5 Werkstofftechnik
Filtern
Erscheinungsjahr
- 2018 (88) (entfernen)
Dokumenttyp
- Vortrag (88) (entfernen)
Referierte Publikation
- nein (88) (entfernen)
Schlagworte
- Additive Manufacturing (7)
- Glass (6)
- Additive manufacturing (5)
- Alloy 2618A (4)
- Aluminium (4)
- CCUS (4)
- Coarsening (4)
- Crack growth (4)
- Creep (4)
- DCB (4)
- Fatigue (4)
- Vickers (4)
- Water speciation (4)
- Carbon steels (3)
- Corrosion (3)
- Degradation (3)
- Droplet corrosion (3)
- Martensitic steel (3)
- Mikroplastik (3)
- Powder (3)
- S-phase (3)
- Superaustenite steel (3)
- Supercritical/dense phase CO2 (3)
- Transmission electron microscopy (3)
- Wasser (3)
- Alumina (2)
- Ceramic (2)
- Concrete (2)
- Dark-field transmission electron microscopy (2)
- Ferritic-martensitic steels (2)
- Foaming (2)
- Fraktographie (2)
- Hochtemperatur (2)
- LCF (2)
- Microplastics (2)
- Neutron diffraction (2)
- PE-HD (2)
- Residual Stresses (2)
- Ressidual stress (2)
- Rotor blade (2)
- Sandwich (2)
- Selective Laser Melting (2)
- Sinter additive (2)
- Sintering (2)
- Soda-lime silicate glass (2)
- TED-GC-MS (2)
- Thermoelectrics (2)
- UV-irradiation (2)
- Wind turbine blades (2)
- XANES (2)
- 3D glass structure model (1)
- 3D printing (1)
- 3D-printing (1)
- 9-12% Cr ferritic-martensitic steels (1)
- Accelerated integration scheme (1)
- Active thermography (1)
- Age hardening (1)
- Aggressive gases (1)
- Air-coupled ultrasonic testing (1)
- Airborne ultrasonic testing (1)
- Al-Li alloys (1)
- Aluminum (1)
- Analyse (1)
- Analysis (1)
- Analytik (1)
- Analytische Zentrifuge (1)
- Anisotropy (1)
- Betriebsfestigkeit (1)
- Biodiesel (1)
- CCS (1)
- Calcination (1)
- Calciumcobaltit (1)
- Calciummanganat (1)
- Carbon steels (1)
- Carbon capture (1)
- Carbon dioxide (1)
- Ceramic springs (1)
- Ceramics (1)
- Chromatography (1)
- Complex loading (1)
- Composite (1)
- Composites (1)
- Continnum damage model (1)
- Crack (1)
- Creep-fatigue (1)
- Crystal Orientation (1)
- Crystal plasticity (1)
- Crystallization (1)
- Cycle jump (1)
- Cyclic oxidation (1)
- Cyclic softening (1)
- Damage (1)
- Dark-field transmission electron microscopy (DFTEM) (1)
- Data Fusion (1)
- Destabilization (1)
- Dielectric strength (1)
- Diesel (1)
- Diffraction (1)
- Diffraction contrast (1)
- Diffusion (1)
- Diffusion coefficient (1)
- Dislocation (1)
- Dissolved water (1)
- EBSD (1)
- EDXRD (1)
- Electron microscopy (1)
- FCH JU (1)
- Faserverstärkte Kunstoffe (1)
- Fatigue damage (1)
- Fatigue fracture (1)
- Fatigue of sandwich shell structures (1)
- Fatigue of sandwich structures (1)
- Ferroelectret (1)
- Ferroelektret (1)
- Fertigungstechnologie (1)
- Formerkennung (1)
- GC-MS (1)
- Gasabgabe (1)
- Gasgehalt (1)
- Geopolymers (1)
- Glas (1)
- Glass composition (1)
- Glass fiber reinforced polymers (1)
- Grain boundaries (1)
- Granules (1)
- High Temperature Corrosion (1)
- High temperature corrosion (1)
- High-temperature corrosion (1)
- Horizon 2020 (1)
- Hot Press (1)
- Hydrogen permeation (1)
- Implant failures (1)
- Impurities (1)
- In situ (1)
- In-situ (1)
- Inconel 686 coating (1)
- Initial attachment (1)
- Injection (1)
- Inverse ostwald ripening (1)
- Kalzinierung (1)
- Kennwertermittlung (1)
- Keramikfeder (1)
- Kriechen (1)
- Kunststoffe (1)
- Laser (1)
- Laser cladding (1)
- Laser curing (1)
- Lebensdauer (1)
- Lightweight materials (1)
- Long-term storage (1)
- Low cycle fatigue (1)
- Luftultraschall (1)
- Manufacturing (1)
- Martensitic steel (1)
- Material defects (1)
- Mechanical and thermal testing (1)
- Mechanisches Verhalten (1)
- Metallic components (1)
- Micro-shrinkages (1)
- Micromechanical model (1)
- Microstructural evolution (1)
- Microstructure (1)
- Multiaxial stress state (1)
- Multilayer (1)
- Multilayer technology (1)
- Nano particle (1)
- Nano screening (1)
- Ni-Resist (1)
- Nickel-base superalloy (1)
- Nickel-base superalloys (1)
- Non-destructive testing (1)
- P92 steels (1)
- Particle size (1)
- Partikelgrößenverteilung (1)
- Phase field simulation (1)
- Phase-field simulation (1)
- Polymerwissenschaften (1)
- Porcelain (1)
- Precipitates (1)
- Precipitation (1)
- Pressure-assisted sintering (1)
- Rafting (1)
- Relaxation (1)
- Relaxationsphänomene (1)
- Residual stresses (1)
- Risswachstum (1)
- Rotorblattschalen (1)
- SLM (1)
- Safety assessment (1)
- Scale-bridging (1)
- Scanning transmission electron microscopy (STEM) (1)
- Schwingbrüche (1)
- Schädigung (1)
- Silicate Glasses (1)
- Silicatglas (1)
- Silicon Carbide (1)
- Simulation of concrete (1)
- Single-crystals (1)
- Sinterung (1)
- Spannungs-Dehnungs-Verhalten (1)
- Spray drying (1)
- Structured heating (1)
- Struktur (1)
- Subsurface defects (1)
- Sulfidation (1)
- Superalloy single crystals (1)
- Superaustenite steel (1)
- Supercritical/dense phase CO 2 (1)
- Surface Nucleation (1)
- TAHYA (1)
- TED (1)
- TMF (1)
- Temperature (1)
- Texturation (1)
- Thermal degradation (1)
- Thermische Analyse (1)
- Thermo-mechanical fatigue (1)
- Thermoanalytical Methods (1)
- Thermoelectric generator (1)
- Thermoelectric oxide (1)
- Thermoelektrika (1)
- Thermographie (1)
- Thermogravimetry (1)
- Thermomechanics (1)
- Thermomechanische Eigenschaften (1)
- Ultrasound (1)
- Under cyclic loading (1)
- VCSEL (1)
- VSSA (1)
- Virtual experiments (1)
- Viscoplasticity (1)
- Wandler (1)
- Waste water (1)
- Wind turbine (1)
- Withstand voltage tests (1)
- X-ray laminography (1)
- Zyklische Belastung (1)
Organisationseinheit der BAM
- 5 Werkstofftechnik (88) (entfernen)
Eingeladener Vortrag
- nein (88)
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.
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.
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.
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.
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.
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.
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.