TY - CONF A1 - Sprengel, Maximilian A1 - Ulbricht, Alexander A1 - Evans, Alexander A1 - Kromm, Arne A1 - Sommer, Konstantin A1 - Kelleher, J. A1 - Bruno, Giovanni A1 - Kannengießer, Thomas T1 - The relaxation of macroscopic residual stresses in laser powder bed fused stainless steel 316L N2 - The processing of stainless steel 316L using the additive manufacturing process Laser Powder Bed Fusion (LPBF) can widen its field of application due to a strong increase in Yield strength, without making major compromises on the ductility nor its outstanding corrosion and oxidation properties. Furthermore, improved designs that either reduce the weight or optimise the function of a part can be obtained using LPBF. These benefits are however counterbalanced by the proneness of LPBF to inducing high Residual Stresses (RS) during manufacturing. The characterisation and monitoring of these RS are of paramount importance for the wider acceptance of the LPBF process. This study focuses on the relaxation of the initial macroscopic RS present in an LPBF 316L as-built prism that undergoes various routes of manufacturing steps to achieve different specimen geometries and stress relieving treatments. The RS are determined using Angle-Dispersive (AD) and Time-of-Flight (TOF) neutron diffraction. The results reveal high tensile RS close to the surfaces and compressive RS near the centre of the as-built parts. The reduction in size and change of geometry heavily impact the stress ranges of the remaining RS, with lower stress ranges in cylindrical shaped compared to rectangular shaped specimens. Also, the application of different stress relieving heat treatments showed that heat-treating temperatures above 800 °C are necessary to obtain a strong relaxation in LPBF 316L. T2 - The second European Conference on the Structural Integrity of Additively Manufactured Materials CY - Online meeting DA - 08.09.2021 KW - Residual Stress KW - Additive Manufacturing KW - Neutron Diffraction PY - 2021 AN - OPUS4-53263 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Menneken, Martina A1 - Falk, Florian A1 - Stephan-Scherb, Christiane T1 - Early stages of corrosion in hot, aggressive environments N2 - 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. T2 - Sektionstreffen der DMG Sektionen "Angewandte Mineralogie in Umwelt & Technik" und "Chemie, Physik und Kristallographie der Minerale" CY - Bad Windsheim, Germany DA - 28.02.2018 KW - Corrosion KW - In-situ KW - EDXRD PY - 2018 AN - OPUS4-45369 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmies, Lennart A1 - Sonntag, U. A1 - Bettge, Dirk A1 - Le, Quynh-Hoa A1 - Yarysh, Anna A1 - Botsch, B. T1 - Quantitative Fraktographie unter Verwendung klassischer Verfahren, Topographie-Daten und Deep-Learning N2 - Die Analyse von Bruchflächen wird in der Schadensanalyse meist auf der Basis von Erfahrungswissen vorgenommen, welches aus vorliegenden Untersuchungen, eigenen Vergleichsversuchen und aus der Literatur stammt. Durch Vergleiche mit bereits vorliegenden Bildern werden qualitativ Bruchmechanismen ermittelt. Grundlage sind zumeist zweidimensionale Bilder aus licht- und elektronenoptischen Verfahren. Quantitative Aussagen beziehen sich bislang beispielsweise auf makroskopische Anteile von Bruchmechanismen oder die Ausmessung von Schwingstreifen. In jüngerer Zeit gibt es vermehrt Ansätze, Computer-Algorithmen einzusetzen, die in der Lage sind, unterschiedlich strukturierte Bruchmerkmale zu finden und zu klassifizieren. Im hier vorgestellten IGF-Vorhaben „iFrakto“, IGF Vorhaben Nr.: 21477 N, werden licht- und elektronen-optisch Topographie-Bilder erzeugt und die gewonnenen 3D-Informationen zusammen mit den klassischen 2D-Bildern ausgewertet. Analytische Algorithmen und Machine Learning werden eingesetzt, um Bruchmerkmale zu analysieren, zu bewerten und mit Informationen aus einer fraktographischen Datenbank zu verknüpfen. Ziel ist die Bereitstellung von Software zur Unterstützung der Fraktographie in der Schadensanalyse. In diesem Beitrag werden erste Ergebnisse des Vorhabens vorgestellt. T2 - 55. Metallographie-Tagung CY - Online meeting DA - 29.9.2021 KW - Fraktographie KW - Machine Learning KW - Datenbank KW - REM KW - Topographie PY - 2021 AN - OPUS4-53491 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Manzoni, Anna Maria A1 - Mohring, W. A1 - Karafiludis, Stephanos A1 - Schneider, M. A1 - Haas, S. A1 - Hagen, S. A1 - Glatzel, U. A1 - Laplanche, G. A1 - Stephan-Scherb, C. T1 - Corrosion in the Co-Cr-Fe-Ni high entropy alloy family N2 - While a lage amount of research on high entropy