5 Werkstofftechnik
Filtern
Dokumenttyp
- Zeitschriftenartikel (52) (entfernen)
Sprache
- Englisch (52) (entfernen)
Referierte Publikation
- nein (52) (entfernen)
Schlagworte
- Corrosion (7)
- Additive manufacturing (6)
- Additive Manufacturing (4)
- CCS (4)
- Steel (4)
- Corrosion Fatigue (3)
- High alloyed steel (3)
- Alkali zinc borate glasses (2)
- Aquifer (2)
- Binder Jetting (2)
- Carbon storage (2)
- Corrosion fatigue (2)
- Crystallization (2)
- Damage (2)
- Glass (2)
- Heat treatment (2)
- High Alloyed Steel (2)
- Layerwise Slurry Deposition (2)
- Lead borate glasses (2)
- Nanoparticles (2)
- Pitting (2)
- Solubility (2)
- Viscosity (2)
- 150 Years (1)
- 2PP (1)
- 3D-printing (1)
- ATZ (1)
- Acid-leaching (1)
- Adolf Martens (1)
- Advanced wastewater treatment (1)
- Agglomerates (1)
- Aging (1)
- Al2O3 (1)
- Alkali-activated materials (1)
- Alpha-tricalcium phosphate (1)
- Alumina toughened zirconia (1)
- Aluminosilicate glasses (1)
- Aluminum alloy (1)
- Amorphous silica (1)
- Annealing (1)
- Bio-ceramic engineering (1)
- Bioactive glass (1)
- Blended learning (1)
- Bond energy (1)
- Brown-rot fungi (1)
- CALPHAD (1)
- Cabon capture and storage (1)
- Carbidic austempered ductile iron (1)
- Carbon capture and storage (1)
- Ccs (1)
- Ceramic (1)
- Ceramic nano particles (1)
- Ceramics (1)
- Ceramics 3D printing (1)
- Co2-Storage (1)
- Coating (1)
- Composite (1)
- Coniophora puteana (1)
- Corrosion mechanism (1)
- CrMnFeCoNi (1)
- Crack propagation (1)
- Creep (1)
- Critical energy release rate (1)
- Crystal lattice (1)
- Cubical shape (1)
- Cytocompatibility (1)
- Defect detection (1)
- Density-based Model (1)
- Dentine (1)
- Diffusion (1)
- Diffusivity (1)
- Dispersion process (1)
- Diversity (1)
- Ductile iron (1)
- EBSD (1)
- Electrochemical deposition (1)
- Electron diffraction (1)
- Electron microscopy (1)
- Enamel (1)
- Endurance Limit (1)
- Environmentally assisted cracking (1)
- Fatigue (1)
- Fluoride nanoparticles (1)
- Fluorolytic sol−gel (1)
- Fourier transform infrared spectroscopy (1)
- Fracture mechanics (1)
- Fracture surface energy (1)
- Fragility (1)
- Gas flow assisted powder deposition (1)
- General Chemistry (1)
- Geometrical factors (1)
- Glass fiber reinforced polymer (1)
- Glass liner (1)
- Glass powder (1)
- Grain boundary engineering (1)
- High Cycle Fatigue (1)
- High entropy alloy (1)
- Hot isostatic pressing (HIP) (1)
- Hybrid Manufacturing (1)
- Hydrogen permeation (1)
- Hydrogen storage tank (1)
- IR spectroscopy (1)
- Inconel 625 (1)
- Indentation hardness (1)
- Interface (1)
- Interfacial shear strength (1)
- Inverted classroom (1)
- Ionic porosity (1)
- Iron oxide (1)
- Kikuchi diffraction (1)
- Laser ablation in liquid (1)
- Laser-induced slip casting (1)
- Lattice misfit (1)
- Lattices (1)
- Lecture films (1)
- Lifetime prediction (1)
- Lithography-based technologies (1)
- Martensitic steel (1)
- Mass transport (1)
- Materials Chemistry (1)
- Mechanical Engineering (1)
- Mechanics of Materials (1)
- Metals and Alloys (1)
- Microsegregation (1)
- Microstructure (1)
- Microstructure Design (1)
- Molecular Dynamics (1)
- Molecular dynamics (1)
- Nano CRM (1)
- Nano-ceramic-additive-manufacturing photoresin (1)
- Nano-powder (1)
- NanoCAM (1)
- Networking (1)
- Niobium alloying (1)
- Nucleation tendency (1)
- Nydrogen melting (1)
- Particle morphology (1)
- Pattern matching (1)
- Permeability (1)
- Phase-field (1)
- Physical properties (1)
- Phytolith (1)
- Polyaniline (1)
- Polymer matrix composites (1)
- Polymer-ceramic mixtures (1)
- Porosity (1)
- Portfolio (1)
- Powder bed density (1)
- Powder-based processes (1)
- Powdered activated carbon (1)
- Process (1)
- Pull-out composite materials (1)
- Quality assurance (1)
- Raman spectroscopy (1)
- Reference nanoparticles (1)
- Resistance stress (1)
- Rhodonia placenta (1)
- Roughness (1)
- SAXS (1)
- SEM wood characterization (1)
