with increasing density, a higher energy input during calcination caused deterioration of electrical conductivity. Phase composition and Seebeck coefficient of sintered calcium manganate were not influenced by the calcination procedure. The highest thermoelectric properties with the highest power factors and figures of merit were obtained by means of reaction-sintering of uncalcined powder.
The fundamental impact of sulfur and water on corrosion rates and potential failure of the exposed material is well known. However, the access to the related corrosion mechanism causing material degradation is often a problem to solve. This study investigates the effect of SO2 and water vapor in the initial stages of corrosion of an Fe9Cr0.5Mn model alloy at 650 °C in situ. The analysis was carried out under laboratory conditions using energy-dispersive X-ray diffraction (EDXRD).
The influence of heat treatment and creep loading on the microstructure of an Al-Cu-Li alloy was investigated. Especially the formation of different precipitates (T1 and Theta') were characterized and the microstructural changes under different ageing conditions (with and without external strain) were investigated to determine the effect od stress on the ageing process.
The influence of heat treatment and creep loading on the microstructure of an Al-Cu-Li alloy was investigated. Especially the formation of different precipitates (T1 and Theta') were characterized and the microstructural changes under different ageing conditions (with and without external strain) were investigated to determine the effect od stress on the ageing process.
High-performance composites, including glass-fiber reinforced plastic (GFRP) materials, are favored as a construction material for wind turbine rotor blades due to their high specific strength and stiffness properties. During the manufacturing process, however, imperfections are often introduced, then further propagated due to harsh environmental conditions and a variety of loads. This leads to failure significantly before their projected 20-year lifespan. As replacement of entire blades can be a costly potential outcome, localized repair of the damaged region to restore structural integrity and thus lengthen its lifespan has become an important issue in recent years. Rotor blades are often repaired using a common technique for composite laminates: adhesively bonded structural repair patches. These methods involve replacing the lost load path with a new material that is joined to the parent structure, and include scarf or plug repairs. However, there currently do not exist any standardized repair procedures for wind turbine rotor blades, as comparisons of blade properties repaired with the existing methods have not been studied in depth. Namely, there is a lack of understanding about the effects of various repair methods on the fatigue life of the shells of rotor blades. This study therefore aims to begin to fill this knowledge gap by testing the influence of different repair patches on the blades’ mechanical properties. Manufactured with the vacuum-assisted resin infusion process, the test specimens are produced as a curved structure with GFRP sandwiching a polyvinyl chloride foam core to best represent a portion of a rotor blade shell. Scarf repairs are then introduced with varying layup techniques, and material properties are examined with cyclical fatigue tests. Crack growth and development is monitored during fatigue testing by various non-destructive testing methods, including passive thermography with an infrared camera system, and a 3D deformation analysis system with ARAMIS. Large deformation fields and detection of in- and out-of-plane deformations is thus possible in-situ. The mechanical behavior and development of defects in the various repaired specimens is compared to each other as well as to reference test specimens with no repair patches. In-situ test data is combined with further non-destructive testing methods, including laminography, and active thermography, to develop a robust understanding of the effects of repair concepts.
Effects of various geometrical and physical factors, as well as the method of data reduction (analysis of
experimental forceedisplacement curves) on the values of local interfacial strength parameters (local IFSS, td, and critical energy release rate, Gic) determined by means of a single fiber pull-out test are discussed. Experimental results of our pull-out tests on several fiberepolymer matrix systems showed that td and Gic weakly depended on geometrical factors. However, the pull-out test appeared to be sensitive to the conditions of specimen formation and testing, such as changing the nature of the contacting surfaces (fiber sizing) and the fiber pull-out rate. Of several methods of td and Gic Determination from a forceedisplacement curve, the most reliable and reproducible one is the approach based on the values of the maximum force recorded in a pull-out test and the interfacial frictional force immediately after fiber debonding.
Der Vortrag zeigt zwei Möglichkeiten zur Verbesserung der VSSA-Screening-Methode zur Identifizierung von Nanopulvern auf. Bisher ist das Verfahren nur für monodisperse Partikel mit idealer Kugelform valide. Die Verteilungsbreite der Partikelgröße soll durch die Nutzung des Modells einer logarithmischen Normalverteilung implementiert werden. Die Abweichung der gemessenen Partikel von einer idealen Kugel in Sphärizität, Rundheit und Rauigkeit sind über einen Morphologiefaktor MF zu berücksichtigen. An einem konkreten Beispiel werden Auswirkungen der Implementierungen rechnerisch dargestellt und mit dem bisherigen Verfahren verglichen.
Materials subjected to high-temperature service conditions will change their microstructure with time. Associated with this aging process is a change of mechanical properties as well as a change of damage mechanisms. Within the scope of the FVV project Aging and Lifetime, Fraunhofer IWM in Freiburg and BAM in Berlin (both Germany) experimentally characterized the widespread high-temperature aluminum alloy EN AW-2618A in different overaging states. Based on the experimental findings, models for numerical lifetime assessment with the finite-element method were implemented.
Werkstoffe im Hochtemperatureinsatz verändern mit der Zeit ihre Mikrostruktur. Mit diesem Alterungsprozess einher geht eine Veränderung der mechanischen Eigenschaften ebenso wie eine Veränderung des Schädigungsverhaltens. Im Rahmen des FVV Vorhabens „Alterung und Lebensdauer“ haben das Fraunhofer IWM in Freiburg und die BAM in Berlin die weit verbreitete warmfeste Aluminiumlegierung EN AW-2618A in verschiedenen Alterungszuständen experimentell charakterisiert und darauf aufbauend Modelle für die Lebensdauerbewertung mit der Finite-Elemente- Methode implementiert.
Ni-base superalloy single crystals have been used in turbine blades for hot sections of gas turbines for over four decades. In order to increase the efficiency of the turbines, a continuous increase in the inlet temperature of combustion gases into the turbine has driven the design of turbine blades to complicated shapes and the presence of a complex pattern of cooling channels. These three-dimensional shapes, together with the inhomogeneous distribution of stresses along the blade, induce an also complicated triaxial stress state, which does not compare to uniaxial tests that are performed to characterize high temperature properties such as creep. A round notch on a test piece represents a simple configuration that generates a quasi-isostatic stress state across the notch. In the present contribution, the effect of a sharp round notch on the microstructural micromechanisms within the notched region cylindrical bars, loaded along [001] at 1020 °C and 160 MPa net stress, is studied. To this end, a series of interrupted creep tests is conducted on plain and notched bars and the microstructure is compared. Results are discussed in terms of degree microstructural coarsening, and dislocation activity. The effect of notch generation via grinding is also discussed in these terms. The presence of carbides evolving in from residual carbon is also shown and discussed. .Funding by the German Research Association (DFG) [grant number AG 191/1] is acknowledge
Due to their excellent combination of ductility, strength and corrosive resistance, austenitic stainless steels (ASS) are widely used in many industrial applications. Thus, these steel grades can be found as structural components in the (petro-)chemical industry, in offshore applications and more recent for storage and transport of hydrogen fuel. Steels employed for these applications are exposed to aggressive environments and hydrogen containing media. The ingress and accumulation of hydrogen into the microstructure is commonly observed during service leading to a phenomenon called “hydrogen embrittlement”. A loss in ductility and strength, the formation of cracks and phase transformations are typical features of this hydrogen-induced degradation of mechanical properties.
Although, great efforts are made to understanding hydrogen embrittlement, there is an ongoing debate of the underlying mechanisms. This knowledge is crucial for the safe use and durability of components on the one side and the development of new materials on the other.
Time-of-flight secondary ion mass spectrometry (ToF-SIMS) was proven to be a powerful tool for depicting the distribution of the hydrogen isotope deuterium in the microstructure of austenitic and duplex steels. The combination with imaging techniques such as electron backscatter diffraction (EBSD) and scanning electron microscopy (SEM), delivering structural and morphological information, creates a comprehensive picture of the hydrogen/deuterium-induced effects in the materials. All the gathered data is treated with principal component analysis (PCA) and data fusion to enhance the depth of information.
The mobility of hydrogen and deuterium in a steel microstructure is affected by external mechanical stress. To investigate the behaviour of deuterium in a strained microstructure, a new in situ experimental approach was developed. This gives the possibility of analysing samples in the SIMS instrument simultaneously to four-point-bending-tests.
Specimens made from ASS AISI 304L were electrochemically charged with deuterium instead of hydrogen. This necessity stems from the difficulty to separate between artificially charged hydrogen and hydrogen existing in the pristine material or adsorbed from the rest gas in the analysis chamber. Nonetheless, similar diffusion, permeation and solubility data allow to draw qualitative conclusions from the experiments, which are relevant for the application addressed.
Hochleistungsverbundwerkstoffe, bzw. Glasfaser-Kunststoff-Verbunde (GFK), haben sich als Leichtbauwerkstoffe für Leichtflugzeuge und Rotorblätter von Windkraftanlagen etabliert. Die hohe spezifische Festigkeit und Steifigkeit qualifizieren sie besonders für diese Anwendung. Während der Fertigung werden Imperfektionen häufig in die Blattschalen eingebracht. Durch Witterungseinflüsse kommt es zum Schadensfortschritt. Infolgedessen treten Schäden in der Blattschale, die den sicheren Betrieb gefährden können, weit vor der projektierten Lebensdauer von 20 Jahren auf. Da der Austausch von ganzen Blättern sehr kostintensiv ist, ist eine lokale Reparatur des geschädigten Bereichs zur Wiederherstellung der strukturellen Integrität, viel preisgünstiger. Die Reparatur von Rotorblättern ist in den letzten Jahren zu einem wichtigen Thema geworden. Derzeit werden verschiedenste Reparaturkonzepte angewendet. Eine einheitliche Reparaturvorgabe gibt es bisher nicht. Die Auswirkungen der angewendeten Reparaturkonzepte auf die Betriebsfestigkeit der Reparaturstelle sind weitestgehend unbekannt und sollen deshalb in diesem Projekt untersucht werden. Gekrümmte Voll-Laminat sowie Sandwich Prüfkörper werden mit dem Vacuum-Assisted-Resin-Infusion-Prozess (VARI) produziert. Um einen Teil einer Rotorblattschale darzustellen, sind sie als GFK aufgebaut, beziehungsweise die Sandwich Strukturen mit einem Polyvinylchlorid-Schaumkern (PVC) Kern, wie im Original. Schalenreparaturen in verschiedenen Layup-Techniken und Geometrie werden eingebracht und die Materialeigenschaften mit zyklischen Ermüdungstests untersucht. Im Projekt werden ideal im Labor erzeugte Reparaturstellen mit in der Praxis angewendeten Ausführungstechniken eines Industriepartners experimentell verglichen. Für die in-situ Detektion der Schadensentwicklung während des Ermüdungsversuches kommt ein kombiniertes Felddehnungs- und Thermografie-Kamerasystem zum Einsatz. Das mechanische Verhalten und die Schadensentwicklung in den verschiedenen reparierten Prüfkörper wird miteinander sowie mit den Referenzproben ohne Reparaturstellen verglichen. Zudem wird in numerischen Modellen für die verschiedenen Reparaturtechniken eine Spannungsanalyse durchgeführt um hinsichtlich der Betriebsbeanspruchung eine Bewertung angeben zu können.
The creep behavior of single-crystals of the nickel-base superalloy CMSX-4 was investigated at 1288°C, which is the temperature of the hot isostatic pressing (HIP) treatment applied to this superalloy in the industry. It was found that at this super-solvus temperature, where no Gamma’-strengthening occurs, the superalloy is very soft and rapidly deforms under stresses between 4 and 16 MPa. The creep resistance was found to be very anisotropic, e.g. the creep rate of [001] crystals was about 11 times higher than that of a [111] crystal. The specimens of different orientations also showed a very different necking behavior. The reduction of the cross-section area psi of [001] crystals reached nearly 100%, while for a [111] crystal psi=62%. The EBSD analysis of deformed specimens showed that despite such a large local strain the [001] crystals didn’t not recrystallize, while a less deformed [111] crystal totally recrystallized within the necking zone. From the shape of deformed specimens and TEM investigations it was concluded that the main strain contribution resulted from <011> {111} octahedral slip.
Additive Manufacturing (AM) through the Selective Laser Melting (SLM) route offers ample scope for producing geometrically complex parts compared to the conventional subtractive manufacturing strategies. Nevertheless, the residual stresses which develop during the fabrication can limit application of the SLM components by reducing the load bearing capacity and by inducing unwanted distortion, depending on the boundary conditions specified during manufacturing. The present study aims at characterizing the residual stress states in the SLM parts using different diffraction methods. The material used is the nickel based superalloy Inconel 718. Microstructure as well as the surface and bulk residual stresses were characterized.
For the residual stress analysis, X-ray, synchrotron and neutron diffraction methods were used. The measurements were performed at BAM, at the EDDI beamline of -BESSY II synchrotronand the E3 line -BER II neutron reactor- of the Helmholtz-Zentrum für Materialien und Energie (HZB) Berlin. The results reveal significant differences in the residual stress states for the different characterization techniques employed, which indicates the dependence of the residual state on the penetration depth in the sample. For the surface residual stresses, longitudinal and transverse stress components from X-ray and synchrotron agree well and the obtained values were around the yield strength of the material. Furthermore, synchrotron mapping disclosed gradients along the width and length of the sample for the longitudinal and transverse stress components. On the other hand, lower residual stresses were found in the bulk of the material measured using neutron diffraction. The longitudinal component was tensile and decreased towards the boundary of the sample. In contrast, the normal component was nearly constant and compressive in nature. The transversal component was almost negligible. The results indicate that a stress re-distribution takes place during the deposition of the consecutive layers. Further investigations are planned to study the phenomenon in detail.
We invented the first non-metallic, self-adhesive and dry biosignalling electrode. The PEDOT polymer electrode changes its aggregate state and conductivity by a light curing procedure. The electrode can be applied as a gel underneath hair without shaving. With the aid of blue light, the electrode can be hardened within a few seconds at the desired location on the scalp. The cured polymer electrode is highly conductive and can be applied on a very small location. Unlike other EEG electrodes, our electrode does not lose conductivity upon drying. Furthermore, our electrode strongly bonds to Skin and does not require any additional adhesive. Short circuits due to an outflow of gel are prevented with this technique. Therefore, the PEDOT polymer electrode is extremely well suited for applications that, up to now, have been challenging, such as non-invasive EEG recordings from awake and freely moving animals, EEG recordings from preterm babies in the neonatal intensive care unit or long-term recordings in the case of sleep monitoring or epilepsy diagnostics. We addressed two technical questions in this work. First, is the EEG recorded with polymer electrodes comparable to a standard EEG? Second, is it possible to record full-band EEGs with our electrodes?
Additive Manufacturing (AM) through the Selective Laser Melting (SLM) route offers ample scope for producing geometrically complex parts compared to the conventional subtractive manufacturing strategies. Nevertheless, the residual stresses which develop during the fabrication can limit application of the SLM components by reducing the load bearing capacity and by inducing unwanted distortion, depending on the boundary conditions specified during manufacturing. The present study aims at characterizing the residual stress states in the SLM parts using different diffraction methods. The material used is the nickel based superalloy Inconel 718. Microstructure as well as the surface and bulk residual stresses were characterized. For the residual stress analysis, X-ray, synchrotron and neutron diffraction methods were used. The measurements were performed at BAM, at the EDDI beamline of -BESSY II synchrotronand the E3 line -BER II neutron reactor- of the Helmholtz-Zentrum für Materialien und Energie (HZB) Berlin. The results reveal significant differences in the residual stress states for the different characterization techniques employed, which indicates the dependence of the residual state on the penetration depth in the sample. For the surface residual stresses, longitudinal and transverse stress components from X-ray and synchrotron agree well and the obtained values were around the yield strength of the material. Furthermore, synchrotron mapping disclosed gradients along the width and length of the sample for the longitudinal and transverse stress components. On the other hand, lower residual stresses were found in the bulk of the material measured using neutron diffraction. The longitudinal component was tensile and decreased towards the boundary of the sample. In contrast, the normal component was nearly constant and compressive in nature. The transversal component was almost negligible. The results indicate that a stress re-distribution takes place during the deposition of the consecutive layers. Further investigations are planned to study the phenomenon in detail.
A femto-second pulsed laser ablation in liquid (PLAL) procedure for the generation of titanium oxide nanoparticles (NP) is reported with the purpose of understanding morphology and structure of the newly generated NPs. Ablation duration was varied for optimization of NP generation processes between 10 and 90 min. Surface morphology of NPs as well as their size and shape (distribution) were analysed by various complementary electron microscopy techniques, i.e. SEM, TSEM and TEM. The crystalline structure of titanium oxide particles was investigated by XRD(two instruments operated in different geometries) and HR-TEM. Concentration of generated titanium oxide NPs in liquid was analysed by ICP-MS. A mix of crystalline (mainly anatase), partly crystalline and amorphous spherical titanium oxide NPs can be reported having a mean size between 10 and 20 nm, which is rather independent of the laser ablation (LA) duration. A second component consisting of irregularly shaped, but crystalline titanium oxide nanostructures is co-generated in the LA water, with more pronounced occurrence at longer LA times. The provenance of this component is assigned to those spherical particles generated in suspension and passing through the converging laser beam, being hence subject to secondary irradiation effects, e. g. fragmentation.
A numerical pre-study has shown that cracks in a flat sample featuring a drilled hole can be classified into one of three crack shape classes based on the combined evaluation of various types of test data.
Efficient energy provision using fuel cells requires effective hydrogen storage capacities. Glass is a material of low intrinsic hydrogen permeability and is therefore a promising material for hydrogen storage containers or diffusion barriers. Pioneer work on oxidic glasses seems to indicate a correlation between glass composition and hydrogen permeation, which was mainly derived from the behavior of silica glass. In this study, we focus on the relationship between topologic (free volume; network polymerization) and thermodynamic (configurational entropy) glass parameters. Experiments were performed well below the glass transition temperature, which excludes significant structural relaxation and chemical dissolution of hydrogen. The compositional dependence of seven glasses on the SiO2-NaAlO2 join pointed out that in fully polymerized glasses the H2 permeability cannot be solely derived from the total free volume of the glass structure. Hence, evidence is provided that the size distribution of free volume contributes to hydrogen diffusion and solubility. Additionally, results indicate that hydrogen permeability of the glasses is affected by the configurational heat capacity ΔCp at Tg.
Effective hydrogen storage capacities are prerequisite for an efficient energy provision using fuel cells. Since glass has low intrinsic hydrogen permeability, it is a promising material for hydrogen storage containers as well as hydrogen diffusion barriers. Previous studies on oxidic glasses suggest a correlation between the glass composition and hydrogen permeation that was derived mainly from silica glass. In the present study, we concentrate on the relationship between thermodynamic (i.e., configurational entropy) and topologic (i.e., free volume, network polymerization) parameters. Experimental data were gathered well below the glass transition temperature, excluding significant effects caused by structural relaxation and chemical dissolution of hydrogen. The results of seven analysed glasses on the SiO2-NaAlO2 joint showed that the hydrogen permeability in fully polymerized glasses cannot solely be derived from the total free volume of the glass structure. Hence, evidence is provided that the size distribution of free volume contributes to hydrogen solubility and diffusion. Additionally, the results indicate that the configurational heat capacity ΔCp at Tg affects the hydrogen permeability of the investigated glasses.
PE-HD as a polymeric fuel storage tank material: Photooxidation, fuel sorption and long-term storage
(2018)
High-density polyethylene (PE-HD) is a commodity thermoplastic polymer which is typically used for packing of dangerous goods. Its good resistance against photooxidation, fuels, chemicals and other environmental factors in addition to low production costs makes PE-HD attractive for fuel storage applications. Typical engine fuels stored in polymer tanks are petrol, diesel and biodiesel that receives increasing attention as proper alternative to fossil fuels. One of the major problems with biodiesel is its susceptibility to oxidize due to its chemical composition of unsaturated fatty acids which also can cause polymer degradation.
The aim of this study is to investigate the influence of different environmental factors, UV radiation and commonly stored fuels, on the mechanical, physical and chemical properties of two types of PE-HD polymers (stabilized and non-stabilized). The influence on the mechanical properties was tested by Charpy and tensile tests, chemical and physical properties were evaluated by Fourier-transform infrared spectroscopy (FTIR) and by dynamical mechanical analysis (DMA) tests. Samples were characterized after varying exposure time of UV radiation and after fully and partially immersion in biodiesel. In addition, similar experiments were conducted using diesel for comparison.
The first documentation of fuel biodeterioration dates back to the late 19th century. However, extensive studies concerning the microbial fuel contamination started in 1980’s. Polymeric fuel storage tanks containing diesel and biodiesel provide environmental conditions for microbial growth. Several studies demonstrated that bacteria, which were found in contaminated fuel systems, can use fuels as macronutrient; but such bacteria can also cause microbiologically influenced corrosion and fouling.
The aim of this study is to investigate the initial attachment behavior of bacteria, isolated from a diesel contamination, on neat and photooxidized high-density polyethylene (PE-HD). Two common PE-HD’s, less- and biodiesel-stabilized, were radiated to UV light representing a tank exposed to sunlight. The effect of photooxidiation on PE-HD’s surface were characterized chemically by Fourier-transform infrared spectroscopy (FTIR). The attached bacteria Pseudomonas aeruginosa and Bacillus subtilis on the polymer surface were evaluated by fluorescence microscopy and colony-forming unit tests (CFU).
Glass-fibre-reinforced plastics (GFRP) are commonly used for the construction of pressure vessels and tanks for example in automotive and aerospace industries. Especially for pressure vessels used for the storage of natural gas or hydrogen with operation pressures up to 700 bar, an early material fatigue detection is of great interest. Measuring the distributed strain profile of GFRP structures helps to understand and detect material fatigue. In this article, we demonstrate the great potential of swept wavelength interferometry (SWI) based distributed strain sensing for the monitoring of pressure vessels made from GFRP. A resin transfer molding (RTM) process was used to manufacture GFRP-tube specimens. Commercial optical fibres with polyimid coating were glued to the surface externally in circumferential and axial direction. A cyclic load of up to 150 bar was applied to the samples using a servo-hydraulic test bench. Comparing the loaded and unloaded test conditions, we determined up to 2 % elongation in circumferential direction. We demonstrate reliable distributed strain measurements with sub-centimetre spatial resolution. By monitoring these high-resolution strain profiles, we were able to detect local material degradation that manifested itself as localized strain changes. Crucially, the material Degradation could be detected already after 75 % of dat the fatigue life before a crack appeared that led to leakage.
This study examines the relationship between the magnetic mesostructure with the microstructure of low carbon steel tungsten inert gas welds. Optical microscopy revealed variation in the microstructure of the parent material, in the heat affected and fusion zones, correlating with distinctive changes in the local magnetic stray fields measured with high spatial resolution giant magneto resistance sensors. In the vicinity of the heat affected zone high residual stresses were found using neutron diffraction.
Notably, the gradients of von Mises stress and triaxial magnetic stray field modulus follow the same tendency transverse to the weld. In contrast, micro-X-ray fluorescence characterization indicated that local changes in element composition had no independent effect on magnetic stray fields.
Lock-in- and flash thermography are standard methods in active thermography. They are widely used in industrial inspection tasks e.g. for the detection of delaminations, cracks or pores. The requirements for the light sources of these two methods are substantially different. While lock-in thermography requires sources that can be easily and above all fast modulated, the use of flash thermography requires sources that release a very high optical energy in the very short time.
By introducing high-power vertical cavity surface emitting lasers (VCSELs) arrays to the field of thermography a source is now available that covers these two areas. VCSEL arrays combine the fast temporal behavior of a diode laser with the high optical irradiance and the wide illumination range of flash lamps or LEDs and can thus potentially replace all conventional light sources of thermography.
However, the main advantage of this laser technology lies in the independent control of individual array areas. It is therefore possible to heat not only in terms of time, but also in terms of space. This new degree of freedom allows the development of new NDT methods. We demonstrate this approach using a test problem that can only be solved to a limited extent in active thermography, namely the detection of very thin, hidden defects in metallic materials that are aligned vertically to the surface. For this purpose, we generate destructively interfering thermal wave fields, which make it possible to detect defects within the range of the thermal wave field high sensitivity. This is done without pre-treatment of the surface and without using a reference area to depths beyond the usual thermographic rule of thumb.
In Germany spent nuclear fuel and high level radioactive waste is stored in interim storage containers with double lid systems. Those lids are equipped with metal seals (e.g. Helicoflex®) that ensure the safe enclosure of the inventory. The used metal seals consist of three components as can be seen in the cross-sectional view in Figure 1. The innermost part is a helical spring that is surrounded by an inner jacket made of stainless steel. The outer jacket that is made of a softer material which in case of assembly in the aforementioned storage containers is silver or aluminum (i.e. Al 99.5). During application the seal is compressed and due to the restoring force of the helical spring, the outer jacket is plastically deformed and adapts to the sealing surface. Hence, leakage paths are closed and the sealing function is generated. In Germany the above-mentioned containers are licensed for up to 40 years of interim storage, which in case extended storage becomes necessary before a final repository is available will have to be extended to even longer periods. Therefore, the evaluation of the long-term behavior of the seals is necessary, taking into account storage conditions, decay heat and possible mechanical loads as well.
At Bundesanstalt für Materialforschung und –prüfung (BAM) long-term investigations are being conducted in which seals are assembled in test flanges and aged at temperatures ranging from room temperature to 150°C for accelerated aging. The aged seals are tested semi-annually (after the first 6 months in which the seals are tested more frequently) regarding the sealing performance, the remaining seal force, and the useable resilience upon decompression. Results of these investigations have been published over the past years (e.g. Grelle, Wolff, Probst, Jaunich, & Völzke, 2017; Völzke, Wolff, Probst, Nagelschmidt, & Schulz, 2014). It was found that the seal force and the useable resilience decrease with time and temperature, which is in agreement with the result of other studies (Sassoulas et al., 2006; Wataru et al., 2016) as well. Geometry change of the outer jacket has been identified as the main reason for this seal behavior. At the prevailing operating temperatures and stresses the aluminum is subjected to creep deformation leading to a thinning of the outer jacket. Since the seal groove depth remains unchanged the helical spring expands, which in turn leads to a decrease of the generated spring and seal force.
Although the main reason for the change of seal parameters over time and temperature is known, a detailed characterization of the seal behavior and a reliable prediction of the parameter development for aging times that exceed the experimental time frame have not been possible, yet.
For deeper understanding of the aging processes, an Investigation program, which is covered in this contribution, is conducted at Bundesanstalt für Materialforschung und –prüfung (BAM) that focusses on the behavior of the aluminum jacket and its influence on the long-term sealing performance. The program investigates properties of material samples as well as the behavior of the seal as a component.
Original sheet material of the same aluminum that is used for manufacturing of the seals is investigated in compression creep tests. For this, a DMA (dynamic mechanical analysis) machine is employed (here used for static tests) that allows for a measurement of the specimens deformation under forces of up to 500 N. The advantage of this method is that the original material can be tested in the same shape as used for the seals which is 0.5 mm thick sheet material. For investigation of tensile creep standard specimens are used, that were machined from surrogate material of the same composition and annealing condition.
Furthermore, aluminum seals that are cut into smaller segments are assembled in flanges and placed in heating chambers at temperatures ranging from 23°C to 150°C. After different periods of time from 3 days to 300 days the segments are taken out of the flanges and are investigated, thus giving information on different states of aging. Measurements of the development of the seal contact width and the aluminum jacket thickness are done with an optical microscope. Further investigations on the segments will include metallography and hardness measurements.
From the detailed material and component behavior including the results of the long-term seal force and useable resilience investigations a better understanding of the overall seal behavior can be gained. The aim is to contribute to the development of material models and analytical approaches for the prediction of the sealing behavior in dependence of time and temperature.
In Germany spent nuclear fuel (SNF) and high level radioactive waste (HLW) are stored in interim storage containers with double lid systems. Those lids are equipped with metal seals (e.g. Helicoflex®) that ensure the safe enclosure of the inventory. Being licensed for up to 40 years of interim storage the evaluation of the long-term behavior of the seals is necessary, taking into account storage conditions, decay heat and possible mechanical loads.
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.
Most additive manufacturing processes which produce dense ceramics are nowadays limited in size because of inevitable post-processing steps like for example binder removal in stereolithography. The additive manufacturing of voluminous ceramic parts is realized by powder bed based processes which, however, generate parts with residual porosity. Via infiltration these parts can be processed to dense parts like for example SiC but this is not possible for all ceramics like for example Si3N4. There is a lack of methods for the additive manufacturing of dense voluminous parts for most ceramics.
We have developed a new additive manufacturing technology, the Laser Induced Slip casting (LIS), based on the layerwise deposition of slurries and their local drying by laser radiation. Laser Induced Slip casting generates ceramic green bodies which can be sintered to dense ceramic components like traditional formed ceramic powder compacts. We will introduce the LIS technology, green bodies and sintered parts will be shown and their microstructure and mechanical properties will be discussed.
Most additive manufacturing processes which produce dense ceramics are nowadays limited in size because of inevitable post-processing steps like for example binder removal in stereolithography. The additive manufacturing of voluminous ceramic parts is realized by powder bed based processes which, however, generate parts with residual porosity. Via infiltration these parts can be processed to dense parts like for example SiC but this is not possible for all ceramics like for example Si3N4. There is a lack of methods for the additive manufacturing of dense voluminous parts for most ceramics.
We have developed a new additive manufacturing technology, the Laser Induced Slip casting (LIS), based on the layerwise deposition of slurries and their local drying by laser radiation. Laser Induced Slip casting generates ceramic green bodies which can be sintered to dense ceramic components like traditional formed ceramic powder compacts. We will introduce the LIS technology, green bodies and sintered parts will be shown and their microstructure and mechanical properties will be discussed.
Different imaging techniques were employed to monitor Full Notch Creep Test (FNCT) experiments addressing environmental stress cracking in more detail. The FNCT is a well-established test method to assess slow crack growth and environmental stress cracking of polymer materials, especially polyethylene. The standard test procedure, as specified in ISO 16770, provides a simple comparative measure of the resistance to crack growth of a certain material based on the overall time to failure when loaded with a well-defined mechanical stress and immersed in a liquid medium promoting crack propagation.
Destructive techniques which require a direct view on the free fracture surface, such as light microscopy and laser scanning microscopy, are compared to non-destructive techniques, i.e. scanning acoustic microscopy and xray micro computed tomography. All methods allow the determination of an effective crack length. Based on a series of FNCT specimens progressively damaged for varied Durations under standard test conditions, the estimation of crack propagation rates is also enabled. Despite systematic deviations related to the respective Imaging techniques, this nevertheless provides a valuable tool for the detailed evaluation of the FNCT and its further development.
Having been introduced almost two decades ago, Additive Manufacturing (AM) of metals has become industrially viable for a large variety of applications, including aerospace, automotive and medicine. Powder bed techniques such as Selective Laser Melting (SLM) based on layer-by-layer deposition and laser melt enable numerous degrees of freedom for the geometrical design. Developing during the manufacturing process, residual stresses may limit the application of SLM parts by reducing the load bearing capacity as well as induce unwanted distortion depending on the boundary conditions specified in manufacturing.
The residual stress distribution in IN718 elongated prisms produced by SLM was studied non-destructively by means of neutron (bulk) and laboratory X-ray (surface) diffraction. The samples with different scanning strategies, i.e. hatching length, were measured in as-build condition (on a build plate) and after removal from the build plate.
The absolute values of all stress components decreased after removal from the build plate. Together with surface scan utilizing a coordinate-measuring machine (CMM), it is possible to link the stress release to the sample distortion. Obtained results indicated different residual stress states for each of the transversal, longitudinal and normal component depending on the thermal gradient in the respective direction.
Having been introduced almost two decades ago, Additive Manufacturing (AM) of metals has become industrially viable for a large variety of applications, including aerospace, automotive and medicine. Powder bed techniques such as Selective Laser Melting (SLM) based on layer-by-layer deposition and laser melt enable numerous degrees of freedom for the geometrical design. Developing during the manufacturing process, residual stresses may limit the application of SLM parts by reducing the load bearing capacity as well as induce unwanted distortion depending on the boundary conditions specified in manufacturing.
The residual stress distribution in IN718 elongated prisms produced by SLM was studied non-destructively by means of neutron (bulk) and laboratory X-ray (surface) diffraction. The samples with different scanning strategies, i.e. hatching length, were measured in as-build condition (on a build plate) and after removal from the build plate.
The absolute values of all stress components decreased after removal from the build plate. Together with surface scan utilizing a coordinate-measuring machine (CMM), it is possible to link the stress release to the sample distortion. Obtained results indicated different residual stress states for each of the transversal, longitudinal and normal component depending on the thermal gradient in the respective direction.
Wollastonite (CaSiO 3 ) – diopside (CaMgSi 2 O 6 ) glass-ceramic scaffolds have been successfully fabricated using two different additive manufacturing techniques: powder-based 3D printing (3DP) and digital light processing (DLP), coupled with the sinter-crystallization of glass powders with two different compositions. The adopted manufacturing process depended on the balance between viscous flow sintering and crystallization of the glass particles, in turn in fluenced by the powder size and the sensitivity of CaO – MgO – SiO 2 glasses to surface nucleation. 3DP used coarser glass powders and was more appropriate for low temperature firing (800 – 900 °C), leading to samples with limited crystallization. On the contrary, DLP used finer glass powders, leading to highly crystallized glass-ceramic samples. Despite the differences in manufacturing technology and crystallization, all samples featured very good strength-to-density ratios, which bene fit theiruse for bone tissue engineering applications. The bioactivity of 3D-printed glass-ceramics after immersion in simulated body fluid and the similarities, in terms of ionic releases and hydroxyapatite formation with already validated bioactive glass-ceramics, were preliminarily assessed.
Tricalcium phosphate (b-TCP) can be used as bone graft, exhibiting suitable bioabsorption and osteoconduction properties. The presence of silica may induce the formation of a hydroxyapatite layer, enhancing the integration between implant and bone tissue. Preceramic polymers present silicon in their composition, being a source of SiO2 after thermal treatment. Using the versatility of 3D printing, b-TCP and a polysiloxane were combined to manufacture a bulkb-TCP with a silica coating. For the additive manufacturing process, PMMA powder was used as passive binder for the b-TCP particles, and polymethylsilsesquioxane (MK), dissolved in an organic solvent, was used both as a printing binder (ink) and as the source of SiO2 for the coating. Five distinct coating compositions were printed with increasing amounts of MK. The structures were then submitted to heat treatment at 1180 °C for 4 h. XRD and FTIR showed no chemical reaction between the calcium phosphate and silica. SEM allowed observation of a silicon-based ating on the structure surface. Mechanical strength of the sintered porous structures was within the range of that of trabecular bones.
A shape evolution approach based on the thermally activated self-organization of 3D printed parts into minimal surface area structures is presented. With this strategy, the present communication opposes currently established additive manufacturing strategies aiming to stipulate each individual volumetric element (voxel) of a part. Instead, a 3D structure is roughly defined in a 3D printing process, with all its advantages, and an externally triggered self-organization allows the formation of structural elements with a definition greatly exceeding the volumetric resolution of the printing process. For enabling the self-organization of printed objects by viscous flow of material, functionally graded structures are printed as rigid frame and melting filler. This approach uniquely combines the freedom in design, provided by 3D printing, with the mathematical formulation of minimal surface structures and the knowledge of the physical potentials governing self-organization, to overcome the paradigm which strictly orrelates the geometrical definition of 3D printed parts to the volumetric resolution of the printing process. Moreover, a transient liquid phase allows local programming of functionalities, such as the alignment of functional particles, by means of electric or magnetic fields.
The Layerwise Slurry Deposition is a technology for the deposition of highly packed powder layers. A powder bed is achieved by depositing and drying layers of a ceramic suspension by means of a doctor blade. This deposition technique was combined with the binder jetting technology to develop a novel Additive Manufacturing technology, named LSD-print. The LSD-print was applied to a porcelain ceramic. It is shown that it was possible to produce parts with high definition, good surface finish and at the same time having physical and mechanical properties close to those of traditionally processed porcelain, e.g. by slip casting.
This technology shows high future potential for being integrated alongside traditional production of porce-lain, as it is easily scalable to large areas while maintaining a good definition. Both the Layerwise Slurry Deposition method and the binder jetting technologies are readily scalable to areas as large as > 1 m2.
The presence of water in the surrounding atmosphere of a propagating crack has a major influence on the subcritical crack growth. While these external phenomena are well understood, there is still a lack of knowledge on the influence of structurally bound water on crack propagation. Thus, our recent study aims on the analysis of crack propagation in water bearing soda-lime silicate glasses with up to 8 wt.% water. The samples were synthesized in an internally heated pressure vessel at 0.5 GPa. Since this preparation route limits the sample sizes, standard test geometries allowing for the determination of stress intensity factors, such as double cantilever beam, are not feasible. Thus, radial cracks in the hydrous glasses were initiated by Vickers indentation and crack growth was simultaneously captured with a camera system. An automated image analysis algorithm was used for the analysis of the crack length of each single video frame. To minimize influences by atmospheric water, all experiments were conducted in a glovebox purged with dry N2. About 150 cracks per glass composition were analyzed to provide statistical significance of the Vickers-induced SCCG. The results show that structurally bound water has a major influence on SCCG by means of crack lengths, growth rates and time of crack initiation.
Statistical analysis of Vickers induced subcritical crack growth in soda-lime silicate glasses
(2018)
Studies on Vickers induced subcritical crack growth are controversially discussed since the stresses that drive the crack growth are distributed three dimensionally within the material and cannot be retraced by available methods. Hence, empirical approaches are used to calculate mechanical material parameters such as the stress intensity factor KI. However, the results of these approaches show large deviations from those measured by standardized techniques such as double cantilever beam (DCB) or double cleavage drilled compression (DCDC). Yet, small specimen sizes and low specimen quantities can prevent the execution of DCB and DCDC measurements. Here we present an approach that is based on a statistical analysis of Vickers induced radial cracks. For this purpose more than 150 single radial cracks were analyzed. The cracks were generated in a commercial soda-lime silicate glass. The experiments were performed in a glovebox purged with dry nitrogen gas to minimize the influence of atmospheric water on crack growth. The temporally resolved evolution of the radial cracks was monitored in-situ using an inverted microscope equipped with a camera system directly below the Vickers indenter. An automated image analysis software was used to determine the crack length over time. The data show that the crack propagation and thereby the crack velocities are not uniformly but statistically distributed. These findings allow, using the statistical mean value of the distributions in combination with DCB data, a precise formulation of KI for each measured crack length.
Premature failure of glass under load is caused by sub-critical crack growth (SCCG) originate from microscopic flaws at the surface. While SCCG is related to the humidity of the ambient atmosphere, leading to stress corrosion phenomena at the crack tip, the detailed mechanism and the effect of different network formers are still not fully understood. For more clarity, various soda silicate glasses with a second network former were investigated by double cantilever beam technique: Na2O*Al2O3*SiO2 (NAS), Na2O*B2O3*SiO2 (NBS), Na2O*PbO*SiO2 (NPbS).