alloys is oriented towards mechanical properties and the microstructural improvement it is also necessary to keep an eye on the environment that potential application materials will be submitted to. The Co-Cr-Fe-Ni based high entropy family has shown great potential over the years of high entropy research and some candidate alloys are chosen for an insight into their corrosion behaviour. Several atmospheres are studied, i.e. O2, H2O, SO2 and a mix thereof in argon as well as synthetic air. Just as for classic alloys, the chromium is the most important element in terms of protection agains further corrosion. The addition of manganese, as in case of the “Cantor alloy” CrMnFeCoNi, overpasses Cr when it comes to oxygen affinity and thus counteracts the layer formation of Cr2O3. Even without Mn, a temperature chosen too high will also affect the formation of the chromium oxide layer and spall it off, annulling its protective potential. We can also observe how trace elements influence the layer formation. These effects and their mechanisms will be discussed for the alloys CrFeNi, CoCrNi, CrMnFeCoNi and variations of Al10Co25Cr8Fe15Ni36Ti6 using a combination of electron microscopy, thermodynamic calculations and x-ray diffraction. T2 - MRS-T International Conference CY - Hsinchu, Taiwan DA - 17.11.2023 KW - Corrosion KW - Scanning electron microscopy KW - Mixed gas atmosphere PY - 2023 AN - OPUS4-58980 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Goedecke, Caroline A1 - Altmann, Korinna A1 - Bannick, C. G. A1 - Kober, E. A1 - Ricking, M. A1 - Schmitt, T. A1 - Braun, Ulrike T1 - Detection of polymers in treated waste water using TED-GC-MS N2 - The presence of large quantities of plastic waste and its fragmentation in various environmental compartments are an important subject of current research. In the environment, (photo ) oxidation processes and mechanical abrasion lead to the formation of microplastics. However, until now, there are no established quality assurance concepts for the analysis of microplastic (<5 mm) in environmental compartments, including sampling, processing and analysis. The aim of the present work is the development of suitable examination methods and protocols (sampling, sample preparation and detection) to qualify and quantify microplastic in urbane water management systems. At first a fractional filtration system for sampling and the analytical tool, the so-called TED-GC-MS (thermal desorption gas chromatography mass spectrometry) were developed. The TED-GC-MS method is a two-step analytical procedure which consists of a thermal extraction where the sample is annealed and characteristic decomposition products of the polymers are collected on a solid phase. Afterwards these products are analysed using GC-MS. The developed fractional filtration for sampling and the TED-GC-MS for detection were used for quantitative analysis to screen the waste water influent and effluent of a Berlin waste water treatment plant for the most relevant polymers, polyethylene (PE), polypropylene (PP), polystyrene (PS), polyethylene terephthalate (PET) and polyamide (PA). The results of the study revealed that the polymeres PE, PS and PP were detected in the effluent, and PE and PS were find in the raw waste water of the sewage treatment plant in Ruhleben, Berlin. Differences in polymer types and amounts were detected at different sampling dates and within different sieve fractions. Much higher amounts of polymers were observed in the raw waste water. The peak areas of the decomposition products, used for quantification of the polymers, were adjusted using so-called response factors since the TED-GC-MS method is more sensitive for PP and PS than for PE. It has been shown that PE is the most dominant polymer in the samples. Comparing the masses of polymers in the effluent and in the raw sewage, a removal of 99 % of the polymers in the water treatment plant can be assumed. These results are consistent with the literature where removal rates between 98-99 % were described. T2 - SETAC Europe CY - Rom, Italy DA - 13.05.2018 KW - Microplastics KW - Thermogravimetry KW - Waste water KW - Chromatography PY - 2018 AN - OPUS4-44968 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Günster, Jens A1 - Zocca, Andrea T1 - Dense Powder Beds for the Additive Manufacturing of Ceramics N2 - Regarding feedstocks for the additive manufacturing (AM) of ceramics, two features are most critical in classical powder based AM processes: a high particle packing density (typically >50% TD) must be achieved with very fine particles (typically submicron) in order to ensure sufficient sintering activity. Three innovative approaches will be introduced to overcome this problem: 1. Layer wise slurry deposition: The use of water based ceramic slurries as feedstock for the additive manufacture of ceramics has many advantages which are not fully exploit yet. In the layerwise slurry deposition (LSD) process a slurry with no or low organic content is repetitively spread as thin layers on each other by means of a doctor blade. During the deposition, the ceramic particles settle on the previously deposited and dried material to form thin layers with a high packing density (55-60%). The LSD therefore shares aspects both of tape casting and slip casting. The LSD differentiates from the classical powder-based AM layer deposition, which typically achieves with a flowable coarse grained powder a low packing density (35-50%) only, consequently hindering the ability of sintering ceramic parts to full density. The LSD is coupled with the principles of selective laser sintering (SLS) or binder jetting, to generate novel processes which take advantage of the possibility of achieving a highly dense powder-bed. 2. Laser induced slip casting: Contrary to the LSD process, which requires drying of each individual layer, the direct interaction of ceramic slurries with intense laser radiation, for the laser induced slip casting (LIS), is a promising approach for the additive manufacture of voluminous parts. 3. Gas flow assisted powder deposition: By the application of a vacuum pump a gas flow is realized throughout the powder bed. This gas flow stabilizes the powder bed and results into an enhanced flowability and packing density of the powder during layer deposition. The presentation will provide a detailed discussion of potentialities and issues connected to the mentioned technologies and will describe the most recent developments in their application to technical ceramics. T2 - SmatMade 2022 CY - Osaka, Japan DA - 25.10.2022 KW - Additive Manufacturing KW - Advanced ceramics PY - 2022 AN - OPUS4-59886 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lüchtenborg, Jörg A1 - Mühler, T. A1 - Zocca, Andrea A1 - Günster, Jens T1 - Additive Manufacturing of Dense Ceramics with Laser Induced Slip Casting (LIS) N2 - The possibility to produce dense monolithic ceramic parts with additive manufacturing is at the moment restricted to small parts with low wall thickness. Up to now, 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. T2 - 42nd International Conference and Expo on Advanced Ceramics and Composites CY - Daytona Beach, FL, USA DA - 21.01.2018 KW - Additive Manufacturing KW - Ceramics PY - 2018 AN - OPUS4-44182 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Dümichen, Erik A1 - Eisentraut, Paul A1 - Braun, Ulrike T1 - Fast identification of microplastics using thermal extractions methods N2 - A new and full automated system for the analysis of microplastics in environmental samples is presented. T2 - BAM-BfR Seminar 2018 CY - Berlin, Germany DA - 15.02.2018 KW - Mikroplastik KW - TED KW - Thermal degradation PY - 2018 AN - OPUS4-44179 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Eisentraut, Paul A1 - Dümichen, Erik A1 - Braun, Ulrike T1 - Kunststoffgehalte schnell bestimmen mit der TED-GC-MS N2 - Der Vortrag behandelt die Analyse von Kunststoffen in Umweltproben mit dem thermischen Verfahren TED-GC-MS. Das Verfahren und dessen Funktionsweise werden vorgestellt, erfolgte Optimierungen, Verfahrenskenndaten sowie Möglichkeiten der Quantifizierung behandelt. T2 - Projektübergreifendes Mikroplastikseminar BASEMAN, BONUS MICROPOLL, MiWa CY - Berlin, Germany DA - 16.10.2017 KW - Mikroplastik KW - Analyse KW - TED-GC-MS PY - 2018 AN - OPUS4-43927 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Braun, Ulrike T1 - Fast identification of microplastics using thermal extraction methods N2 - The presentation presents an overview about existing methods of microplastic detection with a special focus on thermo-analytical methods. T2 - Perkin Elmer Workshop Microplastics CY - Vienna, Austria DA - 11.01.2018 KW - Microplastics KW - TED-GC-MS KW - Analysis PY - 2018 AN - OPUS4-43803 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rabe, Torsten A1 - Schulz, Bärbel A1 - Paulick, C. A1 - Kalinka, Gerhard T1 - Helical zirconia (TZP) springs manufacturing and testing under mechanical and thermal load N2 - Helical springs with a rectangular cross-section have been machined from sintered and grinded hollow cylinders with high geometrical precision and good