- Scaffold (1)
- SchwarzP cells (1)
- Segregation Engineering (1)
- Sewage treatment plant (1)
- Shear thinning (1)
- Single crystal superalloys (1)
- Sinter retardation (1)
- Sintering (1)
- Size (1)
- Sliding simulation (1)
- Slip-rolling (1)
- Slurry (1)
- Soda lime silicate glass (1)
- Space (1)
- Steels (1)
- Surface (1)
- Surface roughness (1)
- Surface-induced Melting (1)
- Technical Ceramics (1)
- Temperature (1)
- Thermo-mechanics (1)
- Thermoanalysis (1)
- Thermogravimetry (1)
- Thin tribofilm (1)
- Titanium oxide (1)
- Tooth wear (1)
- Transmission electron microscopy (1)
- Two-photon adsorption (1)
- Two-photon polymerization (1)
- Vacancies (1)
- Viscous sintering (1)
- Water in glass (1)
- Wood protection (1)
- X-ray diffraction (1)
- Young’s Modulus (1)
- bioactive (1)
- biomaterials (1)
- bone (1)
- corrosion (1)
- high entropy alloys (1)
- hydrogen storage (1)
- oxidation (1)
- scanning electron microscopy (1)
- sulfidation (1)
Organisationseinheit der BAM
- 5 Werkstofftechnik (52)
- 5.1 Mikrostruktur Design und Degradation (18)
- 5.4 Multimateriale Fertigungsprozesse (14)
- 5.6 Glas (10)
- 6 Materialchemie (9)
- 5.2 Metallische Hochtemperaturwerkstoffe (4)
- 5.3 Polymere Verbundwerkstoffe (4)
- 5.5 Materialmodellierung (4)
- 6.3 Strukturanalytik (4)
- 7 Bauwerkssicherheit (4)
Instead of foreseeing and preparing for all possible scenarios of machine failures, accidents, and other challenges arising in space missions, it appears logical to take advantage of the flexibility of additive manufacturing for “in-space manufacturing” (ISM). Manned missions into space rely on complicated equipment, and their safe operation is a great challenge. Bearing in mind the absolute distance for manned missions to the Moon and Mars, the supply of spare parts for the repair and replacement of lost equipment via shipment from Earth would require too much time. With the high flexibility in design and the ability to manufacture ready-to-use components directly from a computer-aided model, additive manufacturing technologies appear to be extremely attractive in this context. Moreover, appropriate technologies are required for the manufacture of building habitats for extended stays of astronauts on the Moon and Mars, as well as material/feedstock. The capacities for sending equipment and material into space are not only very limited and costly, but also raise concerns regarding environmental issues on Earth. Accordingly, not all materials can be sent from Earth, and strategies for the use of in-situ resources, i.e., in-situ resource utilization (ISRU), are being
envisioned. For the manufacturing of both complex parts and equipment, as well as for large infrastructure, appropriate technologies for material processing in space need to be developed.
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.
Spherical mesoporous bioactive glasses in the silicon dioxide (SiO2)-phosphorus pentoxide (P2O5)–calcium oxide (CaO) system with a high specific surface area of up to 300m2/g and a medium pore radius of 4 nm were synthesized by using a simple one-pot surfactant-assisted sol–gel synthesis method followed by calcination at 500–700°C. The authors were able to control the particle properties by varying synthesis parameters to achieve microscale powders with spherical morphology and a particle size of around 5–10 mm by employing one structure-directing agent. Due to a high Calcium oxide content of 33·6mol% and a phosphorus pentoxide content of 4·0mol%, the powder showed very good bioactivity up to 7 d of immersion in simulated Body fluid. The resulting microspheres are promising materials for a variety of life science applications, as further processing – for example, granulation – is unnecessary. Microspheres can be applied as materials for powder-based additive manufacturing or in stable suspensions for drug release, in bone cements or fillers.
Trace elements play an important role in the fine-tuning of complex material properties. This study focuses on the correlation of microstructure, lattice misfit and creep properties. The compositionally complex alloy Al10Co25Cr8Fe15Ni36Ti6 (in at. %) was tuned with high melting trace elements Hf and W. The microstructure consists of a γ matrix, γ' precipitates and the Heusler phase and it is accompanied by good mechanical properties for high temperature applications. The addition of 0.5 at.% Hf to the Al10Co25Cr8Fe15Ni36Ti6 alloy resulted in more sharp-edged cubic γ′ precipitates and an increase in the Heusler phase amount. The addition of 1 at.% W led to more rounded γ′ precipitates and the dissolution of the Heusler phase. The shapes of the γ' precipitates of the alloys Al9.25Co25Cr8Fe15Ni36Ti6Hf0.25W0.5 and Al9.25Co25Cr8Fe15Ni36Ti6Hf0.5W0.25, that are the alloys of interest in this paper, create a transition from the well-rounded precipitates in the alloy with 1% W containing alloy to the sharp angular particles in the alloy with 0.5% Hf. While the lattice misfit has a direct correlation to the γ' precipitates shape, the creep rate is also related to the amount of the Heusler phase. The lattice misfit increases with decreasing corner radius of the γ' precipitates. So does the creep rate, but it also increases with the amount of Heusler phase. The microstructures were investigated by SEM and TEM, the lattice misfit was calculated from the lattice parameters obtained by synchrotron radiation measurements.
We discuss a refined simulation approach which treats Kikuchi diffraction patterns in electron backscatter diffraction (EBSD) and transmission Kikuchi diffraction (TKD). The model considers the result of two combined mechanisms: (a) the dynamical diffraction of electrons emitted coherently from point sources in a crystal and (b) diffraction effects on incoherent diffuse intensity distributions. Using suitable parameter settings, the refined simulation model allows to reproduce various thickness- and energy-dependent features which are observed in experimental Kikuchi diffraction patterns. Excess-deficiency features are treated by the effect of gradients in the incoherent background intensity. Based on the analytical two-beam approximation to dynamical electron diffraction, a phenomenological model of excess-deficiency features is derived, which can be used for pattern matching applications. The model allows to approximate the effect of the incident beam geometry as a correction signal for template patterns which can be reprojected from pre-calculated reference data. As an application, we find that the accuracy of fitted projection centre coordinates in EBSD and TKDcan be affected by changes in the order of 10−3–10−2 if excess-deficiency
features are not considered in the theoreticalmodel underlying a best-fit pattern matching approach. Correspondingly, the absolute accuracy of simulation-based EBSD strain determination can suffer frombiases of a similar order of magnitude if excess-deficiency effects are neglected in the simulation model.
This paper investigates fast and inexpensive measurement methods for defect detection in parts produced by Additive Manufacturing (AM) with special focus on lattice parts made of ceramics. By Lithography-based Ceramic Manufacturing, parts were built both without defects and with typical defects intentionally introduced. These defects were investigated and confirmed by industrial X-ray Computed Tomography. Alternative inexpensive methods were applied afterwards on the parts such as weighing, volume determination by Archimedes method and gas permeability measurement. The results showed, that defects resulting in around 20% of change in volume and mass could be separated from parts free of defects by determination of mass or volume. Minor defects were not detectable as they were in the range of process-related fluctuations. Permeability measurement did not allow to safely identify parts with defects. The measurement methods investigated can be easily integrated in AM process chains to support quality control.
Physical storage of gaseous hydrogen under high-pressure in glassy micro-containers such as spheres and capillaries is a promising concept for enhancing safety and the volumetric capacity of mobile hydrogen storage systems. As very low permeation through the container wall is required for storage of compressed hydrogen, development of glasses of minimal hydrogen permeability is needed. For this purpose, one has to understand better the dependence of hydrogen permeability on glass structure. The paper points out that minimizing the accessible free volume is as one strategy to minimize hydrogen permeability. Based on previously measured and comprehensive literature data, it is shown that permeation is independently controlled by ionic porosity and network modifier content. Thus, ionic porosity in modified and fully polymerized networks can be decreased equally to the lowest hydrogen permeability among the glasses under study. Applying this concept, a drop of up to 30,000 with respect to the permeation of hydrogen molecules through silica glass is attainable.
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.
Wood treated with nano metal fluorides is found to resist fungal decay. Sol−gel synthesis was used to synthesize MgF2 and CaF2 nanoparticles. Electron microscopy images confirmed the localization of MgF2 and CaF2 nanoparticles in wood. Efficacy of nano metal fluoride-treated wood was tested against brown-rot fungi Coniophora puteana and Rhodonia placenta. Untreated wood specimens had higher
mass losses (∼30%) compared to treated specimens, which had average mass loss of 2% against C. puteana and 14% against R. placenta, respectively. Nano metal fluorides provide a viable alternative to current wood preservatives.
We present an easy-to-apply method to predict structural trends in the internal nucleation tendency of oxide glasses. The approach is based on calculated crystal fracture surface energies derived from easily accessible diatomic bond energy and crystal lattice data. The applicability of the method is demonstrated on literature nucleation data for isochemically crystallizing oxide glasses.