Three effects on the crack growth velocity, v, versus stress intensity, KI, curves were found out. The slope in region I, which is limited by corrosion, increases in the order NAS < NBS ≲ NPbS. The velocity range of region II reflecting the transition between corrosion effected and inert crack growth (region III), varies within one order of magnitude between the glasses. The KI region of inert crack growth strongly scatters between 0.4 and 0.9 MPam1/2. For comparison, crack growth at different humidity in commercial soda lime silicate glass (NCS) was measured.
Die Festigkeit von Gläsern wird durch die Oberflächenqualität beeinflusst. Kommt es neben dem Auftreten von Defekten zusätzlich zum Risswachstum ausgehend hiervon, wird die Festigkeit minimiert. Das Wachstum hängt dabei maßgeblich von der Luftfeuchtigkeit ab. Dieses Ermüdungsverhalten von Gläsern besser zu verstehen und dabei die Mechanismen und den Einfluss von im Volumen eingebauten Wasser auf das unterkritische Risswachstum zu untersuchen, ist Ziel der Arbeiten. Als Teilprojekt im Rahmen des DFG Schwerpunktprogramms SPP 1594 „Ultrastrong glasses“ soll der Einfluss des im Volumen eingebauten Wassers auf die Rissspitze untersucht werden. Zusammen mit der Leibniz Universität Hannover und der TU Clausthal werden hierfür hochwasserhaltige Gläser (bis zu 8 Gew%) bei 8 kbar über die Flüssigphase synthetisiert, die makroskopisch den hohen Wasseranteil nachstellen. Die Charakterisierung erfolgt hinsichtlich des Wassereinbaus, der mechanischen Eigenschaften und des Risswachstums. Die Arbeiten in Berlin beziehen sich hierbei auf die Messungen des unterkritischen Risswachstums in Luft und Vakuum, sowie Verlustwinkelmessungen.
Erste Ergebnisse zeigen Unterschiede im korrosionsbeeinflussten (langsames) und inerten (schnelles und im Vakuum stattfindendes) Risswachstumsverhalten der untersuchten Gläsern. Die Rissgeschwindigkeit beim Übergang vom korrosionsbeeinflussten zum inerten Risswachstum ist hin¬gegen für alle Gläser ähnlich und folglich ein kinetisch durch den äußeren Wassertransport an die Rissspitze bestimmter Prozess. Der Widerstand gegen Risswachstum steigt mit Tg und zusätzlich kann anhand der Verlustwinkelmessungen ein Zusammenhang zwischen der Netzwerk- und der β-Relaxation ermittelt werden. Je höher der Wassergehalt im Glas ist, desto niedriger wird Tg und einfacher das Risswachstum, welches sich durch längere Risse kennzeichnet. Besonders stark tritt dieser Effekt bei einem Überschuss an molekularem Wasser auf.
The durability of concrete structures and its performance over the lifetime is strongly influenced by many interacting phenomena such as e.g. mechanical degradation due to fatigue loading, loss of prestress, degradation due to chemical reactions or creep and shrinkage. Failure due to cyclic loading is generally not instantaneous, but characterized by a steady damage accumulation.
Many constitutive models for concrete are currently available, which are applicable for specific loading regimes, different time scales and different resolution scales. A key limitation is that the models often do not address issues related to fatigue on a structural level. Very few models can be found in the literature that reproduce deterioration of concrete under repeated loading-unloading cycles.
The objective of this paper is the presentation of numerical methods for the simulation of concrete under fatigue loading using a temporal multiscale method.
First, a continuum damage model for concrete is developed with a focus on fatigue under compressive stresses. This includes the possibility to model stress redistributions and capture size effects. In contrast to cycle based approaches, where damage is accumulated based on the number of full stress cycles, a strain based approach is developed that can capture cyclic degradation under variable loading cycles including different amplitudes and loading frequencies. Second, a multiscale approach in time is presented to enable structural computations of fatigue failure with a reduced computational effort. The damage rate within the short time scale corresponding to a single cycle is computed based on a Fourier based approach. This evolution equation is then solved on the long time scale using different time integration schemes.
Dissolved water decisively influences numerous thermally activated relaxation phenomena in glasses like stress relaxation, sub-critical crack growth, internal friction, viscosity, sintering, and crystallization. Thermoanalytical methods can essentially help for better understanding of these phenomena. The lecture introduces the Vacuum Hot Extraction method (VHE) and illustrates its possibilities for measuring water content, degassing and mobility. As another thermoanalytical method, the Dynamic Mechanical Themoanalysis (DMA), allowing to study the effect of dissolved water on the internal friction in glasses, is introduced.
Glass powders are promising candidates for manufacturing a broad diversity of sintered materials like sintered glass-ceramics, glass matrix composites or glass bonded ceramics with tailored mechanical, thermal, electrical and optical properties and complex shape. Its wide and precise adjustability makes this class of materials a key component for advanced technologies. Processing of glass or composite powders often allow even more flexibility in materials design. At the same time, however, processing can have substantial effects on the glass powder surface and sinterability. Thus, mechanical damage and surface contamination can strongly enhance surface crystallization, which may retard or even fully prevent densification. Whereas sintering and concurrent crystallization have been widely studied, partially as cooperative effort of the TC7 of the ICG, and although glass powder sintering is predominantly applied for glasses of low crystallization tendency, sintering is also limited by gas bubble formation or foaming. The latter phenomenon is much less understood and can occur even for slow crystallizing glass powders. The lecture illustrates possible consequences of glass powder processing on glass sintering, crystallization and foaming.
Wasser in Silicatglas
(2018)
Giant magneto-resistive (GMR) sensor based metal magnetic memory (MMM) technique is proposed for mapping of deformation-induced self-magnetic leakage fields (SMLFs) in carbon steel. The specimens were subjected to different amounts of tensile deformation and the deformation-induced SMLFs were measured using a GMR sensor after unloading the specimens. 3D-nonlinear finite element modeling was performed to predict stress–strain state in a steel specimen under tensile load. The experimentally obtained SMLF images were correlated with the finite element model predicted stress–strain states. Studies reveal that the MMM technique can detect the plastic deformation with signal-to-noise ratio better than 20 dB. The technique enables the mapping of plastic deformation in carbon steels for the evaluation of the severity of deformation. The study also reveals that deformation-induced SMLF is influenced by the presence of initial surface residual stress, introduced by shot peening. The intensity of SMLF signal is found to increase with increase in tensile load and decrease with shot peening.
Der Vortrag gibt eine Einführung in die Methode der Vakuumheißextraktion und beschreibt die Anwendungsmöglichkeiten der an der BAMN betriebenen Anlage.
Shear testing can contribute to a better understanding of the plastic deformation of Ni-base superalloy single crystals. In the present study, shear testing is discussed with special emphasis placed on its strengths and weaknesses. Key mechanical and microstructural results which were obtained for the high-temperature (T ≈ 1000 °C) and low-stress (τ ≈ 200 MPa) creep regime are briefly reviewed. New 3D stereo STEM images of dislocation substructures which form during shear creep deformation in this regime are presented. It is then shown which new aspects need to be considered when performing double shear creep testing at lower temperatures (T < 800 °C) and higher stresses (τ > 600 MPa). In this creep regime, the macroscopic crystallographic [11−2](111) shear system deforms significantly faster than the [01−1](111) system. This represents direct mechanical evidence for a new planar fault nucleation scenario, which was recently suggested (Wu et al. in Acta Mater 144:642–655, 2018). The double shear creep specimen geometry inspired a micro-mechanical in-situ shear test specimen. Moreover, the in-situ SEM shear specimen can be FIB micro-machined from prior dendritic and interdendritic regions. Dendritic regions, which have a lower γ′ volume fraction, show a lower critical resolved shear stress.
The creep behavior of single crystals of the nickel-based superalloy CMSX-4 was investigated at 1288 °C, which is the temperature of the hot isostatic pressing treatment applied to this superalloy in the industry. It was found that at this super-solvus temperature, where no gammaPrime-strengthening occurs, the superalloy is very soft and rapidly deforms under stresses between 4 and 16 MPa. The creep resistance was found to be very anisotropic, e.g., the creep rate of [001] crystals was about 11 times higher than that of a [111] crystal. The specimens of different orientations also showed a very different necking behavior. The reduction of the cross-sectional area psi of [001] crystals reached nearly 100 pct, while for a [111] crystal psi = 62 pct. The EBSD analysis of deformed specimens showed that despite such a large local strain the [001] crystals did not recrystallize, while a less deformed [111] crystal totally recrystallized within the necking zone. The recrystallization degree was found to be correlated with deformation behavior as well as with dwell time at high temperature. From the analysis of the obtained results (creep anisotropy, stress dependence of the creep rate, traces of shear deformation, and TEM observations), it was concluded that the main strain contribution resulted from <01-1>{111} octahedral slip.
The Ni-Cr-Mo-W alloy is characterized by the excellent high-temperature corrosion resistance, good strength and ability to work in aggressive environments. To protect the surface of the substrate 13CrMo4-5 steel against aggressive environments the Inconel 686 as clad layer was used. The corrosion process was performed in oxidizing mixture of gases like O2, COx, SOx. The second part of corrosion Experiment concerned the corrosion test of the coating in reducing atmosphere of the specified gases with ashes, which contained e.g. Na, Cl, Ca, Si, C, Fe, Al.
Borosilicate glasses (16Na2O–10B2O3–74SiO2, NBS) with water contents up to 22 mol% H2O were prepared to study the effect of water on structural relaxation using DTA, viscometry and internal friction measurements. The results show that the glass transition temperature Tg of DTA and the isokom temperature T12, of viscometry are in excellent agreement, confirming the equivalence of enthalpy and viscous relaxation for NBS glass. Combining Tg data with water speciation data demonstrates that OH groups are mainly responsible for the decrease of Tg with increasing hydration, while molecular water plays only a minor role. Internal friction spectra at 7.125 Hz confirm the decisive influence of water on mechanical relaxation. The temperature range of α-relaxation (glass transition) strongly decreases while two β-relaxation peaks (sub-Tg) progressively appear with increasing water content. A high temperature β-relaxation peak, attributed to the presence of OH groups, shifts from 670 to 450 K as total water content increases from 0.01 to 5 wt%. A low temperature β-relaxation peak, attributed to molecular water, appears at 380 K and 330 K in glasses containing 3 and 5 wt% H2O, respectively. These findings suggest that relaxation mechanism of different hydrous species at low temperature may contribute to fatigue of stressed glasses.
Up to now, the mechanisms of surface nucleation and surface-induced texture formation are far from being understood. Corresponding phenomena are discussed hypothetically or even controversial, and related studies are restricted to very few glasses. In this talk the state of the art on mechanisms of surface nucleation are summarized. On one hand, mechanical damaged surfaces show high nucleation activity, at which the nucleation occurs at convex tips and edges preferentially. On the other hand, solid foreign particles are dominant nucleation sites at low damaged surfaces. They enable nucleation at temperatures even far above Tg. The nucleation activity of the particles is substantially controlled by their thermal and chemical durability. But no systematic studies on initially oriented crystal growth or nucleation from defined active nucleation sites have been pursued, so far. Therefore, the main objective of a just started project is to advance the basic understanding of the mechanisms of surface-induced microstructure formation in glass ceramics. We shall answer the question whether preferred orientation of surface crystals is the result of oriented nucleation or caused by other orientation selection mechanisms acting during early crystal growth. In both cases, crystal orientation may be caused by the orientation of the glass surface itself or the anisotropy and orientation of active surface nucleation defects. As a first attempt we focused on possible reorientation of separately growing surface crystals during early crystal growth. First results show clear evidence that separately growing crystals can reorient themselves as they are going to impinge each other.
Sintered bioactive glass scaffolds of defined shape and porosity, e.g. made via additive manufacturing, must provide sufficient bioactivity and sinterability. As higher bioactivity is often linked to high corrosion and crystallization tendency, a certain compromise between sintering ability and bioactivity is therefore required. Groh et al. developed a fluoride-containing bioactive glass (F3), which allows fiber drawing and shows a bioactivity well comparable to that of Bioglass®45S5.
To study whether and to what extent the sinterability of F3 glass powder is controlled by particle size, coarse and fine F3 glass powders (300-310µm and 0-32µm) were prepared by crushing, sieving and milling. Sintering, degassing and phase transformation during heating were studied with heating microscopy, vacuum hot extraction (VHE), DTA, XRD, and SEM.
For the coarse glass powder, sintering proceeds slowly and is limited by surface crystallization of primary Na2CaSi2O6 crystals. Although the crystallization onset of Na2CaSi2O6 is shifted to lower temperature, full densification is attained for the fine powder. This finding indicate that certain porosity might be tuned via particle size variation. Above 900°C, intensive foaming is evident for the fine powder. VHE studies revealed that carbon species are the main foaming source.
Thermoelectric materials can convert waste heat directly into electrical power by using the Seebeck effect. Calcium cobaltite Ca3Co4O9 is a promising p-type oxide thermoelectric material for applications between 600 °C and 900 °C in air. The properties and morphology of Ca3Co4O9 are strongly anisotropic because of its crystal structure of alternating layers of CoO2 and Ca2CoO3. By aligning the plate-like grains, the anisotropic properties can be assigned to the component. Pressure-assisted sintering (PAS), as known from large-scale production of low temperature co-fired ceramics, was used to sinter multilayers of Ca3Co4O9 green tape at 900 °C with different pressures and dwell times. In-situ shrinkage measurements, microstructural investigations and electric measurements were performed. Pressure-less sintered multilayers have a 2.5 times higher electrical conductivity at room temperature than dry pressed test bars with randomly oriented particles. The combination of tape casting and PAS induces a pronounced alignment of the anisotropic grains. Relative density increases from 57 % after free sintering for 24 h to 94 % after 2 h of PAS with 10 MPa axial load. By applying a uniaxial pressure of 10 MPa during sintering, the electrical conductivity (at 25°C) improves by a factor of 15 compared to test bars with randomly oriented particles. The high temperature thermoelectric properties show the same dependencies. The smaller the applied axial load, the lower the relative densities, and the lower the electrical conductivity. Longer dwell times may increase the density and the electrical conductivity significantly if the microstructure is less densified as in the case of a small axial load like 2 MPa. At higher applied pressures the dwell time has no significant influence on the thermoelectric properties. This study shows that PAS is a proper technique to produce dense Ca3Co4O9 panels with good thermoelectric properties similar to hot-pressed tablets, even in large-scale production.
3D structural investigations are described by X-ray laminography studies of sandwich shell segments, made of a PVC foam core, covered by non-crimp fabric glass fibre composite lay-ups processed by vacuum assisted resin infusion of epoxy. The specific scope of this study is to image transversal flaws within the foam core (joints) and of single ply overlaps. Test flaws were purposely implemented in order to simulate typical failure under cyclic load. In a dedicated test rig for shell structures, the flaw evolution/propagation is monitored by thermography and optical 3D inspection of deformation. Due to the unfavourable preconditions for classical computed tomography as of large aspect ratio, the samples were investigated by coplanar translational laminography. Its limited range of observation angles of ± 45°, results in anisotropic artefacts about the normal to the sample surface, but the typical flaws are well visualized in the as-prepared state, in a state of early damage, and in the repaired state.
The longitudinal and transverse strength of three unidirectional thermoplastic prepreg systems: carbon fiber/polypropylene (CF/PP), polyamide 6 (CF/PA6), and polyphenylene sulfide (CF/PPS) are studied and analytical formulas are proposed for the estimation of matrix and fiber/matrix interface properties from composites properties. Since the matrices are semi-crystalline thermoplastics, the influence of cooling rate on the strength is statistically evaluated. While the 0° tensile strength is found to be independent of the cooling rate, the 90° tensile strength is strongly influenced by the matrix type and cooling rate. The matrix modulus increases as the cooling rate is decreased; the degree of crystallinity also increases. The matrix residual stress, interfacial shear strength, and mode II interlaminar fracture toughness are also found to depend on the cooling rate, with the trends different for different matrices.
The increasing pollution of terrestrial and aquatic ecosystems with plastic debris leads to the accumulation of microscopic plastic particles of still unknown amount. To monitor the degree of contamination analytical methods are urgently needed, which help to quantify microplastics (MP). Currently, time-costly purified materials enriched on filters are investigated both by micro-infrared spectroscopy and/or micro-Raman. Although yielding precise results, these techniques are time consuming, and are restricted to the analysis of a small part of the sample in the order of few micrograms. To overcome these problems, here we tested a macroscopic dimensioned NIR process-spectroscopic method in combination with chemometrics. For calibration, artificial MP/soil mixtures containing defined ratios of polyethylene, polyethylene terephthalate, polypropylene, and polystyrene with diameters < 125 µm were prepared and measured by a process FT-NIR spectrometer equipped with a fiber optic reflection probe. The resulting spectra were processed by chemometric models including support vector machine regression (SVR), and partial least squares discriminant analysis (PLS-DA). Validation of models by MP mixtures, MP-free soils and real-world samples, e.g. and fermenter residue, suggest a reliable detection and a possible classification of MP at levels above 0.5 to 1.0 mass% depending on the polymer. The benefit of the combined NIRS chemometric approach lies in the rapid assessment whether soil contains MP, without any chemical pre-treatment. The method can be used with larger sample volumes and even allows for an online prediction and thus meets the demand of a high-throughput method.
The alloying system Co-Al-W-Ta is comprehensively investigated in the vicinity of the compositional point Co-9Al-10W-2Ta, at. pct. These investigations provided a large amount of quantitative information, which can be used for alloy development, namely, the compositional dependences of the The alloying system Co-Al-W-Ta is comprehensively investigated in the vicinity of the compositional point Co-9Al-10W-2Ta, at. pct. These investigations provided a large amount of quantitative information, which can be used for alloy development, namely, the compositional dependences of the γ‘-solvus, solidus, and liquidus temperatures; fraction of the extrinsic phases after casting; the compositional dependence of the γ/γ‘-lattice misfit; the element partitioning between γ- and γ‘-phases; and the two Phase compositional area γ/γ‘ in the Co-rich part of the Co-Al-W-Ta phase diagram at 900°C. It is shown that additions of Ta elevate the γ‘-solvus temperature and increase the γ/γ‘-lattice misfit, but adding more than about 3 at. pct Ta results in a large amount of undissolvable extrinsic phases. Additionally, two Co-Al-W-Ta alloys with lower content of W were developed and solidified as [001] single crystals for mechanical testing in a temperature range between 20 and 1200°C. These tests included measurement of the Young modulus, tensile tests with constant strain rate, and stress rupture tests. It was found that at temperatures up to about 750°C the ultimate tensile strength of Co-Al-Ta-W alloys can be at the same level or even higher than of Ni-based superalloys.
3D structural investigations are described by X-ray laminography studies of sandwich shell segments, made of a PVC foam core, covered by non-crimp fabric glass fibre composite lay-ups processed by vacuum assisted resin infusion of epoxy. The specific scope of this study is to image transversal flaws within the foam core (joints) and of single ply overlaps. Test flaws were purposely implemented in order to simulate typical failure under cyclic load. In a dedicated test rig for shell structures, the flaw evolution/propagation is monitored by thermography and optical 3D inspection of deformation. Due to the unfavourable preconditions for classical computed tomography as of large aspect ratio, the samples were investigated by coplanar translational laminography. Its limited range of observation angles of ± 45°, results in anisotropic artefacts about the normal to the sample surface, but the typical flaws are well visualized in the as-prepared state, in a state of early damage, and in the repaired state.
We investigated the effect of water vapor in the initial stages of SO2 corrosion of an Fe-9Cr-0.5Mn model alloy at 650 °C. Two separate experiments were run, one with 99.5%-Ar + 0.5%-SO2 and one with 69.5%-Ar + 0.5%-SO2 with 30%-H2O atmosphere. During the experiment the scale growth was observed in-situ, using energy dispersive X-ray diffraction (EDXRD). Our results confirm an increased speed of oxygen transport into the material, with the addition of water, while the transport of sulfur appears to be less affected.
Cyclic fatigue behavior of glass fiber reinforced epoxy resin at ambient and elevated temperatures
(2018)
The fatigue behavior of ±45° glass fiber reinforced epoxy resin under cyclic mechanical and constant thermal loading is investigated in this study. Tests at three different temperature levels in the range 296 K to 343 K have been performed in order to create S-N curves for each temperature level. The specimen damage is measured in-situ using optical grayscale analysis. The characteristic damage state (CDS) is evaluated for each specimen. It is shown that the point of CDS is suitable as a failure criterion to compare the resulting S-N curves. With micromechanical formulations, the temperature-dependent matrix effort is calculated for each stress-temperature level. In terms of matrix effort, the longest fatigue life is reached at high temperatures, while, in terms of stress, the lowest fatigue life is reached at the highest temperatures.
Additive Manufacturing (AM) of metals has become industrially viable for a large variety of applications, including aerospace, automotive and medicine. Powder bed techniques such as Selective Laser Melting (SLM) based on layer-by-layer deposition and laser melt enable numerous degrees of freedom for the geometrical design. Developing during the manufacturing process, residual stresses may limit the application of SLM parts by reducing the load bearing capacity as well as induce unwanted distortion depending on the boundary conditions specified in manufacturing.
The residual stress distribution in the bulk of IN718 elongated prisms produced by SLM was studied non-destructively by means of neutron diffraction. The samples with different scanning strategies, i.e. hatching length, were measured in as-build condition (on a build plate) and after removal from the build plate.
The absolute values of all stress components decreased after removal from the build plate. Together with surface scan utilizing a coordinate-measuring machine (CMM), it is possible to link the stress release to the sample distortion. Obtained results indicated different residual stress states for each of the transversal, longitudinal and normal component depending on the thermal gradient in the respective direction.
Cyclic fatigue behavior of glass fiber reinforced epoxy resin at ambient and elevated temperatures
(2018)
The fatigue behavior of ±45° glass fiber reinforced epoxy resin under cyclic mechanical and constant thermal loading is investigated in this study. Tests at three different temperature levels in the range 296 K to 343 K have been performed in order to create S-N curves for each temperature level. The specimen damage is measured in-situ using optical grayscale analysis. The characteristic damage state (CDS) is evaluated for each specimen. It is shown that the point of CDS is suitable as a failure criterion to compare the resulting S-N curves. With micromechanical formulations, the temperature-dependent matrix effort is calculated for each stress-temperature level. In terms of matrix effort, the longest fatigue life is reached at high temperatures, while, in terms of stress, the lowest fatigue life is reached at the highest temperatures.
Um den sicheren Betrieb von Windkraftanlagen zu gewährleisten, werden Rotorblätter nach der Fertigung und nach Reparatur mit verschiedenen zerstörungsfreien Verfahren auf Schaden untersucht. Bei der Fertigung von Blattschalen, die in einer Sandwich-Schalenbauweise gefertigt werden, entstehen Imperfektionen, die unter Belastung zu großen Rissen führen können. Zur Prüfung von Blattschalen wird unter anderem Ultraschallprüfung in Kontakttechnik eingesetzt. Um den Wartungsaufwand von Ultraschallanlagen zu reduzieren und um manche Kompositstrukturen vor Koppelmittel zu schützen, wird die Anwendung von Luftultraschall erforscht. Insbesondere große Fortschritte gibt es im Bereich der Entwicklung neuer Wandler.
In diesem Beitrag berichten wir über die Luftultraschallprüfung von Schalen für Rotorblätter. Es wurden typische Sandwichschalenstrukturen hergestellt und mit einem eigenentwickelten Schalenprüfstand unter simulierter Betriebsbeanspruchung belastet. Die in den Schalenprüfkörpern entstandenen Schäden wurden außerhalb des Prüfstandes mit Luftultraschall in Durchschallung untersucht. Es wurden fokussierende Wandler auf Basis von Ferroelektreten entwickelt und für diese Prüfungen eingesetzt. Mit zusätzlicher elektrischer Vorspannung konnte die Empfindlichkeit der Empfänger deutlich erhöht werden. Die nach dem Lastwechsel entstandenen Schäden in den Rotorblattschalen waren eindeutig zu detektieren.
Um den sicheren Betrieb von Windkraftanlagen zu gewährleisten, werden Rotorblätter nach der Fertigung und nach Reparatur mit verschiedenen zerstörungsfreien Verfahren auf Schaden untersucht. Bei der Fertigung von Blattschalen, die in einer Sandwich-Schalenbauweise gefertigt werden, entstehen Imperfektionen, die unter Belastung zu großen Rissen führen können. Zur Prüfung von Blattschalen wird unter anderem Ultraschallprüfung in Kontakttechnik eingesetzt. Um den Wartungsaufwand von Ultraschallanlagen zu reduzieren und um manche Kompositstrukturen vor Koppelmittel zu schützen, wird die Anwendung von Luftultraschall erforscht. Insbesondere große Fortschritte gibt es im Bereich der Entwicklung neuer Wandler.
In diesem Beitrag berichten wir über die Luftultraschallprüfung von Schalen für Rotorblätter. Es wurden typische Sandwichschalenstrukturen hergestellt und mit einem eigenentwickelten Schalenprüfstand unter simulierter Betriebsbeanspruchung belastet. Die in den Schalenprüfkörpern entstandenen Schäden wurden außerhalb des Prüfstandes mit Luftultraschall in Durchschallung untersucht. Es wurden fokussierende Wandler auf Basis von Ferroelektreten entwickelt und für diese Prüfungen eingesetzt. Mit zusätzlicher elektrischer Vorspannung konnte die Empfindlichkeit der Empfänger deutlich erhöht werden. Die nach dem Lastwechsel entstandenen Schäden in den Rotorblattschalen waren eindeutig zu detektieren.
Thermoelektrische Materialien können durch die Nutzung des Seebeckeffektes einen Temperaturunterschied direkt in eine Spannung umwandeln. Calciumcobaltit (p-typ) und Calciummanagant (n-typ) sind 2 der vielversprechendsten oxidischen thermoelektrischen Materialien. Für die Entwicklung von kostengünstigen Multilayergeneratoren ist das Co-sintern dieser beiden Materialien notwendig und deshalb eine Anpassung der Sintertemperatur nötig. Calciummangant wird herkömmlicherweise zwischen 1200°C und 1350°C gesintert. Calciumcobaltit erfährt einen ungewünschte Phasenumwandlung bei 926°C, es kann allerding bei 900°C unter 7.5MPa zu 95% dicht gesintert werden. Demzufolge, ist eine Co-sintertemperatur von 900°C anzustreben. Aus diesem Grund wurden mehrere Strategien zur Absenkung der Sintertemperatur von Calciummanaganat untersucht. Zum einen die Zugabe niedrigschmelzender Additive, zum anderen die Zugabe von Additiven, die eine eutektische Schmelze bilden. Es konnte gezeigt werden, dass für Calciummanganat die Verwendung von eutektischen Schmelzen besser geeignet ist als die Verwendung von niedrigschmelzenden Additiven um die Sintertemperatur zu senken.“
Technically relevant P92 steel (9% Cr) was coated with a micron-thick porous alumina layer prepared by sol-gel technique and treated with flue gas (60 CO2-30 H2O-2 O2-1 SO2-7 N2 (mole fraction in %)) at 650 ° to mimic an oxyfuelcombustion process. Local defects in the coating were marked using focused ion beam (FIB) technique and were inspected after exposition to hot flue gas atmosphere at 300, 800, and 1300 h, respectively. Local defects like agglomerated alumina sol particles tend to spall off from the coating uncovering the underlying dense chromia scale. Re-coating was found to restore the protection ability from oxidation when repeatedly treated with hot flue gas. Cracks and voids did not promote the local oxidation due to the formation of crystalline Mn/S/O species within and on top of the coating. The protective character of the steel-coating system is a result of (i) the fast formation of a dense chromia scale at the surface of sol-gel alumina-coated P92 steel bars in combination with (ii) the porous alumina coating acting as diffusion barrier, but also as diffusion partner in addition with (iii) fast Mn outward diffusion capturing the S species from flue gas.
Die Bundesanstalt für Materialforschung und -prüfung (BAM) ist eine Ressortforschungseinrichtung, die zum Schutz von Mensch, Umwelt und Sachgüter, forscht, prüft und berät. Im Fokus aller Tätigkeiten in der Materialwissenschaft, der Werkstofftechnik und der Chemie steht dabei die technische Sicherheit von Produkten und Prozessen. Dazu werden Substanzen, Werkstoffe, Bauteile, Komponenten und Anlagen sowie natürliche und technische Systeme erforscht und auf sicheren Umgang oder Betrieb geprüft und bewertet. Schwerpunkt des Vortrages sind multimodale Polymeranalytik, nanoskalige Sensormaterialien und die Charakterisierung von technischen Eigenschaften von Polymeren sowie ihre Alterung und Umweltrelevanz.
Due to the increasing global demand for pure silver, native wire silver aggregates in very high purities are gaining more industrial attention. Up to the present, no substantial metallurgical Investigation of natural wire silver exists in the accessible literature. To convey urgently needed cross-disciplinary fundamental knowledge for geoscientists and metallurgical engineers, twenty natural wire silver specimens from eight different ore deposits have been investigated in detail for the first time by EBSD (Electron Back Scattering Diffraction), supported by light microscopy and micro-probe analyses. The improved understanding of the natural silver wire microstructure provides additional Information regarding the growth of natural silver aggregates in comparison to undesired artificial growth on electronic devices. Clear evidence is provided that natural silver curls and hairs exhibit a polycrystalline face-centered cubic microstructure associated with significant twinning. Although the investigated natural wire silver samples have relatively high purity (Ag > 99.7 wt.-%), they contain a variety of trace elements such as, S, Cu, Mn, Ni, Zn, Co and Bi, As and Sb. Additionally, Vickers micro-hardness measurements are provided for the first time which revealed that natural silver wires and curls are softer than it might be expected from conversion of the general Mohs hardness of 2.7.
Tooth wear induced by abrasive particles is a key process affecting dental function and life expectancy in mammals. Abrasive particles may be plant endogenous opal phytoliths, exogene wind-blown quartz dust or rain borne mineral particles ingested by mammals. Nano-indentation hardness of abrasive particles and dental tissues is a significant yet not fully established parameter of this tribological system. We provide consistent nano-indentation hardness data for some of the major antagonists in the dental tribosystem (tooth enamel, tooth dentine and opaline phytoliths from silica controlled cultivation). All indentation data were gathered from native tissues under stable and controlled conditions and thus maximize comparability to natural systems. Here we show that native (hydrated) wild boar enamel exceeds any hardness measures known for dry herbivore tooth enamel by at least 3 GPa. The native tooth enamel is not necessarily softer then environmental quartz grit, although there is little overlap. The native hardness of the tooth enamel exceeds that of any silica phytolith hardness recently published. Further, we find that native reed phytoliths equal native suine dentine in hardness, but does not exceed native suine enamel. We also find that native suine enamel is significantly harder than dry enamel and dry phytoliths are harder than native phytoliths. Our data challenge the claim that the culprit of tooth wear may be the food we chew, but suggest instead that wear may relates more to exogenous than endogenous abrasives.
In the present study, microstructure and texture development during single and multiple pass friction stir processing (FSP) of a strain hardenable wrought AlMg alloy (AA5086) was investigated. Subtle differences were observed while comparing with heat treatable alloys in the nucleation mechanism of the recrystallized microstructure observed in the nugget zone. Strain induced boundary migration was the dominant mechanism of microstructure evolution in the alloy, which influenced the crystallographic texture development by weakening it. Micro-texture measurements reveal variations in the crystallographic texture along the thickness of the sample. Recrystallization texture components were observed in the nugget zone indicative of a pronounced static recrystallization in the alloy as compared to the heat treatable alloys. Bulk texture measurements within the nugget zone of the optimally processed sample reveal a relatively dominant C component of shear texture. Average grain size in the nugget zone remained the same and the bulk crystallographic texture components were retained during multiple-pass FSP. The lower strain energies involved and the enhanced recovery processes due to the high temperature materials processing of the alloy during FSP resulted in a stable microstructure and texture. In summary, FSP could be promoted as a competent and suitable secondary processing technique for the bulk production of ultra-fine-grained materials in strain hardenable aluminium alloys.
Im Vortrag werden das Messprinzip des Zentrifugen-Sedimentationsverfahrens erläutert und die Anforderungen der zugrundeliegenden Normen diskutiert. Es schließen sich umfangreiche Ausführungen zur praktischen Durchführung der Messung, insbesondere auch zu den vorbereitenden Arbeiten, sowie zur Auswertung der Rohdaten an. Nach einem Vergleich der Ergebnisse mit anderen Messverfahren, wird das Verfahren in einer Zusammenfassung bewertet.
The EC’s recommendation for a definition of nanomaterial (2011/696/EU) should allow the identification of a particulate nanomaterial based on the number-based metric criterion according to which at least 50% of the constituent particles have the smallest dimension between 1 and 100 nm. However, it has been recently demonstrated that the implementation of this definition for regulatory purposes is conditioned by the large deviations between the results obtained by different sizing methods or due to practical reasons such as high costs and time-consuming (SEM, TEM).
Within the European project NanoDefine (www.nanodefine.eu) a two-tier approach has been developed, whereby firstly a screening method is applied for the rough classification as a nano-/non-nanomaterial, and for borderline cases a confirmatory method (imaging methods or field flow fractionation) must be considered.
One of the measurement methods well suited to particulate powder is the determination of volume-specific surface area (VSSA) by means of gas adsorption as well as skeletal density. The value of 60 m2/cm3 corresponding to spherical, monodisperse particles with a diameter of 100 nm constitutes the threshold for decisioning if the material is a nano- or non-nanomaterial. The correct identification of a nanomaterial by VSSA method is accepted by the EU recommendation.
However, the application of the VSSA method is associated also by some limitations. The threshold of 60 m2/cm3 is dependent on the particle shape, so that it changes considerably with the number of nano-dimensions of the particles. For particles containing micro-pores or having a microporous coating false positive results will be produced. Furthermore, broad particle size distributions make necessary to adjust the threshold. Based on examples of commercially available ceramic powders, the applicability of the VSSA approach will be tested (in relation with SEM and TEM measurements) in order to expand the actual knowledge and to improve this good available and agglomeration tolerant method.
The EU recommendation for a definition of nanomaterial (2011/696/EU) should allow the identification of a particulate nanomaterial based on the number-based metric criterion according to which at least 50% of the constituent particles have the smallest dimension between 1 and 100 nm. Within the European Project NanoDefine (www.nanodefine.eu) a two-tier approach has been developed, whereby firstly a screening method is applied for the rough classification as a nanomaterial or non-nanomaterial, and for borderline cases a confirmatory method (imaging methods or field flow fractionation) must be considered.
One of the measurement methods well suited to particulate powder is the determination of volume-specific surface area (VSSA) by means of gas adsorption as well as skeletal density. The value of 60 m2/cm3 corresponding to spherical, monodisperse particles with a diameter of 100 nm constitutes the threshold for decisioning if the material is a nanomaterial or non-nanomaterial. The correct identification of a nanomaterial by VSSA method (positive test) is accepted by the EU recommendation.
However, the application of the VSSA method is associated also by some limitations. The threshold of 60 m2/cm3 is dependent on the particle shape. For particles containing micro-pores or having a microporous coating, false positive results will be produced.
Furthermore, broad particle size distributions – as typically for ceramic materials – as well as multi-modal size distributions make necessary to adjust the threshold.
Based on examples of commercially available ceramic powders, the applicability of the VSSA approach will be tested (in relation with SEM and TEM measurements) in order to expand the actual knowledge and
improve the method.
The influence of the support structure on residual stress and distortion in SLM Inconel 718 parts
(2018)
The effect of support structure and of removal from the base plate on the residual stress state in selective laser melted IN718 parts was studied by means of synchrotron X-ray diffraction. The residual stresses in subsurface region of two elongated prisms in as-built condition and after removal from the base plate were determined. One sample was directly built on a base plate and another one on a support structure. Also, the distortion on the top surface due to stress release was measured by contact profilometry. High tensile residual stress values were found, with pronounced stress gradient along the hatching direction. In the sample on support, stress redistribution took place after removal from the base plate, as opposed to simple stress relaxation for the sample without support. The sample on support structure showed larger distortion compared to sample without support. We conclude that the use of a support decreases stress values but stress-relieving heat treatments are still needed.
Metal sulfide grain boundary precipitates of a ferrous model alloy with 13 wt.% chromium formed at 650°C under a gas atmosphere containing 0.5% SO2 and 99.5% Ar were investigated after ageing for 3 h, 6 h, and 12 h. The precipitates formed along grain boundaries were identified as Cr5S6 using energy-dispersive x-ray spectroscopy in transmission electron microscopy and electron backscatter diffraction analysis. Serial focused ion beam slicing was conducted followed by three-dimensional reconstruction to determine the number, size, and penetration depth of the precipitates evolved at the different time steps. There was a linear increase in the number of precipitates with time, while their average size increased only for the initial aging time but became constant after 6 h. Based on these results, a model for grain boundary sulfidation of ferritic alloys is discussed.
The reduction of harmful emissions to the environment is one of the most urgent challenges of our time. To achieve this goal, it is inevitable to shift from using fossil fuels to renewable energy sources. Within this transition, hydrogen can play a key role serving as fuel in transportation and as means for energy storage.
The storage and transport of hydrogen using austenitic stainless steels as the infrastructure, as well as the use of these grades in hydrogen containing aggressive environments, remains problematic. The degradation of the mechanical properties and the possibility of phase transformation by ingress and accumulation of hydrogen are the main drawbacks. Advanced studies of the behaviour of hydrogen in austenite is necessary to fully understand the occurring damage processes. This knowledge is crucial for the safe use of components in industry and transportation facilities of hydrogen.
A powerful tool for depicting the distribution of hydrogen in steels, with high accuracy and resolution, is time-of-flight secondary ion mass spectrometry (ToF-SIMS). We here present a comprehensive research on the hydrogen degradation processes in AISI 304L based on electrochemical charging and subsequent ToF-SIMS experiments. To obtain furthermore information about the structural composition and cracking behaviour, electron-backscattered diffraction (EBSD) and scanning electron microscopy (SEM) were performed afterwards. All the gathered data was treated employing data fusion, thus creating a thorough portrait of hydrogen diffusion and its damaging effects in AISI 304L.
Specimens were charged with deuterium instead of hydrogen. This necessity stems from the difficulty to separate between artificially charged hydrogen and traces existing in the material or adsorbed from the rest gas in the analysis chamber. Similar diffusion and permeation behaviour, as well as solubility, allow nonetheless to draw onclusions from the experiments.
Microplastics are increasingly entering marine, limnic and terrestrial ecosystems worldwide, where they sorb hydrophobic organic contaminants. Here, the sorption behavior of the fuel-related water contaminants benzene, toluene, ethyl benzene and xylene (BTEX) and four tertiary butyl ethers to virgin and via UV radiation aged polypropylene (PP) and polystyrene (PS) pellets was investigated. Changes in material properties due to aging were recorded using appropriate polymer characterization methods, such as differential scanning calorimetry, Fourier transform infrared spectroscopy, gel permeation chromatography, X-ray photoelectron spectroscopy, and microscopy.
Pellets were exposed to water containing BTEX and the ethers at 130-190 mg/L for up to two weeks.
Aqueous sorbate concentrations were determined by headspace gas chromatography. Sorption to the polymers was correlated with the sorbate's Kow and was significant for BTEX and marginal for the ethers.
Due to substantially lower glass transition temperatures, PP showed higher sorption than PS. Aging had no effect on the sorption behavior of PP. PS sorbed less BTEX after aging due to an oxidized surface layer.