reproducibility. Such springs made from tetragonal zirconia polycrystal (TZP) ceramic show excellent edge quality because of high fracture toughness and bending strength of the starting material. Hence, springs with desired geometric dimension and tailored spring constant can be manufactured for highly demanding applications at high temperatures and in harsh environments. Prior to any practical use, application limits of springs under mechanical and thermal load have to be analyzed. Therefore, different displacement experiments were carried out on the helical TZP springs. - Dynamic displacement tests at various temperatures from -15°C to +60°C using a piezo actor to load/unload springs with frequencies between 1 and 40 Hz: Springs remained undamaged and the spring constants were not altered, even after more than one million cycles of compression loading. - Long-time displacement measurements under static tensile loading at room temperature with a high-precision interferometer test facility: Significant spring elongation under constant strain was surprisingly proved over a period of many hours already at room temperature. - Creeping experiments for 48 h under static compression load at different temperatures up to 1000 °C: After cooling down and load removing no permanent length reduction of springs was observed for test temperatures up to 700 °C. However, reshaping of TZP springs by plastic deformation is possible at higher temperatures and opens up additional possibilities for spring design and manufacturing. T2 - German Ceramic Society, Annual Meeting 2018 CY - München, Germany DA - 09.04.2018 KW - Ceramic springs KW - Manufacturing KW - Mechanical and thermal testing PY - 2018 AN - OPUS4-44728 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Braun, Ulrike T1 - Analytik von Mikroplastik mittels TED-GC-MS N2 - Der Vortrag stellt spektroskopische und neue thermoanalytische Verfahren zum Nachweis von Mikroplastik dar. Ein spezieller Focus ist auf der Anwendung edr Verfahren für terrestrische Proben. T2 - Fachgespräch Feststoffuntersuchungen 2018 CY - Essen Werden, Germany DA - 05.03.2018 KW - Mikroplastik KW - Analytik KW - GC-MS KW - Thermische Analyse PY - 2018 AN - OPUS4-44525 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kraus, David A1 - Trappe, Volker T1 - Cyclic fatigue behavior of glass fiber reinforced epoxy resin at ambient and elevated temperatures N2 - 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. T2 - ECCM18 - 18th European conference on composite materials CY - Athens, Greece DA - 24.06.2018 KW - Composite KW - Fatigue KW - Thermomechanics KW - Residual stresses KW - Temperature PY - 2018 AN - OPUS4-45346 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gaal, Mate A1 - Schadow, Florian A1 - Nielow, Dustin A1 - Trappe, Volker T1 - Prüfung von Rotorblattschalen mit Luftultraschall N2 - 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. T2 - DGZfP-Jahrestagung CY - Leipzig, Germany DA - 07.05.2018 KW - Wandler KW - Rotorblattschalen KW - Luftultraschall KW - Ferroelektret PY - 2018 AN - OPUS4-45307 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Zocca, Andrea A1 - Lima, Pedro A1 - Lüchtenborg, Jörg A1 - Mühler, T. A1 - Diener, S. A1 - Katsikis, N. A1 - Günster, Jens T1 - LSD- 3D printing: Powder based Additive Manufacturing, from porcelain to technical ceramics N2 - Powder based Additive Manufacturing (AM) processes are widely used for metallic and polymeric materials, but rarely commercially used for ceramic materials, especially for technical ceramics. This seemingly contradicting observation is explained by the fact that in powder based AM, a dry flowable powder needs to be used. Technical ceramics powders are in fact typically very fine and poorly flowable, which makes them not suitable for AM. The layerwise slurry deposition (LSD) is an innovative process for the deposition of powder layers with a high packing density for powder based AM. In the LSD process, a ceramic slurry is deposited to form thin powder layers, rather than using a dry powder This allows the use of fine powders and achieves high packing density (55-60%) in the layers after drying. When coupled with a printing head or with a laser source, the LSD enables novel AM technologies which are similar to *Denotes Presenter 42nd International Conference & Exposition on Advanced Ceramics & Composites 127 Abstracts the 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. This presentation will give an overview of the milestones in the development of this technology, with focus on the latest results applied both to silicate and to technical ceramics. T2 - 42nd International Conference & Exposition on Advanced Ceramics and Composites CY - Daytona, FL, USA DA - 21.01.2018 KW - Additive Manufacturing KW - 3D printing KW - Ceramic KW - Alumina KW - Porcelain KW - Silicon Carbide PY - 2018 AN - OPUS4-44017 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - von Hartrott, P. A1 - Rockenhäuser, Christian A1 - Schriever, Sina A1 - Metzger, M. A1 - Skrotzki, Birgit T1 - Correlation of the precipitate size evolution and the creep rate of the aluminum alloy EN AW 2618A at 190 °C N2 - Ther results of research on correlation of precipitate size Evolution and the creep rate of the Aluminium alloy EN AW 2618A at 190 °C was presented. T2 - ICAA16 CY - Montreal, Canada DA - 17.06.2018 KW - Alloy 2618A KW - Creep KW - Aluminium KW - Coarsening PY - 2018 AN - OPUS4-45283 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rockenhäuser, Christian A1 - Augenstein, E. A1 - Skrotzki, Birgit T1 - Long term ageing of alloy 2618A N2 - Results of the in vestigation of the "Long term ageing of alloy 2618A" were presented. T2 - ICAA 16 CY - Montreal, Canada DA - 17.06.2018 KW - Alloy 2618A KW - Aluminium KW - Coarsening KW - Transmission electron microscopy KW - S-phase PY - 2018 AN - OPUS4-45288 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Höhne, Patrick A1 - Kuchenbecker, Petra A1 - Lindemann, Franziska A1 - Güther, Wolfgang A1 - Rabe, Torsten T1 - Strategies to improve spray dried multi-component granules N2 - Dry pressing of ceramic materials requires homogeneously soft granules with good flowability to allow rapid die filling and to avoid packing defects. Spray-drying granulation appears to be the best method for obtaining granules with high flowability in industrial scale. But, strength reducing internal microstructural defects caused by spray-dried granules with hollow and hard shells are often observed using nano and/or multi-component starting powders. Using the example of a ZTA composite, the potential of slurry optimization, ultrasound atomization and infrared drying for better granule properties and compaction behavior were investigated. Starting granules produced in a conventional spray dryer (Niro, Denmark) with a two fluid nozzle showed typical defects like large central pores and dimples. The early step of slurry preparation already possesses an essential optimization possibility in the form of stability adjustments. Granule compaction was clearly improved upon a specific reduction in slurry stability. The second optimization opportunity to improve the granule quality was the atomization step. Implementation of an ultrasound atomizing unit into the conventional spray dryer positively affected granule size distribution and therefor flowability and as well granule yield. But, a combination of both process optimizations delivered the best sinter bodies with highest density and strength due to further reduction in maximum size and fraction of pores. As last step of a spray drying process, the drying is the focus of further investigations. A current setup implying a spray dryer prototype utilizes stacked infrared heater in a countercurrent setup delivering a further increase in granule yield and enduring spraying process stability. T2 - 93. Jahrestagung der Deutschen Keramischen Gesellschaft CY - München, Germany DA - 10.04.2018 KW - Spray drying KW - Granules KW - Destabilization KW - Ultrasound PY - 2018 AN - OPUS4-44700 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rockenhäuser, Christian A1 - von Hartrott, P. A1 - Metzger, M. A1 - Schriever, Sina A1 - Augenstein, E. A1 - Karlin, J. A1 - Piesker, Benjamin A1 - Schweizer, C. A1 - Skrotzki, Birgit T1 - Lifetime Assessment of Aluminium radial compressor wheels considering material ageing N2 - The results of the project "Lifetime Assessment of Aluminium radial compressor wheels considering material ageing" were presented. T2 - FVV Frühjahrstagung 2018 CY - Bad Neuenahr, Germany DA - 22.03.2018 KW - Alloy 2618A KW - Degradation KW - S-phase KW - Dark-field transmission electron microscopy KW - Aluminum PY - 2018 AN - OPUS4-44706 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Reinsch, Stefan A1 - Müller, Ralf T1 - Surface-induced Crystallization of Glass N2 - 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. T2 - Glasforum der Deutschen Glastechnischen Gesellschaft (DGG) CY - Würzburg, Germany DA - 11.06.2018 KW - Crystallization KW - Silicate Glasses KW - Surface Nucleation PY - 2018 AN - OPUS4-45593 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -