TY - CONF A1 - Dittmann, Daniel A1 - Braun, Ulrike A1 - Jekel, M. A1 - Ruhl, A. S. T1 - Thermoanalytische Verfahren in der Umweltanalytik: Neue Methoden für die weitergehende Abwasserbehandlung mit Aktivkohle N2 - Motivation: > Zunehmender Einsatz von Pulveraktivkohle (PAK) zur Spurenstoffelimination in kommunalen Kläranlagen > Bisher keine analytische Methode zur Quantifizierung von PAK in Belebungsbecken, bzw. in Gegenwart von Belebtschlamm > Anwendung der Thermogravimetrischen Analyse (TGA) zur Feststoffcharakterisierung auf Umweltfragestellungen Ergebnisse: > Quantifizierung von PAK in Belebtschlamm ist möglich und kann über unterschiedliche zweistufige TGA-Methoden erfolgen > Zersetzungsgasanalyse zeigt veränderte und verzögerte Freisetzung aliphatischer Produkte des Belebtschlamms T2 - Wasser 2018 CY - Papenburg, Germany DA - 07.05.2018 KW - Thermogravimetrie KW - Belebtschlamm KW - Infrarotspektroskopie KW - Thermoanalyse KW - Pulveraktivkohle PY - 2018 AN - OPUS4-44974 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dittmann, Daniel A1 - Braun, Ulrike A1 - Jekel, M. A1 - Ruhl, A. S. T1 - Quantification and characterisation of activated carbon in activated sludge by thermogravimetric and evolved gas analyses N2 - Advanced wastewater treatment with powdered activated carbon (PAC) leads to a spread of PAC into different purification stages of wastewater treatment plants (WWTP) due to recirculation and filter back-wash. Currently, no methods for quantification of PAC in activated sludge are available. In this study, PAC containing activated sludge from four WWTP were examined by two-step thermogravimetric analysis (TGA) with heating up to 600°C in N2 and subsequently in synthetic air. Direct quantification of PAC according to temperature specific weight losses was possible for one WWTP. Quantification by combining specific mass losses was found to be an alternative direct method, with a detection limit of 1.2% PAC in dry sample mass. Additionally, evolved gas analysis (EGA) by infrared-spectroscopy (FTIR) during TGA revealed interaction mechanisms between PAC and activated sludge. Aliphatic compounds from activated sludge were identified as major substances influenced by PAC. In derivative thermogravimetry (DTG), a typical double peak at approximately 300°C was found to be related to carbonylic species with increased evolution of acetic acid in aged activated sludge. TGA and EGA are promising tools to understand, control and optimise the application of PAC in advanced wastewater treatment. KW - Advanced wastewater treatment KW - Powdered activated carbon KW - Sewage treatment plant KW - Thermoanalysis KW - Thermogravimetry KW - Fourier transform infrared spectroscopy PY - 2018 UR - http://www.sciencedirect.com/science/article/pii/S2213343718301313 DO - https://doi.org/10.1016/j.jece.2018.03.010 SN - 2213-3437 VL - 6 IS - 2 SP - 2222 EP - 2231 PB - Elsevier CY - Amsterdam AN - OPUS4-44978 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mueller, Axel A1 - Duemichen, E. A1 - Eisentraut, Paul A1 - Braun, Ulrike A1 - Scholz, K. A1 - Bannick, C.-G. T1 - Analysing microplastics in samples of terrestrial systems N2 - The presence, fate and effects of microplastics (MP) in terrestrial systems are largely unknown. The few existing studies investigated either agricultural or industrial sites. Several techniques were used for analysis, primarly spectroscopic methods such as FTIR or Raman. Sample pretreatments like density separations are common to reduce matrix. A lack of harmonised and standardised sampling instructions for microplastic investigations in the terrestrial area was identified as particular critical, because different studies are barely comparable. The aim of the project is to develop a proposal for a harmonized procedure for sampling, sample preparation and the detection of microplastics in terrestrial matrices for total content determination. By detecting specific degradation products the thermal extraction desorption gas chromatography mass spectrometry (TED-GC-MS) allows a direct determination of mass content of MP in environmental samples. T2 - SETAC 2018 CY - Rome, Italy DA - 13.05.2018 KW - Microplastics KW - Soil sample KW - TED-GC-MS KW - Analysis PY - 2018 AN - OPUS4-44988 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dittmann, Daniel T1 - Charakterisierung und selektive Quantifizierung von Aktivkohle N2 - Pulveraktivkohle (PAK) ist für die Spurenstoffelimination in der kommunalen Abwasserbehandlung sehr bedeutsam. Eine neue Methode hilft die PAK-Konzentration im Belebungsbecken einer Kläranlage analytisch zu bestimmen und bietet Möglichkeiten Adsorptionsmechanismen besser zu verstehen. KW - Thermogravimetrie KW - Pulveraktivkohle KW - Infrarotspektroskopie PY - 2018 SN - 1438-5716 SN - 0043-0986 VL - 68 IS - 4 SP - 16 EP - 17 PB - Huss-Medien GmbH CY - Berlin AN - OPUS4-45030 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 - JOUR A1 - Scheuerlein, C. A1 - Finn, Monika A1 - Meyer, Christian A1 - Lackner, F. A1 - Savary, F. A1 - Rehmer, Birgit T1 - Thermomechanical Behavior of the HL-LHC 11 Tesla Nb3Sn Magnet Coil Constituents During Reaction Heat Treatment N2 - The knowledge of the temperature-induced changes of the superconductor volume and of the thermomechanical behavior of the different coil and tooling materials is required for predicting the coil geometry and the stress distribution in the coil after the Nb3Sn reaction heat treatment. In this paper, we have measured the Young’s and shear moduli of the HL-LHC 11 T Nb3Sn dipole magnet coil and reaction tool constituents during in situ heat cycles with the dynamic resonance method. The thermal expansion behaviors of the coil components and of a free standing Nb3Sn wire were compared based on dilation experiments. KW - Superconducting magnet KW - Young`s modulus KW - Thermal expansion KW - Stress-strain-behavior PY - 2018 DO - https://doi.org/10.1109/TASC.2018.2792485 SN - 1051-8223 SN - 1558-2515 VL - 28 IS - 3 SP - 4003806 - 1 EP - 4003806 - 6 PB - IEEE Council on Superconductivity CY - New York AN - OPUS4-44020 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wisniewski, W. A1 - Thieme, C. A1 - Müller, Ralf A1 - Reinsch, Stefan A1 - Groß-Barsnick, S.-M. A1 - Rüssel, C. T1 - Oriented surface nucleation and crystal growth in a 18BaO·22CaO·60SiO2 mol% glass used for SOFC seals N2 - A glass of the composition 37BaO·16CaO·47SiO2 wt% produced on an industrial scale is crystallized at 970 °C for times ranging from 15 min to 2 h. The crystallization at the immediate surface as well as the crystal growth into the bulk are analyzed using scanning electron microscopy (SEM) including energy dispersive X-ray spectroscopy (EDXS) and electron backscatter diffraction (EBSD) as well as X-ray diffraction in the Θ–2Θ setup (XRD). The immediate surface shows the oriented nucleation of walstromite as well as the formation of wollastonite and an unknown phase of the composition BaCaSi3O8. All three phases also grow into the bulk where walstromite ultimately dominates the kinetic selection and grows throughout the bulk due to a lack of bulk nucleation. Walstromite shows systematic orientation changes as well as twinning during growth. A critical analysis of the XRD-patterns acquired from various crystallized samples indicates that their evaluation is problematic and that phases detected by XRD in this system should be verified by another method such as EDXS. KW - Glass KW - Surface nucleation KW - Orientation KW - EBSD PY - 2018 DO - https://doi.org/10.1039/c7ce02008b VL - 20 IS - 6 SP - 787 EP - 795 PB - Royal Society of Chemistry AN - OPUS4-44405 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 - von Hartrott, P. A1 - Rockenhäuser, Christian A1 - Schriever, Sina A1 - Skrotzki, Birgit T1 - Correlation of the precipitate size evolution and the creep rate of the aluminium alloy EN AW 2618A at 190 °C N2 - A short description of the work done on the topic "Correlation of the precipitate size evolution and the creep rate of the aluminium alloy EN AW 2618A at 190 °C" is given. T2 - International Conference on Aluminium Alloys 16 CY - Montreal, Canada DA - 17.06.2018 KW - Alloy 2618A KW - Degradation KW - Aluminium KW - Creep KW - Coarsening PY - 2018 SN - 978-1-926872-41-4 SP - 99 AN - OPUS4-45284 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 - The result of an Investigation of the "Long term ageing of alloy 2618A" are discussed. T2 - International Conference on Aluminium Alloys 16 CY - Montreal, Canada DA - 17.06.2018 KW - Alloy 2818A KW - Aluminium KW - Coarsening KW - Transmission electron microscopy KW - S-phase PY - 2018 SP - Paper 400101 AN - OPUS4-45287 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 - JOUR A1 - Epishin, A. A1 - Bokstein, B. A1 - Svetlov, I. A1 - Fedelich, Bernard A1 - Feldmann, Titus A1 - Le Bouar, Y. A1 - Ruffini, A. A1 - Finel, A. A1 - Viguier, B. A1 - Poquillon, D. T1 - A vacancy model for pore annihilation during hot isostatic pressing of single-crystal nickel-base superalloys N2 - An improved diffusion model is proposed for pore annihilation during HIP of single-crystal nickel-base superalloys. The model assumes the pore dissolution by emission of vacancies and their sink to the low angle boundaries. Calculation, considering distribution of the pore sizes, predicts the kinetics of pore annihilation similar to the experimental one. KW - Single crystal superalloys KW - Hot isostatic pressing (HIP) KW - Porosity KW - Diffusion KW - Vacancies PY - 2018 DO - https://doi.org/10.1134/S2075113318010100 SN - 2075-1133 VL - 9 IS - 1 SP - 57 EP - 65 PB - Pleiades Publishing, Ltd. AN - OPUS4-43990 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Agea Blanco, Boris A1 - Meyer, Christian A1 - Müller, Ralf A1 - Günster, Jens T1 - Sand erosion of solar glass: Specific energy uptake, total transmittance, and module efficiency N2 - Surface roughness, R Z , normal transmittance, Τ N , total transmittance, Τ T , and photovoltaic (PV) module efficiency, η S , were measured for commercial solar glass plates and PV test modules identically sandblasted with different loads of quartz sand (200 – 400 μ m), impact inclination angles, and sand particle speed. Measured data are presented versus the specific energy uptake during sand blasting, E (J/m2). Cracks, adhering particles, and scratch ‐ like textures probably caused by plastic flow phenomena could be observed after sand blasting. Their characteristic size was much smaller than that of sand particles. After blasting and subsequent cleaning, the glass surface was still covered with adhering glass particles. These particles, cracks, and scratch ‐ like textures could not be removed by cleaning. For sand blasting with α = 30° inclination angle and E = 30 000 J/m2, normal transmittance, total transmittance, and relative module efficiency decreased by 29%, 2% and ∽ 2%, respectively. This finding indicates that diffusive transmission of light substantially contributes to PV module efficiency and that the module efficiency decrease caused by sand erosion can be better estimated from total than by normal transmittance measurements. KW - Transmittance KW - Efficiency KW - Photovoltaic modules KW - Roughness KW - Sand blasting PY - 2018 DO - https://doi.org/10.1002/er.3930 SN - 1099-114X SN - 0363-907X VL - 42 IS - 3 SP - 1298 EP - 1307 PB - Wiley & Sons, Ltd. AN - OPUS4-44157 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rockenhäuser, Christian A1 - Schriever, Sina A1 - von Hartrott, P. A1 - Piesker, Benjamin A1 - Skrotzki, Birgit T1 - Comparison of long-term radii evolution of the S-phase in aluminum alloy 2618A during ageing and creep N2 - A study was made on the effect of creep loading on the precipitate radii evolution of the aluminum alloy 2618A. The overageing process of the alloy was investigated under load at a temperature of 190 °C with stresses between 79 and 181 MPa and compared to stress free isothermal ageing. The precipitates responsible for strength were characterized using dark-field transmission electron microscopy (DFTEM). This allows the experimental Determination of radii distributions of the rod-shaped Al2CuMg precipitates and the evaluation regarding their mean precipitate radius. It was found that the mean precipitate radius enables the comparison of the different microstructural conditions of crept and uncrept samples. The mean precipitate radii of the samples experiencing creep are significantly higher than those of undeformed samples. It was shown that the acquired radii distributions are viable to determine averaged particle radii for comparison of the aged samples. A ripening process including pipe diffusion along dislocations describes the data on coarsening very well for the creep samples. KW - Aluminum alloys KW - Electron microscopy KW - Aging KW - Creep KW - Microstructure KW - S-Phase PY - 2018 DO - https://doi.org/10.1016/j.msea.2018.01.033 SN - 0921-5093 VL - 716 SP - 78 EP - 86 PB - Elsevier B. V. AN - OPUS4-44090 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 - Bruno, Giovanni A1 - Thiede, Tobias A1 - Mishurova, Tatiana A1 - Kromm, Arne A1 - Nadammal, Naresh A1 - Bode, Johannes A1 - Cabeza, Sandra T1 - Influence of deposition hatch length on residual stress in selective laser melted Inconel 718 N2 - The present study aims to evaluate the bulk residual stresses in SLM parts by using neutron diffraction measurements performed at E3 line -BER II neutron reactor- of Helmholtz-Zentrum für Materialien und Energie (HZB) Berlin. Together with microstructure characterization and distortion measurements, it is possible to describe the stress state throughout the whole sample. The sample was measured in as-build condition (on a build plate) and after releasing from the build plate. The used material is the nickel based superalloy 718. This alloy is widely used in aerospace and chemical industries due to its superior corrosion and heat resistant properties. Obtained results indicated different residual stress states for each of the transversal, longitudinal and normal component. The normal and transversal component exhibits a rather compressive behavior while the longitudinal was tensile in the center part of the sample and became compressive towards the tip. As expected, the absolute values of all stress components decreased after releasing the sample from the building plate. A surface scan utilizing a coordinate-measuring machine (CMM) allowed us to present top surface distortion before and after releasing. The top surface showed a distortion around ±80µm after releasing. Microstructure evolution in the scanning-building cross-section is largely dominated by columnar grains. In addition, many small random orientated grains are prominent in the regions of a laser overlap during SLM. In summary, for the sample of superalloy 718 manufactured by SLM, a small distortion occurred when removing the sample from the build plate whereby the residual stress state decreases. Moreover, the observed columnar grains in the building direction could give a reason for the lowest stress values in that normal direction. However, the most important parameter controlling the residual stresses is the temperature gradient. Hence, future investigations are planned for a different scan strategy to distribute the laser impact in a more homogenous manner. T2 - WAM2018 CY - Grenoble, France DA - 09.04.2018 KW - Additive manufacturing KW - SLM KW - Residual stress KW - In718 PY - 2018 AN - OPUS4-44694 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 - TY - CONF A1 - Blaeß, Carsten A1 - Müller, Ralf A1 - Feldmann, Ines A1 - Brauer, D.S. T1 - Sintering ability of fluoride-containing bioactive glass powder N2 - 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. T2 - 92. Glastechnische Tagung CY - Bayreuth, Germany DA - 28.05.2018 KW - Sintering KW - Bioactive glass KW - Crystallization PY - 2018 AN - OPUS4-45568 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Behrens, H. A1 - Bauer, U. A1 - Reinsch, Stefan A1 - Kiefer, P. A1 - Müller, Ralf A1 - Deubener, J. T1 - Structural relaxation mechanisms in hydrous sodium borosilicate glasses N2 - 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. KW - Borosilicate glass KW - Water KW - Relaxation KW - Internal friction KW - Glass transition PY - 2018 DO - https://doi.org/10.1016/j.jnoncrysol.2018.05.025 VL - 497 SP - 30 EP - 39 PB - Elsevier B.V. AN - OPUS4-45608 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Viguier, B. A1 - Poquillon, D. A1 - Ruffini, A. A1 - Le Bouar, Y. A1 - Finel, A. A1 - Fedelich, Bernard A1 - Feldmann, Titus A1 - Ijaz, M. T1 - Etude expérimentale des mécanismes de fermeture des pores par CIC dans un superalliage monocristallin CMSX4 N2 - Data about the creep behaviour of metals and their alloys at temperatures close to the melting point are very limited. The reason is that most engineering alloys are used at temperatures below 0.6-0.8 of their melting point, so, investigation of creep at higher temperatures has no practical relevance. For some special applications however it is important, in our case hot isostatic pressing (HIP) of singlecrystal turbine blades cast from nickel-base superalloys. In order to remove porosity the blades are HIPed at temperatures between -solvus and solidus where superalloy has no strengthening -phase and therefore is very soft. For example, the company Howmet Castings HIPs the superalloy CMSX-4 at the temperature 1288°C, which corresponds to a homologous temperature of about 0.97=1561 K/1612 K (solidus temperature). Knowledge about the creep behaviour of CMSX-4 at this temperature and understanding of the creep mechanisms are necessary to model the kinetics of pore closure during HIPing as well as to plan the parameters of the HIP process. N2 - Les aubes de turbines à gaz utilisées en particulier pour les turboréacteurs de l’aéronautique sont élaborées par fonderie en superalliage monocristallin à base de nickel. Le procédé de fonderie, ainsi que les traitements thermique d’homogénéisation réalisés à très haute température, induisent la présence de pores au sein des pièces qui affectent les propriétés mécaniques et la durée de vie des aubes. Afin de réduire cette porosité les motoristes effectuent un traitement de compression isostatique à chaud (CIC) au cours duquel la porosité diminue par fermeture des pores. Afin de mieux comprendre les mécanismes impliqués au cours du traitement de CIC, nous avons lancé un programme de recherche dans le cadre du projet ERA-Net MICROPORE. La modélisation par champ de phase des mécanismes en jeu est présentée au cours de ce colloque. Nous présentons dans cette affiche un des volets de la caractérisation expérimentale du projet. Des échantillons de superalliage CMSX4 sont observés après traitement de mise en solution et CIC sous 103 MPa à 1288°C pour différentes durées. Les pores présents sont caractérisés par microscopie électronique à balayage (MEB) afin de suivre l’évolution du taux de porosité au cours du traitement. Une caractérisation plus détaillée de pores partiellement refermés est menée par MEB et grâce à la diffraction des électrons rétrodiffusés (EBSD). Une vision tridimensionnelle de ces défauts est obtenue par des coupes métallographiques effectuées par découpe ionique (FIB). Le projet ERA – Net MICROPORE est financé en Allemagne par la DFG (projects EP 136/1-1 and FE933/2-1) et en France par l’ANR (projects ANR15-MERA-000-03 and ANR15-MERA-0003-04). T2 - Plasticité 2018 CY - Nancy, France DA - 09.04.2018 KW - Creep KW - CMSX4 KW - Superalloy KW - Dislocations PY - 2018 AN - OPUS4-44827 LA - fra AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nadammal, Naresh A1 - Kailas, Satish A1 - Szpunar, Jerzy A1 - Suwas, Satyam T1 - Development of microstructure and texture during single and multiple pass friction stir processing of a strain hardenable aluminium alloy N2 - 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. KW - Friction stir processing KW - Aluminium alloys KW - Electron back-scattered diffraction KW - Crystallographic texture KW - Dynamic recrystallization PY - 2018 UR - https://www.sciencedirect.com/science/article/pii/S1044580317336136 DO - https://doi.org/10.1016/j.matchar.2018.03.044 SN - 1044-5803 SN - 1873-4189 VL - 140 SP - 134 EP - 146 PB - Elsevier B.V CY - Amsterdam, The Netherlands AN - OPUS4-45125 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kaiser, T. M. A1 - Braune, C. A1 - Kalinka, Gerhard A1 - Schulz-Kornas, E. T1 - Nano-indentation of native phytoliths and dental tissues: implications for herbivore-plant combat and dental wear proxies N2 - 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. KW - Phytolith KW - Indentation hardness KW - Enamel KW - Dentine KW - Tooth wear PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-451417 UR - http://zoobank.org/5C7DBB2B-B27D-4CE6-9656-33C4A0DA0F39 DO - https://doi.org/10.3897/evolsyst.2.22678 VL - 2 SP - 55 EP - 63 PB - PENSOFT CY - USA AN - OPUS4-45141 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kuchenbecker, Petra A1 - Hodoroaba, Vasile-Dan A1 - Lindemann, Franziska A1 - Gemeinert, Marion A1 - Wohlleben, W. T1 - Advanced screening method using volume-specific surface area (VSSA) for nanomaterial classification of powders N2 - 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. T2 - Jahrestagung der Deutschen Keramischen Gesellschaft mit Symposium Hochleistungskeramik CY - München, Germany DA - 10.04.2018 KW - VSSA KW - Nanoparticles PY - 2018 AN - OPUS4-45097 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kuchenbecker, Petra T1 - Bestimmung der Partikelgrößenverteilung mittels Zentrifugen-Sedimentationsverfahren nach ISO 13318-2 (Küvette) N2 - 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. T2 - Rheologie und Stabilität von dispersen Systemen CY - Potsdam, Germany DA - 14.04.2018 KW - Partikelgrößenverteilung KW - Analytische Zentrifuge PY - 2018 AN - OPUS4-45098 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kuchenbecker, Petra A1 - Hodoroaba, Vasile-Dan A1 - Lindemann, Franziska A1 - Wohlleben, W. T1 - Advanced screening method using volume-specific surface area (VSSA) for nanomaterial identification of powders N2 - 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. T2 - Workshop on Reference Nanomaterials CY - Berlin, Germany DA - 14.05.2018 KW - VSSA KW - Nanomaterial screening KW - Nano-powder characterization PY - 2018 AN - OPUS4-45099 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mishurova, Tatiana A1 - Cabeza, Sandra A1 - Thiede, Tobias A1 - Nadammal, Naresh A1 - Kromm, Arne A1 - Klaus, Manuela A1 - Genzel, Christoph A1 - Haberland, Christoph A1 - Bruno, Giovanni T1 - The influence of the support structure on residual stress and distortion in SLM Inconel 718 parts N2 - 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. KW - Additive manufacturing KW - SLM KW - Residual stress KW - Synchrotron X-ray diffraction KW - IN718 PY - 2018 DO - https://doi.org/10.1007/s11661-018-4653-9 SN - 1073-5623 VL - 49A IS - 7 SP - 3038 EP - 3046 PB - Springer Sciences & Business Media CY - New York, NY AN - OPUS4-45100 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Elsayed, H. A1 - Zocca, Andrea A1 - Schmidt, J. A1 - Günster, Jens A1 - Colombo, P. A1 - Bernardo, E. T1 - Bioactive glass-ceramic scaffolds by additive manufacturing and sinter-crystallization of fi ne glass powders N2 - 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. KW - 3D-Printing KW - Bio Ceramic KW - Additive manufacturing PY - 2018 DO - https://doi.org/10.1557/jmr.2018.120 SN - 2044-5326 SN - 0884-2914 VL - 33 IS - 14 SP - 1960 EP - 1971 PB - Cambridge University Press AN - OPUS4-45718 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Günster, Jens A1 - Zocca, Andrea A1 - Lima, Pedro A1 - Acchar, W. T1 - 3D printing of porcelain by layerwise slurry deposition N2 - 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. KW - Binder jetting KW - Additive Manufacturing KW - 3D printing KW - Porcelain PY - 2018 DO - https://doi.org/10.1016/j.jeurceramsoc.2018.03.014 SN - 0955-2219 VL - 38 IS - 9 SP - 3395 EP - 3400 PB - Elsevier Ltd. AN - OPUS4-45713 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Chi, Jinchun A1 - Zocca, Andrea A1 - Agea Blanco, Boris A1 - Melcher, J. A1 - Sparenberg, M. A1 - Günster, Jens T1 - 3D Printing of Self-Organizing Structural Elements for Advanced Functional Structures N2 - 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. KW - Additive Manufacturing KW - Self-Assembly KW - 3D-Printing KW - Polymeric Materials PY - 2018 DO - https://doi.org/10.1002/admt.201800003 SN - 2365-709X VL - 3 IS - 5 SP - 1800003-1 EP - 1800003-7 PB - Wiley-VCH CY - Weinheim AN - OPUS4-45714 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bernardino, R. A1 - Wirth, C. A1 - Stares, S.L. A1 - Salmoria, G.V. A1 - Hotza, D. A1 - Günster, Jens T1 - Manufacturing of SiO2-Coated b-TCP Structures by 3D Printing using a Preceramic Polymer as Printing Binder and Silica Source N2 - 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. KW - Tricalcium Phosphate KW - 3D-Printing KW - Preceramic polymer KW - Bone regeneration PY - 2018 DO - https://doi.org/10.4416/JCST2017-00056 VL - 9 IS - 1 SP - 37 EP - 41 PB - Göller Verlag CY - 76532 Baden-Baden AN - OPUS4-45715 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ghafafian, Carineh A1 - Popiela, Bartosz A1 - Trappe, Volker T1 - Damage Mechanisms of Scarf Joint Repairs for Wind Turbine Rotor Blade Shell Applications N2 - Wind turbine rotor blades, made of fiber reinforced polymers (FRP), often fail before their projected 20-year lifespan, largely due to defects that originate during manufacturing and are propagated by operational fatigue and environmental conditions. The cost-intensive replacement outcomes lead to a high loss of earnings, and are one of the inhibitors of wind turbine production [1]. A potential repair alternative is to locally patch these areas of the blades with adhesively bonded structural repairs. However, the effects of such repair methods of the outer shell region on the structural integrity of the rotor blades are still largely unknown, and are thus investigated in this project. The shell components of rotor blades are made of FRP composite material sandwiching a lightweight core, often a rigid foam or Balsa wood. The repair methods involve replacing the lost load path with a new material that is joined to the parent structure [2]. Repairs in this project focus on the scarf method, which allow for a smoother load distribution across the joint, aiming to study the damage mechanism of glass FRP scarf repairs for wind turbine blade shell applications. Namely, the source and path of the damage initiation and propagation, role of the interface between parent and patch material, and the role of the fiber orientation mismatch at this interface are examined. Biaxial ±45° and 0/90° FRP specimens are produced with the vacuum-assisted resin infusion (VARI) process using E-glass non-crimp fabric. The patch layers are then joined using VARI with a scarf ratio of 1:50, using glass FRP fabric with half the areal weight of the parent side to allow for better drapability. The methods and practices in specimen production are based on common industry practice in rotor blade shell manufacturing and repairs. The specimens are tested under uniaxial tensile load, during which they are periodically monitored for damage onset. A comparison of the ±45° and 0/90° specimens allows for an understanding of the role of a highly mismatching fiber orientation in the transition zone between parent and patch material on the failure mechanism of the scarf joint. Although failure in both orientations begins as delamination at the joint edge, the difference in the mechanisms at play in the two different specimen types leads ultimately to different fracture paths. Namely, in the inter fiber failure mechanism of the ±45° specimens, the higher interlaminar strength compared to the intralaminar strength of the laminate leads to intralaminar failure of the ±45° scarf joint specimens. Alternatively, the competition in the 0/90° specimens lies between the interlaminar strength and fiber failure strength, and here we experience failure primarily across the scarf joint length. The scarf joint in the 0/90° specimens disrupts the continuity of the load-carrying 0° layers, directing the failure path to remain primarily along the scarf joint. Experimental results are compared to finite element analyses of scarf patch repairs on glass FRP sandwich specimens with the same respective layup orientations, where the damage initiation regions are identified and correlated to fiber orientation, serving as a bridge to future work which will experimentally examine the scarf repair patches on sandwich shell specimens. T2 - Joint Event: ICCS23 - 23rd International Conference on Composite Structures & MECHCOMP6 - 6th International Conference on Mechanics of Composites CY - Online meeting DA - 01.09.2020 KW - Wind turbine blade shells KW - Glass fiber reinforced polymers KW - Scarf repairs PY - 2020 AN - OPUS4-51175 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lüders, C. A1 - Kalinka, Gerhard A1 - Li, Wei A1 - Sinapius, M. A1 - Wille, T. T1 - Experimental and numerical multiscale approach to thermally cycled FRP N2 - Due to the different thermal expansion of the constituent materials, cyclic thermal loading of FRP induces alternating stresses in the material at two scales: at the micro scale (level of fibre–matrix-interaction) and at the macro scale (level of the multidirectional laminate). Especially the micro scale effect is not comprehensively investigated yet. Additionally, computational investigations mostly neglect this effect due to the homogenous modelling of the composite material. As this effect is assumed to significantly contribute to the fatigue of FRP at thermal loads, the present paper suggests an experimental and numerical multiscale approach including Experiments at the different involved material scales to separately observe the effects acting at these scales. The approach also includes numerical modelling for each scale to complement the knowledge gained from the Experiments and to create a basis for the consideration of the micro effect even in macroscopic fatigue models treating homogeneous modelled composites. The main focus of the contribution is to bring the overall Approach up for discussion, rather than to present the multiscale modelling details. KW - Fatigue KW - Thermal cycling KW - Fibre reinforced plastic KW - Cryogenic KW - Carbon Fibre KW - Epoxy Resin PY - 2020 DO - https://doi.org/10.1016/j.compstruct.2020.112303 SN - 0263-8223 VL - 244 SP - 112303 PB - Elsevier Ltd. CY - Niederlande AN - OPUS4-50844 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Waurischk, Tina A1 - Thieme, C. A1 - Rüssel, C. T1 - Crystal growth velocities of a highly anisotropic phase obtained via surface and volume crystallization of barium–strontium–zinc silicate glasses N2 - In the past few years, a new phase, Ba0.5Sr0.5Zn2Si2O7 with negative thermal expansion has been described in the literature. Some excess of SiO2 is necessary to produce glasses from which the Ba0.5Sr0.5Zn2Si2O7 phase can be crystallized. Unfortunately, in such glasses usually surface crystallization occurs; however, the addition of nucleating agents such as trace quantities of platinum or relatively high quantities of ZrO2 is necessary to achieve bulk nucleation. These additional components also affect the crystal growth velocity, which furthermore is different for crystal growth from the surface and in the bulk. In this paper, three different chemical compositions containing different ZrO2 concentrations, where one composition additionally contains 100 ppm platinum, are studied with respect to their crystallization behaviour. Although the compositions do not differ much, the crystallization behaviour and also the Crystal growth velocities are surprisingly different. KW - Glass ceramic KW - Crystal growth velocity KW - Low expansion PY - 2020 DO - https://doi.org/10.1007/s10853-020-04773-6 SN - 0022-2461 VL - 55 SP - 10364 EP - 10374 PB - Springer AN - OPUS4-50853 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Waurischk, Tina A1 - Müller, Ralf A1 - Reinsch, Stefan A1 - Kiefer, P. A1 - Deubener, J. A1 - Balzer, R. A1 - Behrens, H. T1 - Crack Growth in Hydrous Soda-Lime Silicate Glass N2 - Stable crack growth was measured for nominal dry and water-bearing (6 wt%) soda-lime silicate glasses in double cantilever beam geometry and combined with DMA studies on the effects of dissolved water on internal friction and glass transition, respectively. In vacuum, a decreased slope of logarithmic crack growth velocity versus stress intensity factor is evident for the hydrous glass in line with an increase of b-relaxation intensity indicating more energy Dissipation during fracture. Further, inert crack growth in hydrous glass is found to be divided into sections of different slope, which indicates different water related crack propagation mechanism. In ambient air, a largely extended region II is observed for the hydrous glass, which indicates that crack growth is more sensitive to ambient water. KW - Internal friction KW - Soda-lime silicate glass KW - Water content KW - Stable crack growth KW - DCB geometry KW - Stress intensity factor PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506829 DO - https://doi.org/10.3389/fmats.2020.00066 VL - 7 SP - Articel 66 AN - OPUS4-50682 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Chinellato, Fabio A1 - Wilbig, Janka A1 - Al-Sabbagh, Dominik A1 - Colombo, P. A1 - Günster, Jens T1 - Gas flow assisted powder deposition for enhanced flowability of fine powders: 3D printing of alpha-tricalcium phosphate N2 - The possibility of creating patient-specific individual implants makes Additive Manufacturing technologies of special interest for the medical sector. For substitution of bone defects, powder based Additive Manufacturing by Binder Jetting is a suitable method to produce complex scaffold-like structures made of bioceramics with easily adapted geometries and controlled porosity. The process inherent residual porosity in the printed part, even though desired as it supports bone ingrowth, also leads to limited mechanical strength. Currently, bioceramic scaffolds made by Binder Jetting feature suitable biocompatible and biodegradable properties, while a sufficient mechanical stability is rather challenging. The purpose of this work is to apply the gas flow assisted powder deposition introduced in 2014 by Zocca et al., to the powder bed during printing of bioceramic tablets and scaffolds using α-TCP powder as feedstock. This enables exploiting the advantages of an increased powder bed density, thereby improving the mechanical properties of the printed parts. KW - Additive Manufacturing KW - Binder Jetting KW - Gas flow assisted powder deposition KW - Alpha-tricalcium phosphate KW - Scaffold PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510138 DO - https://doi.org/10.1016/j.oceram.2020.100003 SN - 2666-5395 VL - 1 SP - 100003 PB - Elsevier Ltd. AN - OPUS4-51013 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Erdmann, Maren A1 - Kleinbub, Sherin A1 - Wachtendorf, Volker A1 - Schütter, Jan David A1 - Niebergall, Ute A1 - Böhning, Martin A1 - Koerdt, Andrea T1 - Photo-oxidation of PE-HD affecting polymer/fuel interaction and bacterial attachment N2 - In the present study, a simple approach was used to investigate the effect of UV-exposure on two high density Polyethylene materials (PE-HD), commonly used for storage tanks, on fuel sorption behavior and colonization by microorganisms. The aim was to investigate whether the sorption behavior of the fuels (diesel/biodiesel) and the colonization by microorganisms, frequently occurring in the fuel, is affected and may lead to undesirable or safety-relevant material changes. We showed that the UV-irradiation leads to significant changes of the sorption behavior due to chemi-crystallization and crosslinking. The fuel Sorption is affected by the UV-induced formation of polar carbonyl and hydroxyl groups predominantly occurring at the surface. With respect to microbial colonization behavior for Bacillus subtilis and Pseudomonas aeruginosa, isolated from a contaminated diesel sample, differences of the initial adhesion could be shown depending on the initial type of polyethylene as well as on the degree of UV-induced degradation. KW - High density polyethylene KW - Bacterial attachment KW - UV-irradiation KW - Fuel sorption PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510001 DO - https://doi.org/10.1038/s41529-020-0122-1 VL - 4 IS - 1 SP - Article number: 18 PB - Nature Partner Journals AN - OPUS4-51000 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - de Melo Bernardino, Raphael A1 - Valentino, S. A1 - Franchin, G. A1 - Günster, Jens A1 - Zocca, Andrea T1 - Manufacturing of ceramic components with internal channels by a novel additive/subtractive hybridizazion process N2 - A new approach for fabrication of ceramic components with inner channels is proposed, as a result of the combination of two additive and one subtractive manufacturing processes. In this project, porcelain parts are manufactured by the Layerwise Slurry Deposition (LSD) process, meanwhile end milling and Direct Ink Writing (DIW) are applied to create channels on the surface of the deposited ceramic. Unique to the LSD process is the Formation of a freestanding powder bed with a mechanical strength comparable to conventional slip casted ceramic green bodies. Combining these three processes allows the manufacturing of ceramic objects containing an internal path of ink, which in this case was a graphite-based ink that can be further eliminated by heat treatment to obtain a porcelain object embedded with channels. The results show the capabilities of this method and its potential to fabricate not only parts with inner channels, but also multi-material and multi-functional components (such as integrated electronic circuits). KW - Additive Manufacturing KW - Layerwise Slurry Deposition KW - Hybrid Manufacturing PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510012 UR - https://www.sciencedirect.com/science/article/pii/S2666539520300109?via%3Dihub DO - https://doi.org/10.1016/j.oceram.2020.100010 VL - 2 SP - 100010 PB - Elsevier Ltd. AN - OPUS4-51001 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zocca, Andrea A1 - Fateri, M. A1 - Al-Sabbagh, Dominik A1 - Günster, Jens T1 - Investigation of the sintering and melting of JSC-2A lunar regolith simulant N2 - Future lunar exploration can benefit greatly from In-Situ Resource Utilization. Accordingly, the in-Situ Resource Utilization approach highlights the need for detailed analysis of lunar regolith. In this study, JSC-2A Simulant was studied regarding its sintering and melting behaviour using Differential Thermal Analysis under ambient and inert conditions. The minerals at the crystalline peaks were determined using X-Ray Diffraction analysis. Moreover, melting droplet shape and wetting behaviour of pressed regolith samples of different particle size distributions were studied by Hot Stage Microscopy technique. Hot Stage Microscopy experiments were performed at different heating rates under ambient conditions. Bloating effects within the solidified samples were then qualitatively examined by X-ray tomography. Lastly, the optimization of processing strategies for the Additive Manufacturing of lunar regolith is discussed. KW - Lunar regolith KW - Sintering KW - Melting KW - Hot stage microscopy PY - 2020 DO - https://doi.org/10.1016/j.ceramint.2020.02.212 VL - 46 IS - 9 SP - 14097 EP - 14104 PB - Elsevier Ltd. AN - OPUS4-50869 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Karl, D. A1 - Duminy, T. A1 - Lima, P. A1 - Kamutzki, F. A1 - Gili, A. A1 - Zocca, Andrea A1 - Günster, Jens A1 - Gurlo, A. T1 - Clay in situ resource utilization with Mars global simulant slurries for additive manufacturing and traditional shaping of unfired green bodies N2 - The wet processing of regolith simulant for clay in situ resource utilization (ISRU) on Mars is presented. The two raw materials from the Mars global simulant family, one without clay (MGS-1) and one with clay - sodium montmorillonite smectite - (MGS-1C) were milled and mixed to produce a simulant with small particle size and reduced clay content (MGS-1C/8). All three simulants and the pure clay raw material were extensively characterized using XRF, synchrotron XRD, gas adsorption and gas pycnometry methods. In a straightforward processing approach, MGS-1C/8 was mixed with water and different dispersant approaches were investigated, all of which gave stable slurries. Particle size distribution, rheology, ion concentration, pH and electrical conductivity of these slurries were characterized. The slurry systems can easily be adapted to fit all typical ceramic shaping routes and here parts of varying complexity from slip casting, throwing on a potter's wheel and additive manufacturing, including material extrusion (robocasting) and binder jetting (powder bed 3D printing) were produced. The unique properties of the sodium montmorillonite clay, which is readily accessible in conjunction with magnesium sulfate on the Martian surface, acted as a natural nanosized binder and produced high strength green bodies (unfired ceramic body) with compressive strength from 3.3 to 7.5 MPa. The most elaborate additive manufacturing technique layerwise slurry deposition (LSD) produced water-resistant green bodies with a compressive strength of 30.8 ± 2.5 MPa by employing a polymeric binder, which is similar or higher than the strength of standard concrete. The unfired green bodies show sufficient strength to be used for remote Habitat building on Mars using additive manufacturing without humans being present. KW - Mars KW - Smectite KW - Clay ISRU KW - MGS-1 regolith simulant KW - 3D printing KW - Additive manufacturing PY - 2020 DO - https://doi.org/10.1016/j.actaastro.2020.04.064 VL - 174 SP - 241 EP - 253 PB - Elsevier Ltd. AN - OPUS4-50870 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Gibson, N. A1 - Kuchenbecker, Petra A1 - Rasmussen, K. A1 - Hodoroaba, Vasile-Dan A1 - Rauscher, H. ED - Hodoroaba, Vasile-Dan ED - Unger, Wolfgang ED - Shard, A.G. T1 - Volume-specific surface area by gas adsorption analysis with the BET method N2 - This chapter first gives an introduction to the concepts of SSA and volume-specific surface area (VSSA) and an outline of the BET method. It continues with a discussion of the relationship between particle size, shape, and the VSSA, followed by an overview of instrumentation, experimental methods, and standards. Finally, sections on the use of the VSSA as a tool to identify nanomaterials and non-nanomaterials and its role in a regulatory context provide some insight on the importance of VSSA in the current Regulation of nanomaterials. KW - Nanomaterials KW - Volume specific surface area PY - 2020 SN - 978-0-12-814182-3 DO - https://doi.org/10.1016/B978-0-12-814182-3.00017-1 SP - 265 EP - 293 PB - Elsevier CY - Amsterdam AN - OPUS4-49572 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Rabe, Torsten A1 - Schulz, Bärbel A1 - Salehi, M. T1 - Alterungsbeständige keramische Federsensoren durch nanostrukturierte Werkstoffe, Präzisionsbearbeitung und hochdielektrische Nanosuspensionen N2 - Das Ziel des Gesamtvorhabens bestand darin, einen neuartigen kapazitiven Sensortyp zur hochauflösenden Bestimmung von Masse- und Gravitationskraftänderungen zu entwickeln. Bisherige Technologien nutzten dafür Federn oder Biegebalken aus gehärteten metallischen Werkstoffen, deren Alterungsverhalten die Präzision der Kräftemessung begrenzen. Grundprinzip des neuen Sensortyps ist es, eine auf die keramische Feder einwirkenden Änderung der Gewichts- oder Gravitationskraft durch eine Erfassung der Kapazitätsänderung am Sensor zu bestimmen. Dazu muss die durch Stauchung oder Dehnung der Feder entstehende Kapazitätsänderung mit hoher Auflösung reproduzierbar gemessen werden. Neben einem geeigneten Sensordesign waren Lösungen für Messsignalerfassung und -auswertung (Elektronik/Software) und die Systemintegration zu entwickeln. Die wichtigsten im Rahmen des BAM-Teilvorhabens erzielten Ergebnisse sind: - Ausgehend von kommerziellen High-end Keramikpulvern wurden durch Optimierung der keramischen Technologie nahezu porenfreie Al2O3, ZrO2 und Si3N4-Werkstoffe hergestellt und bezüglich Gefüge und Phasenbestand sowie mechanischen, thermischen und elektrischen Eigenschaften bewertet. Insbesondere die defektfreie Herstellung von nanostrukturierten Werkstoffen erforderte umfangreiche Variationen der Prozessparameter. Geeignete Werkstoffvarianten wurden für die Federherstellung ausgewählt. - Gemeinsam mit den Projektpartnern wurden Layoutvarianten für Schraubendruckfedern mit rechteckigem Windungsquerschnitt und für die Federeinbindung in das Sensorsystem erarbeitet. - 4 Federvarianten wurden an der BAM durch Hartbearbeitung von gesinterten Hohlzylindern umgesetzt. Fertigungstoleranzen von < ±10 µm für Windungsbreite, Windungshöhe und Windungsabstand und dünnfilm-kompatible innere Windungsflächen (Ra < 0,2 µm) wurden erreicht. Al2O3- und ZrO2-Federn können rissfrei und mit sehr guter Kantenqualität gefertigt werden, bei Si3N4-Federn konnten Kantenschädigungen nicht vollständig verhindert werden. - Mit der entwickelten Herstellungstechnologie können sowohl „harte“ als auch sehr „weiche“ Federn produziert werden. Federkonstanten zwischen 0,02 N/mm und 10 N/mm wurden realisiert. Die Reproduzierbarkeit der Federfertigung ist gegeben, innerhalb einer Charge unterschieden sich die Federkonstanten der gefertigten Federn nur um etwa +/- 1%. - An einem speziell entwickelten Versuchsstand wurden die Federn unter zyklischer Druckbelastung im Temperaturbereich von -20 bis +80 °C untersucht. An den Al2O3- und ZrO2-Federn wurden keine Schädigungen beobachtet, die Federkonstante wird durch die zyklische Langzeitbelastung nicht verändert. - Die Eignung der keramischen Federn für den Applikationsfall wurde mit zahlreichen Spannungs-Dehnungs-Experimenten, teilweise an speziell aufgebauten Versuchsapparaturen, untersucht. An Al2O3- und Si3N4-Federn wurde – wie erwartet – gefunden, dass die Federkonstante unabhängig von der Belastungsgeschwindigkeit ist und unter konstanter Last auch über lange Zeiträume keine Verformung auftritt. Überraschenderweise zeigten ZrO2 (TZP)-Federn ein zeitabhängiges Verhalten unter Last. Dieses ist besonders stark bei Y-stabilisierten Werkstoffvarianten ausgebildet, wurde aber mit Hochpräzisionsmessungen auch bei Ce-stabilsierten Werkstoffen nachgewiesen. Die Deformation ist reversibel, eine vollständige Relaxation wird erst nach Tagen erreicht. Aufgrund der zeitabhängigen Verformung können ZrO2 (TZP)-Federn, trotz ihrer hervorragenden Festigkeit und Bruchzähigkeit, nicht für die konzipierten Sensorfedern eingesetzt werden. - Das durch die Fa. Siegert TFT entwickelte Metallisierungs-Schichtsystem, bestehend aus aufgesputterten Ti-, Pt- und Au-Schichten verstärkt durch eine galvanisch aufgebrachte Au-Schicht, wurde an der BAM umfassend bewertet. Die Schichten sind untereinander und mit der Keramik weitgehend defektfrei verbunden, die lokale Schichtdicke schwankt jedoch bedingt durch Abschattungseffekte während der Beschichtungsvorgang. Es wurden Schichtwiderstände zwischen 50 und 90 Ohm und damit die Zielvorgabe des Projektes (< 100 Ohm) erreicht. In statischen und dynamischen Belastungstests wurden keine Veränderungen der Leitungswiderstände festgestellt. - Zur Erhöhung der Kapazität des Kondensators kann der Raum zwischen den Federwindungen statt mit Luft mit einer Flüssigkeit mit hoher Dielektrizitätskonstante gefüllt werden. Als geeignete Flüssigkeit wurde Propylencarbonat mit einer Dielektrizitätskonstante von 65, einem hohen Siedepunkt und einer geringen Viskosität identifiziert. Um eine noch höhere Dielektrizitätskonstante zwischen den Federwindungen zu erreichen. wurden Suspensionen aus Silikonöl und nanokristallinem Bariumtitanat hergestellt und bezüglich ihrer Langzeitstabiltät charakterisiert. - Gemäß den Anforderungen des Projektpartners KOMPASS wurden maßgeschneiderte Al2O3-Federn mit einer Federkonstante < 0,1 N/mm hergestellt und für den Aufbau des finalen Demonstrator eingesetzt. Die prinzipielle Funktionsfähigkeit des neuen Sensorkonzeptes auf Basis keramischer Federn wurde mit dem im Projekt aufgebauten Demonstrator nachgewiesen. Die Umsetzung der F+E-ergebnisse in eine industrielle Nutzung zur Herstellung von Gravimetern wird vom Projektpartner KOMPASS angestrebt und ist bereits mit detaillierten Zeitplänen untersetzt. KW - Langzeitstabilität KW - Sensorik KW - Keramikfeder KW - Spannungs-Dehnungs-Verhalten PY - 2019 UR - https://www.gbv.de/dms/tib-ub-hannover/1681417375.pdf UR - https://www.tib.eu/de/suchen/id/TIBKAT%3A1681417375/Alterungsbest%C3%A4ndige-keramische-Federsensoren-durch/ SP - 1 EP - 64 PB - Bundesanstalt für Materialforschung und -prüfung CY - Berlin AN - OPUS4-50742 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Matz, R. A1 - Rabe, Torsten A1 - Töpfer, J. A1 - Ziesche, S. T1 - Circuit-Board-Integrated Transformers Design and Manufacture N2 - Transformers couple two sections of a circuit by electromagnetic induction. They are widely used to either transform alternating voltage levels or to transmit power or signals across galvanic isolation. Both of these functions are essential for the operation of sensors and controllers. Covering all aspects from idea to circuit performance and from design to manufacture, this paper presents the first comprehensive description of the making of miniaturized, rugged, up-to-100W transformers for embedding into multilayer circuit boards. For circular coils, the well-manageable Ampere-Laplace law is shown to yield reliable designs, predicting correctly the performance of manufactured hardware. This enables fast design without lengthy finite element modelling. In the low-power linear regime, basic relations describe how the device’s characteristics evolve from the material properties and device structure. While scattering Parameters are useful for the analysis of isolated transformers with their intrinsic parasitics, the interaction with the components of the final circuit and the aspects of power and efficiency are addressed by chain matrixes. While these design rules are similar for multilayer boards of different material (like epoxy, Teflon, ceramics), the manufacturing of ceramic board transformers is considered here in detail. Low-temperature-cofired ceramic (LTCC) boards being sintered at 900 °C are particularly suited for harsh environments with chemical or thermal stress as frequently found at sensor positions. The transformer performance usually benefits from or even requires an integrated ceramic core of higher permeability, a ferrite, to shape the magnetic flux. Methods to sinter ferrites inside a dielectric ceramic multilayerandto measure their performance are therefore described in detail.Asthe sintering behaviour of dielectricandmagnetic ceramics differs considerably, their simultaneous sintering is challenging.However, the sintering temperatures of the usefulMnZnand NiZnCu ferrites can be lowered to that of the dielectric material with only moderate loss of permeability by glass additives. Furthermore, thermal mismatch between materials causes catastrophic failure or at least stress and loss of magnetic performance during cooling to room temperature after sintering. This is avoidable by either adjusting the thermal expansion coefficient of the ferrite or by enclosing the ferrite between stressreleasing separation layers.We present the state of the art in materials development according to the first approach as well as fully functional devices made with the second technique. Other applications not directly addressed but well related to this work are characterized by low load resistance in relation to the coil resistance of the transformer. Efficient power transmission then requires that technological solutions are applied to achieve the lowest possible resistive loss inside the coils by an enlarged conductor cross-section. As this is particularly challenging for LTCC boards, a technique is discussed to fabricate conductor traces with a thickness larger than their width. KW - Multilayer ceramic technology KW - LTCC KW - Transformer PY - 2020 DO - https://doi.org/10.4416/JCST2019-00071 SN - 2190-9385 VL - 11 IS - 1 SP - 44 EP - 61 PB - Göller Verlag CY - Baden-Baden AN - OPUS4-50751 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Trappe, Volker A1 - Kremberg, Jan T1 - Betriebsfestigkeit von Struktur-Klebungen im Anwendungsgebiet der CS22 N2 - Moderne Segelflugzeuge sind voll-verklebte tragende FKV-Strukturen. Über die Schwingfestigkeit der Faser-Kunststoff-Verbunde (FKV) und die Lebensdauerabschätzung dieser Werkstoffklasse auf Basis verschiedener Lastspektren wurden insbesondere von Christoph Kensche verschiedenen Arbeiten durchgeführt und auch auf dem Symposium für Segelflugzeugentwicklung vorgestellt. Hingegen ist die Betriebsfestigkeit von Struktur-Klebungen im Anwendungsbereich der CS22 vergleichsweise wenig untersucht worden. Über die Jahre wurden in verschiedenen Projekten immer wieder Probleme in Struktur-Klebungen (u.a. Betriebsbelastungsversuche an Versuchs-Holmen) identifiziert, analysiert und spezielle Prüfverfahren weiter entwickelt (Projekt „Tragflügel neuer Technologie für die allgemeine Luftfahrt“, FK SIF765). Im Rahmen des LuFo-Vorhabens GeAviBoo (General Aviation Booster) wurde in zwei Arbeitspaketen das Thema erneut aufgegriffen und Betriebsbelastungsversuche an Klebproben durchgeführt. Im Rahmen des Vortrages werden die Erkenntnisse der letzten 10 Jahre aufbereitet und die neusten Ergebnisse vorgestellt. T2 - Symposium für Segelflugzeugentwicklung CY - Online meeting DA - 19.11.2020 KW - Polymer Matrix Composites KW - Betriebsfestigkeit KW - Klebung KW - General Aviation PY - 2020 AN - OPUS4-51861 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Trappe, Volker T1 - Composite materials - focus polymer matrix composites (PMC) N2 - Lecture about polymer matrix composites as part of the first trainings event GW4SHM, properties, production, basic theory, testing. T2 - 1. Training GW4SHM-Project CY - BAM, Berlin, Germany DA - 23.11.2020 KW - Polymer matrix composites KW - Composite testing KW - NDT PY - 2020 AN - OPUS4-51868 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ávila Calderón, Luis Alexander T1 - Mechanical behaviour of AM metals: Creep of LPBF 316L and low-cycle-fatigue of LMD Ti-6Al-4V N2 - Additively manufactured metallic materials have already started to find application in safety-relevant components. However, this has only happened for certain materials and specific applications and loading conditions, since there is still an extensive lack of knowledge as well as of historical data regarding their mechanical behaviour. This contribution aims to address this lack of understanding and historical data concerning the creep behaviour of the austenitic stainless steel 316L manufactured by Laser-Powder-Bed-Fusion (L-PBF) and the low-cycle-fatigue behaviour of the titanium alloy Ti-6Al-4V manufactured by Laser-Metal-Deposition (LMD). Furthermore, it aims to assess their mechanical behaviour against their conventional counterparts. With that in mind, specimens from conventional and additive materials are tested and their mechanical behaviour analysed based on characteristic curves. To understand the damage behaviours the materials are characterized by destructive and non-destructive techniques before and after failure. T2 - 1st Workshop on In-situ Monitoring and Microstructure Development in Additive Manufacturing CY - Online Meeting DA - 10.12.2020 KW - Ti-6Al-4V KW - 316L KW - Additive manufacturing KW - Creep behaviour KW - Low-cycle-fatigue behaviour PY - 2020 AN - OPUS4-51879 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fedelich, Bernard A1 - Feldmann, Titus A1 - Haftaoglu, Cetin A1 - Nolze, Gert A1 - Schriever, Sina A1 - Epishin, A. A1 - Camin, B. A1 - Lopez-Galilea, I. A1 - Ruttert, B. A1 - Theisen, W. T1 - Untersuchung des Kriechverhaltens einer Nickelbasis-Superlegierung bei ultrahohen homologen Temperaturen und Anwendung auf das heiß-isostatische Pressen (HIP) N2 - Mit Hilfe des HIP-Verfahrens („Hot Isostatic Pressing“) werden Poren in der einkristallinen Nickel-Basis Superlegierung CMSX-4 kontinuierlich geschrumpft und dadurch die nach der Erstarrung und der Wärmebehandlung vorhandene Porosität stark reduziert. In diesem Beitrag werden experimentelle und numerische Untersuchungen zu den Mechanismen der Porenschrumpfung zusammengefasst. Es zeigt sich, dass das Verformungsverhalten während Kriechversuchen bei der HIP-Temperatur durch Versetzungsgleitung auf oktaedrischen Ebenen dominiert wird. Dagegen zeigen Messungen der Porositätsabnahme und Simulationen des Porenschließens, dass die Kinetik der Porenschrumpfung durch das Phänomen der Leerstellendiffusion zwischen Poren und Kleinwinkelkorngrenzen („Low Angle Boundary“, LAB) bestimmt wird. Im Gegensatz führt die klassische Kristallviskoplastizität zu einer systematischen Überschätzung dieser Kinetik. Der scheinbare Widerspruch lässt sich auflösen, wenn man bedenkt, dass auf der Skala der Poren Versetzungsquellen nicht gleichmäßig verteilt sind, wie in der konventionellen Kristallplastizität implizit angenommen wird. Stattdessen wird in einem weiterführenden Modell davon ausgegangen, das Kleinwinkelkorngrenzen (LABs) als Versetzungsquellen fungieren, während die Scherspannungen sehr stark in der Nähe der Poren lokalisiert sind, was die Emission von Versetzungen deutlich reduziert. T2 - Langzeitverhalten warmfester Stähle und Hochtemperaturwerkstoffe CY - Online meeting DA - 27.11.2020 KW - HIP KW - Superlegierung KW - Kriechen PY - 2020 AN - OPUS4-51795 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fedelich, Bernard A1 - Feldmann, Titus A1 - Haftaoglu, Cetin A1 - Nolze, Gert A1 - Schriever, Sina A1 - Epishin, A. A1 - Camin, B. A1 - Lopez-Galilea, I. A1 - Ruttert, B. A1 - Theisen, W. T1 - Untersuchung des Kriechverhaltens einer Nickelbasis-Superlegierung bei ultrahohen homologen Temperaturen und Anwendung auf das heiß-isostatische Pressen (HIP) N2 - Mit Hilfe des HIP-Verfahrens („Hot Isostatic Pressing“) werden Poren in der einkristallinen Nickel-Basis Superlegierung CMSX-4 kontinuierlich geschrumpft und dadurch die nach der Erstarrung und der Wärmebehandlung vorhandene Porosität stark reduziert. In diesem Beitrag werden experimentelle und numerische Untersuchungen zu den Mechanismen der Porenschrumpfung zusammengefasst. Es zeigt sich, dass das Verformungsverhalten während Kriechversuchen bei der HIP-Temperatur durch Versetzungsgleitung auf oktaedrischen Ebenen dominiert wird. Dagegen zeigen Messungen der Porositätsabnahme und Simulationen des Porenschließens, dass die Kinetik der Porenschrumpfung durch das Phänomen der Leerstellendiffusion zwischen Poren und Kleinwinkelkorngrenzen („Low Angle Boundary“, LAB) bestimmt wird. Im Gegensatz führt die klassische Kristallviskoplastizität zu einer systematischen Überschätzung dieser Kinetik. Der scheinbare Widerspruch lässt sich auflösen, wenn man bedenkt, dass auf der Skala der Poren Versetzungsquellen nicht gleichmäßig verteilt sind, wie in der konventionellen Kristallplastizität implizit angenommen wird. Stattdessen wird in einem weiterführenden Modell davon ausgegangen, das Kleinwinkelkorngrenzen (LABs) als Versetzungsquellen fungieren, während die Scherspannungen sehr stark in der Nähe der Poren lokalisiert sind, was die Emission von Versetzungen deutlich reduziert. T2 - Langzeitverhalten warmfester Stähle und Hochtemperaturwerkstoffe CY - Online meeting DA - 27.11.2020 KW - HIP KW - Superlegierung KW - Kriechen PY - 2020 SN - 978-3-946885-95-5 VL - 2020 SP - 28 EP - 39 PB - Forschungsvereinigung Warmfeste Stähle und Hochtemperaturwerkstoffe AN - OPUS4-51796 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kupsch, Andreas A1 - Trappe, Volker A1 - Müller, Bernd R. A1 - Bruno, Giovanni T1 - Evolution of CFRP stress cracks observed by in situ X-ray refractive imaging N2 - Modern air-liners and wind turbine rotor blades are made up primarily of fiber reinforced plastics. Failure of these materials heavily impairs the serviceability and the operational safety. Consequently, knowledge of the failure behavior under static and cyclic loads is of great interest to estimate the operational strength and to compare the performance of different materials. Ideally, the damage evolution under operational load is determined with in-situ non-destructive testing techniques. Here, we report in-situ synchrotron X-ray imaging of tensile stress induced cracks in carbon fiber reinforced plastics due to inter-fiber failure. An inhouse designed compact tensile testing machine with a load range up to 15 kN was integrated into the beamline. Since conventional radiographs do not reveal sufficient contrast to distinguish cracks due to inter-fiber failure and micro cracking from fiber bundles, the Diffraction Enhanced Imaging (DEI) technique is applied in order to separate primary and scattered (refracted) radiation by means of an analyzer crystal. This technique allows fast measurements over large fields-of-view and is ideal for in-situ investigations. T2 - 12th BESSY@HZB User Meeting 2020 CY - Online meeting DA - 10.12.2020 KW - Carbon Fiber Reinforced Plastics KW - Crack evolution KW - Diffraction Enhanced Imaging KW - In situ tensile test KW - X-ray refraction PY - 2020 AN - OPUS4-51802 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mrkwitschka, Paul A1 - Abram, Sarah-Luise A1 - Kuchenbecker, Petra A1 - Würth, Christian A1 - Rühle, Bastian A1 - Resch-Genger, Ute A1 - Hodoroaba, Vasile-Dan T1 - Fine iron oxide nanoparticles as a candidate reference material for reliable measurement of particle size N2 - Background, Motivation and Objective Nanomaterials are at the core of some of the 21st century’s most promising technologies. In order to utilize and rationally design materials at the nanoscale the reliable characterization of their physico-chemical properties is highly important. Furthermore, the European Commission has taken measures via the REACH Regulations to control the classification of nanomaterials. REACH Annexes which entered into force in January 2020 require manufacturers to register nanomaterials that are traded in larger quantities (at least 1 ton). Every powder or dispersion where 50% (number distribution) of the constituent particles have sizes ≤ 100 nm in at least one dimension are defined as a nanomaterial. This creates a need for both industrial manufacturers and research and analytical service facilities to reliably characterize potential nanomaterials. Currently, BAM is working on developing reference nanoparticles, which shall expand the scarce list of worldwide available nano reference materials certified for particle size distribution, but also targeting other key parameters such as shape, structure (including porosity) and functional properties. Thus, candidate materials are considered to complement the already available spherical and monodisperse silica, Au and polystyrene reference nanoparticles, e.g. iron oxide and titanium oxide, with an average atomic number between those of silica and gold. Particularly for the imaging by electron microscopies, new nanoparticles of well-defined size in the range of 10 nm are decisive for the accurate particle segmentation by setting precise thresholds. Statement of Contribution/Methods Synthesis: Highly monodisperse iron oxide nanoparticles can be synthesized in large quantities by thermal decomposition of iron oleate or iron acetylacetonate precursors in high boiling solvents such as octadecene or dioctyl ether in the presence of oleic acid and oleylamine as capping agents. Scanning Electron Microscope: An SEM of type Supra 40 from Zeiss has been used including the dedicated measurement mode transmission in SEM (STEM-in-SEM) with a superior material contrast for the nanoparticle analysis. The software package ImageJ has been used for the analysis of the STEM-in-SEM images and to determine the particle size distribution. Dynamic Light scattering (DLS): Particles in suspension were measured in comparison by means of Zetasizer Nano (Malvern Panalytical; cumulants analysis) and NanoFlex (Microtrac; frequency power spectrum). Results/Discussion In this study iron oxide nanoparticles synthesized at BAM and pre-characterized by DLS, SEM (including the transmission mode STEM-in-SEM) are presented. The particles are spherical and highly monodisperse with sizes slightly larger than 10 nm. T2 - Nanosafe 2020 CY - Online meeting DA - 16.11.2020 KW - Reference nanomaterials KW - Imaging techniques KW - Size and size distribution KW - Reliable characterization KW - Iron oxide nanoparticles PY - 2020 AN - OPUS4-51767 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kuchenbecker, Petra T1 - Praktische Erfahrungen zur Granulometrie von Pulvern im Submikron- und Nanobereich N2 - Der Vortrag beleuchtet insbesondere die Herausforderungen die sich bei der Dispergierung der Nanopulver aufgrund der hohen Adhäsivkräfte ergeben. Die Bewertung der Probenpräparation ist nur indirekt zugänglich, aber essentiell für die Zuverlässigkeit der Messergebnisse. Anhand von Beispielen werden Lösungsvorschläge aufgezeigt. Der Vortrag schließt mit einem Vorschlag zur Strategie der Herangehensweise bei der Partikelgrößenbestimmung von Nanopulvern. T2 - Sitzung des Fachausschusses "Material- und Prozessdiagnostik" der Deutschen Keramischen Gesellschaft: Zuverlässige granulometrische Charakterisierung von Mikro- und Nanopulvern – Voraussetzung für optimierte Keramikwerkstoffe in der Energietechnik CY - Online meeting DA - 19.11.2020 KW - Nano-powder KW - particle size determination KW - dispersion KW - sample preparation PY - 2020 AN - OPUS4-51665 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fedelich, Bernard A1 - Grützner, Stefan A1 - Haftaoglu, Cetin A1 - Kindrachuk, Vitaliy A1 - Vöse, Markus T1 - Möglichkeiten und Grenzen der rechnerischen Bewertung der Lebensdauer von Bauteilen unter TMF: Viskoplastische Modelle N2 - In diesem Vortrag wird auf einige noch offene Frage zur Anwendung der viskoplastischen Modellierung bei Hochtemperaturermüdung. Insbesondere auf das Problem der Parameterbestimmung wird eingegangen. T2 - Workshop "Konstitutive Viskoplastische Materialmodelle" CY - Institut für Werkstoffkunde (IfW), Technische Universität Darmstadt, Germany DA - 06.11.2019 KW - TMF KW - Viskoplastisch KW - Modell KW - Hochtemperaturermüdung KW - LCF PY - 2019 AN - OPUS4-49611 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Akatsuka, C. A1 - Honma, T. A1 - Müller, Ralf A1 - Reinsch, Stefan A1 - Tanaka, S. A1 - Komatsu, T. T1 - Surface crystallization and gas bubble formation during conventional heat treatment in Na2MnP2O7 glass N2 - The crystallization behavior of sodium ion conductive Na2MnP2O7 glass was examined to clarify the crystallization mechanism. The formation of thermodynamically metastable phase, layered Na2MnP2O7, at the surface of the glass occurred. Heat treatment at 430 °C for 3 h lead to surface crystals of Na2MnP2O7 oriented with the (101) direction perpendicular to the sample surface. As the heat treatment temperature increased, the glass-ceramic samples deformed, and the presence numerous micro bubbles due to dissolved water was detected. KW - Glass-ceramic KW - Crystallization KW - Sodium ion batteries KW - Bubble formation KW - Phosphate PY - 2019 DO - https://doi.org/10.1016/j.jnoncrysol.2019.01.030 VL - 510 SP - 36 EP - 41 PB - Elsevier B.V. AN - OPUS4-49618 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Orlov, N. K. A1 - Evdokimov, P. V. A1 - Milkin, P. A. A1 - Garshev, A. V. A1 - Putlayev, V. I. A1 - Grebenev, V. V. A1 - Günster, Jens T1 - Phase equilibria in CaNaPO4-CaKPO4 system and their influence on formation of bioceramics based on mixed Ca-K-Na phosphates N2 - An investigation of the two-component phase diagram of the CaNaPO4- CaKPO4system performed using various analysis techniques is reported. The continuous solid solution series of α-CaMPO4 existing above 700 °C undergoes eutectoid decomposition during cooling to β-CaMPO4-based solid solutions enriched with Na and K, and to an intermediate nonstoichiometric compound with an ideal composition of CaK0.6Na0.4PO4. All three compounds exhibit significant volumetric effects associated with first-order phase transitions, with positive volume changes under cooling for the intermediate compound. Increased K content in ceramics based on CaKyNa1-yPO4 compositions enhances the strength properties of those ceramics, including their fracture toughness, which is associated with increased density. Increased K content also has a smaller effect of inducing phase transformations accompanied by strong volume changes. KW - Phase transformations KW - Bioceramics KW - Mixed Ca-K-Na phosphates KW - Na and K rhenanites KW - Phase diagram PY - 2019 DO - https://doi.org/10.1016/j.jeurceramsoc.2019.07.044 VL - 39 IS - 16 SP - 5410 EP - 5422 PB - Elsevier Ltd. AN - OPUS4-49621 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Orlov, N. K. A1 - Milkin, P. V. A1 - Evdokimov, P. A. A1 - Putlayev, V. I. A1 - Günster, Jens T1 - Sintering of sodium and potassium tcp based ceramic for bone grafting application N2 - Biomaterials for bone replacement and grafting should possess sufficient strength, be bioresorbable and demonstrate osteoconductive and osteoinductive properties. However, resorption of modern materials for bone grafting (hydroxyapatite (HA) and tricalcium phosphate (TCP)) is reported, in some cases, to be not enough, this is why the search for more soluble compounds compared to HA and TCP looks very perspective. A possible way to increase ceramics solubility leads to partial substitution of Ca2+ -ions in Ca3(PO4)2 by alkali cations, like Na+ or/and K+. Improvement of solubility stems from decreasing lattice energy of a substituted phase, as well as the 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 the 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 the study of sintering of the ceramics mentioned above highly important. To control Ca3(PO4)2 - CaKPO4 - CaNaPO4 based ceramic microstructure it is necessary to know possible phase transformations in the system and the way to manage microstructure by sintering schedule or sintering process. In this work, an isothermal section for phase diagram of Ca3(PO4)2 - CaKPO4 - CaNaPO4 ternary system is studied with several techniques. According to the XRD of quenched samples, this phase triangle has four single-phase areas at 1200˚C (Figure 1). It was shown that single-phase CaK0.6Na0.4PO4 cannot be sintered to full-dense ceramics by conventional sintering regardless time-temperature schedule. Two-step sintering technique, beneficial in the case of HA-ceramics, was unsuccessful in all cases of calcium-alkali phosphate compositions. However, field-assisted sintering techniques like, e.g. Spark Plasma Sintering (SPS), can overcome this problem due to significant impact on grain boundary diffusion. In connection with this fact, grains grow much slower retaining sintering process in a pore control regime. In this work CaK0.6Na0.4PO4 low-porous ceramics was also fabricated by FAST-methods of sintering. Moreover, other alternative sintering techniques, such as reaction sintering, may be useful in accelerating ions diffusion but stopping excessive grain growth.Strength properties of ceramics were evaluated by B3B-testing, micro- and nanoindentation techniques. Fracture toughness also becomes higher with potassium content increase, guiding porosity level. Resorption properties of sintered ceramics were studied in different solutions with pH=5 and 7.4. Acknowledgements. The research of sintering processes in calcium phosphate materials were funded by RFBR according to the research project № 18-33-00974. T2 - XVI ECerS Conference 2019 CY - Turin, Italy DA - 16.06.2019 KW - Phase transformations KW - Bioceramics KW - Mixed Ca-K-Na phosphates KW - Na and K rhenanites KW - Phase diagram PY - 2019 AN - OPUS4-49622 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 - Many of the most successful and precise additive manufacturing (AM) technologies are based on the deposition layer-by-layer of a flowable powder. Since the first pioneering work at the end of the 1980th many developments have been introduced, greatly extending the use of different materials, improving the physical properties of the components built and enhancing the accuracy of the process. Still very important issues remain nowadays, hampering a completely autonomous production of parts and even restricting the freedom of design by means of these technologies. One of the major issues is the low density and stability of the parts during the building process, which implies the need of support structures: The powder bed surrounding the part has an essential role, since it should support the structure during building, until it’s ready for removal. Moreover, the microstructure of the powder bed is a template for the microstructure of the part produced. In this context, the use of submicron ceramic powders is still a challenge. Three approaches for the stabilization and densification of powder beds will be presented: The Layerwise Slurry Deposition process LSD, the gas flow assisted powder deposition and the Laser Induced Slipcasting (LIS) of ceramic powder compacts. T2 - 43rd International Conference and Exposition on Advanced Ceramics and Composites (ICACC 2019) CY - Daytona Beach, FL, USA DA - 27.01.2019 KW - Ceramics KW - Additive Manufacturing PY - 2019 AN - OPUS4-49627 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Günster, Jens T1 - Powder-based Additive Manufacturing at Micro-Gravity N2 - Are we ready for putting a human footprint on Mars? Obviously, it is possible to send technologically challenging missions to our earth neighbors with a high level of complexity, such as enabling autonomous planetary mobility. As humanity contemplates mounting manned missions to Mars, strategies need to be developed for the design and operation of hospitable environments safely working in space for years. Humans require water and air provided by complicated equipment. Its safe operation is a great challenge and implies being prepared for all eventualities. Instead of foreseeing and preparing for all possible scenarios of machine failures and accidents, it appears logic taking advantage of the flexibility of humans and providing essential equipment for the reaction on critical situations. The supply of spare parts for repair and replacement of lost equipment would be one key pillar of such a strategy. Bearing in mind the absolute distance and flight trajectories for manned missions to Mars, supplying spare parts from Earth is impossible. Thus, in space manufacturing remains the only option for a timely supply. With a high flexibility in design and the ability to manufacture ready to use components directly from a computer aided model, additive manufacturing technologies appear extremely attractive. For metal parts manufacturing the Laser Beam Melting process is the most widely used additive manufacturing process in industrial application. However, envisioning the handling of metal powders in the absence of gravitation is one prerequisite for its successful application in space. A gas flow throughout the powder bed has been successfully applied to compensate for missing gravitational forces in micro gravity experiments. The so-called Gas Flow Assisted Powder Deposition is based on a porous building platform acting as a filter for the fixation of metal particles in a gas flow driven by a pressure difference maintained by a vacuum pump. T2 - 1st Sino-German Workshop on 3D Printing in Space CY - Beijing, China DA - 20.02.2019 KW - Zero-g KW - Additive Manufacturing KW - µ-gravity PY - 2019 AN - OPUS4-49628 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Günster, Jens T1 - Powder-based Additive Manufacturing at Micro-Gravity N2 - Are we ready for putting a human footprint on Mars? Obviously, it is possible to send technologically challenging missions to our earth neighbors with a high level of complexity, such as enabling autonomous planetary mobility. As humanity contemplates mounting manned missions to Mars, strategies need to be developed for the design and operation of hospitable environments safely working in space for years. Humans require water and air provided by complicated equipment. Its safe operation is a great challenge and implies being prepared for all eventualities. Instead of foreseeing and preparing for all possible scenarios of machine failures and accidents, it appears logic taking advantage of the flexibility of humans and providing essential equipment for the reaction on critical situations. The supply of spare parts for repair and replacement of lost equipment would be one key pillar of such a strategy. Bearing in mind the absolute distance and flight trajectories for manned missions to Mars, supplying spare parts from Earth is impossible. Thus, in space manufacturing remains the only option for a timely supply. With a high flexibility in design and the ability to manufacture ready to use components directly from a computer aided model, additive manufacturing technologies appear extremely attractive. For metal parts manufacturing the Laser Beam Melting process is the most widely used additive manufacturing process in industrial application. However, envisioning the handling of metal powders in the absence of gravitation is one prerequisite for its successful application in space. A gas flow throughout the powder bed has been successfully applied to compensate for missing gravitational forces in micro gravity experiments. The so-called Gas Flow Assisted Powder Deposition is based on a porous building platform acting as a filter for the fixation of metal particles in a gas flow driven by a pressure difference maintained by a vacuum pump. T2 - 2nd Sino-German Workshop on 3D Printing in Space CY - Berlin, Germany DA - 28.10.2019 KW - µ-gravity KW - Additive Manufacturing KW - Zero-g PY - 2019 AN - OPUS4-49629 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rabe, Torsten T1 - Alternative Verfahren zur Strukturierung von Grünfolien und Laminaten N2 - Die Strukturierung keramischer Grünfolien und Laminate ist ein wesentlicher Prozessschritt in der keramischen Multilayer-Technologie und begründet die funktionelle Vielfalt keramischer Multilayer. Benötigt wird die Grünbearbeitung für die Herstellung elektrischer und thermischer Vias sowie innerer Kavitäten und Kanäle für Transport und Lagerung von Gasen und Flüssigkeiten in hochintegrierten Schaltungsträgern, Sensoren und Reaktoren. Standardverfahren in der industriellen Fertigung sind Heißschneiden, Stanzen und Laserbearbeitung. Darüber hinaus werden auch Bohren, Fräsen, Sägen und Heißprägen verwendet. Über die Erprobung weiterer Verfahren wie Wasserstrahlschneiden, Dampfstrahlätzen und Powder Blasting wird in der Literatur berichtet. Im Vortrag werden spezifische Vor- und Nachteile der eingesetzten Verfahren beleuchtet. Abschließend werden die Kriterien für die Auswahl des optimalen Strukturierungsverfahrens diskutiert. Zusammensetzung und Gefüge sowie die dadurch bedingten mechanischen und thermomechanischen Eigenschaften sowie das Absorptionsverhalten von Grünfolien sind sehr unterschiedlich. Daraus resultieren unterschiedliche optimale Bearbeitbarkeitsparameter. T2 - DKG-Seminar "Foliengieß- und Schlitzdüsenverfahen" CY - Hermsdorf, Germany DA - 05.11.2019 KW - Stanzen KW - Keramische Folien KW - Laserbearbeitung KW - Grünfolieneigenschaften PY - 2019 AN - OPUS4-49742 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pelegrina, J. L. A1 - Olbricht, Jürgen A1 - Yawny, A. A1 - Eggeler, G. T1 - Temperature-induced transformations and martensitic reorientation processes in ultra-fine-grained Ni rich pseudoelastic NiTi wires studied by electrical resistance N2 - Temperature-induced, stress-induced martensitic phase transitions and martensite reorientation process in Ni rich (50.9 at.%) NiTi pseudoelastic NiTi wires with ultra-fine grained (UFG) microstructure were studied by electrical resistance measurements. Measurements of the electrical resistance as a function of temperature at different constant mechanical loads accompanied by complementary experiments with variable loads at constant temperature were performed. Results show that the transformation mechanisms in UFG microstructures exhibit a higher level of complexity when compared with those characterizing the behavior of other microstructures (e.g., recrystallized or larger grains size). It was found that a threshold stress level below 150 MPa delimits the transition from a homogeneous (low stress) to localized but reversible Lüders type transformation (high stress) when the transformations are induced under constant applied stress and that reorientation processes require stresses of 100 MPa in the present UFG wires. Even though the strain evolutions do not always show two distinct yielding events during cooling or heating, electrical resistance measurements proved that a two-step transformation involving R-phase and B19' martensite was always present in the extended range of temperatures and stresses investigated here. KW - Shape memory alloys KW - NiTi KW - Martensitic transformation KW - Electrical resistance PY - 2018 DO - https://doi.org/10.1016/j.jallcom.2017.12.009 SN - 0925-8388 VL - 735 SP - 2574 EP - 2583 PB - Elsevier AN - OPUS4-43549 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bresch, Sophie T1 - Einfluss der Pulversynthese auf die Eigenschaften thermoelektrischer Oxide N2 - Calciumcobaltit und Calciummanganat gehören zu den vielversprechendsten thermoelektrischen Oxiden im Temperaturbereich zwischen 600 °C und 800 °C an Luft. Mittels thermoelektrischer Generatoren kann ein Temperaturgradient direkt in elektrische Leistung umgewandelt werden. Für die kostengünstige Pulverherstellung von Funktionsmaterialien wird im industriellen Maßstab meist die Festphasenreaktion (bzw. Kalzinierung) verwendet. Da es sich dabei um einen Hochtemperaturprozess handelt, ist diese Kalzinierung sehr energieintensiv. In der Literatur werden sehr unterschiedliche Prozessbedingungen zur Pulversynthese thermoelektrischer Oxide genutzt. Soweit dem Autor bekannt, ist keine systematische Untersuchung des Einflusses der Pulversynthesebedingungen auf die thermoelektrischen Eigenschaften publiziert. Deshalb wurde eine systematische Untersuchung des Einflusses der Pulversynthesebedingungen (Temperatur, Haltezeit, Partikelgröße, Wiederholungen) auf die thermoelektrischen Eigenschaften von Calciumcobaltit und Calciummanganat durchgeführt. Es konnte gezeigt werden, dass sich ein höherer Energieeintrag während der Kalzinierung negativ auf die thermoelektrischen Eigenschaften auswirkt. T2 - Seminar des Lehrstuhls für Funktionsmaterialien CY - Universität Bayreuth, Bayreuth, Germany DA - 12.01.2018 KW - Kalzinierung KW - Thermoelektrika KW - Calciummanganat KW - Calciumcobaltit PY - 2018 AN - OPUS4-43772 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thiede, Tobias A1 - Mishurova, Tatiana A1 - Cabeza, S. A1 - Nadammal, Naresh A1 - Bode, Johannes A1 - Kromm, Arne A1 - Haberland, C. A1 - Bruno, Giovanni T1 - An assessment of bulk residual stress in selective laser melted Inconel 718 N2 - 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. T2 - ECNDT 2018 CY - Götheburg, Sweden DA - 11.06.2018 KW - Additive manufacturing KW - Ressidual stress KW - Neutron diffraction PY - 2018 AN - OPUS4-45761 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thiede, Tobias A1 - Mishurova, Tatiana A1 - Cabeza, S. A1 - Nadammal, Naresh A1 - Bode, Johannes A1 - Haberland, C. A1 - Bruno, Giovanni T1 - An assessment of bulk residual stress in selective laser melted Inconel 718 N2 - 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. T2 - VAMAS - Workshop CY - BAM, Berlin, Germany DA - 25.06.2018 KW - Additive manufacturing KW - Neutron diffraction KW - Ressidual stress PY - 2018 AN - OPUS4-45762 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schilling, Markus A1 - Niebergall, Ute A1 - Alig, I. A1 - Oehler, H. A1 - Lellinger, D. A1 - Meinel, Dietmar A1 - Böhning, Martin T1 - Crack propagation in PE-HD induced by environmental stress cracking (ESC) analyzed by several imaging techniques N2 - 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. KW - Environmental stress cracking (ESC) KW - Slow crack growth (SCG) KW - Full notch creep test (FNCT) KW - X-ray computed tomography (CT) KW - Laser scanning microscopy (LSM) KW - Scanning acoustic microscopy (SAM) PY - 2018 DO - https://doi.org/10.1016/j.polymertesting.2018.08.014 SN - 0142-9418 SN - 1873-2348 VL - 70 SP - 544 EP - 555 PB - Elsevier AN - OPUS4-45766 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Epishin, A. A1 - Fedelich, Bernard A1 - Nolze, Gert A1 - Schriever, Sina A1 - Feldmann, Titus A1 - Farzik Ijaz, M. A1 - Viguier, B. A1 - Poquillon, D. A1 - Le Bouar, Y. A1 - Ruffini, A. A1 - Finel, A. T1 - Creep of single crystals of nickel-based superalloys at ultra-high homologous temperature N2 - 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. T2 - 3rd European Conference on Superalloys (‘Eurosuperalloys 2018’) CY - Oxford, UK DA - 9.9.2018 KW - Single-crystal KW - Superalloy KW - Creep KW - Isostatic hot pressing (HIP) PY - 2018 DO - https://doi.org/10.1007/s11661-018-4729-6 SN - 1073-5623 SN - 1543-1940 VL - 49A IS - 9 SP - 3973 EP - 3987 PB - Springer Sciences & Business Media CY - New York, NY AN - OPUS4-45660 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Waurischk, Tina A1 - Müller, Ralf A1 - Behrens, H. A1 - Deubener, J. A1 - Balzer, R. A1 - Kiefer, P. T1 - The influence of water as volatile on crack propagation in soda-lime silicate glass N2 - The talk was given at the Spring School of the SPP1594 in Hannover and summarizes the actual findings about crack growth in water bearing soda-lime silicate glass and a comparison to other oxide glasses. T2 - Spring School des SPP1594 CY - Hannover, Germany DA - 06.03.2018 KW - DCB KW - Soda-lime silicate glass KW - Crack growth KW - Vickers KW - Water speciation PY - 2018 AN - OPUS4-45699 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Waurischk, Tina A1 - Kiefer, P. A1 - Balzer, R. A1 - Reinsch, Stefan A1 - Müller, Ralf A1 - Deubener, J. A1 - Behrens, H. T1 - Wasser und Risswachstum in Silicatgläsern N2 - 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. T2 - 1. Fachsymposium der Glasapparatebauer CY - Munich, Germany DA - 19.04.2018 KW - Wasser KW - Risswachstum KW - Glas KW - Vickers KW - DCB PY - 2018 AN - OPUS4-45701 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Waurischk, Tina A1 - Balzer, R. A1 - Kiefer, P. A1 - Reinsch, Stefan A1 - Müller, Ralf A1 - Behrens, H. A1 - Deubener, J. T1 - Sub-critical crack growth in silicate glass N2 - 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. T2 - 92nd Annual Meeting of the German Society of Glass Technology in Conjunction with the Annual Meetings of the Czech Glass Society & the Slovak Glass Society CY - Bayreuth, Germany DA - 28.05.2018 KW - Risswachstum KW - DCB KW - Glas PY - 2018 AN - OPUS4-45702 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kiefer, P. A1 - Deubener, J. A1 - Waurischk, Tina A1 - Balzer, R. A1 - Reinsch, Stefan A1 - Müller, Ralf A1 - Behrens, H. T1 - Statistical analysis of Vickers induced subcritical crack growth in soda-lime silicate glasses N2 - 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. T2 - 92nd Annual Meeting of the German Society of Glass Technology in Conjunction with the Annual Meetings of the Czech Glass Society & the Slovak Glass Society CY - Bayreuth, Germany DA - 28.05.2018 KW - Crack growth KW - Soda-lime silicate glass KW - Vickers PY - 2018 AN - OPUS4-45703 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kiefer, P. A1 - Deubener, J. A1 - Waurischk, Tina A1 - Balzer, R. A1 - Reinsch, Stefan A1 - Müller, Ralf A1 - Behrens, H. T1 - Subcritical crack growth in water bearing soda-lime silicate glasses N2 - 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. T2 - 92nd Annual Meeting of the German Society of Glass Technology in Conjunction with the Annual Meetings of the Czech Glass Society & the Slovak Glass Society CY - Bayreuth, Germany DA - 28.05.2018 KW - Water speciation KW - Soda-lime silicate glass KW - Crack growth KW - Vickers PY - 2018 AN - OPUS4-45704 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kiefer, P. A1 - Balzer, R. A1 - Waurischk, Tina A1 - Reinsch, Stefan A1 - Müller, Ralf A1 - Behrens, H. A1 - Deubener, J. T1 - Statistical analysis of subcritical crack growth in water bearing soda-lime silicate glasses N2 - The talk was given at the PNCS-ESG 2018 in Saint Malo and summarizes the actual findings about Vickers induced crack growth in water bearing soda-lime silicate glasses. T2 - 15th International Conference on the Physics of Non-Crystalline Solids & 14th European Society of Glass Conference CY - Saint Malo, France DA - 09.07.2018 KW - Water speciation KW - Vickers KW - Crack growth KW - Soda-lime silicate glass PY - 2018 AN - OPUS4-45707 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Ralf A1 - Gaber, M. T1 - VACUUM HOT EXTRACTION (VHE-MS): Concentration, diffusion and degassing of volatiles N2 - Der Vortrag gibt eine Einführung in die Methode der Vakuumheißextraktion und beschreibt die Anwendungsmöglichkeiten der an der BAMN betriebenen Anlage. T2 - Seminar Instrumentelle Analytik, Fakultät III Prozesswissenschaften, Lehrstuhl Keramik TU Berlin CY - TU Berlin, Germany DA - 26.1.2018 KW - Gasabgabe KW - Diffusion KW - Gasgehalt PY - 2018 AN - OPUS4-45665 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sharatchandra Singh, W. A1 - Stegemann, Robert A1 - Kreutzbruck, Marc A1 - Mukhopadhyay, C. K. A1 - Purnachandra Rao, B. T1 - Mapping of Deformation-Induced Magnetic Fields in Carbon Steels Using a GMR Sensor Based Metal Magnetic Memory Technique N2 - 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. KW - GMR KW - Metal Magnetic Memory KW - 3D-finite element modeling KW - Plastic deformation KW - Carbon steel PY - 2018 DO - https://doi.org/10.1007/s10921-018-0470-8 SN - 0195-9298 VL - 37 IS - 2 SP - 21 PB - Springer US AN - OPUS4-45667 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Ralf A1 - Gaber, M. A1 - Reinsch, Stefan T1 - Thermal Analysis and Relaxation Phenomena in Oxide Glasses N2 - Wasser beeinflusst empfindlich eine Vielzahl von thermisch aktivierten Relaxationsphänomenen in Gläsern wie die Spannungsrelaxation, das unterkritische Risswachstum, innere Reibung, Viskosität, Sinterverhalten und Kristallisation. Thermische Methoden können dabei wesentliche Beiträge zum Verständnis dieser Phänomene liefern. Der Vortrag gibt einen Überblick über die Möglichkeiten der VakuumHeißExtraktion (VHE) zur Untersuchung des Wassergehalts, des Wasserabgabeverhaltens und der Wassermobilität sowie über den Einfluss des Wassers auf die innere Reibung (DMA). N2 - 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. T2 - Spring school DFG SPP 1594 CY - Hannover, Germany DA - 06.03.2018 KW - Wasser KW - Silicatglas KW - Relaxationsphänomene KW - Relaxation KW - Thermoanalytical Methods KW - Glass KW - Dissolved water PY - 2018 AN - OPUS4-45668 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Ralf A1 - Reinsch, Stefan A1 - Deubener, J. A1 - Behrens, H. T1 - Wasser in Silicatglas N2 - Der Vortrag gibt einen Überblick über den Stand des Wissens zum strukturellen Einbau von Wasser in Silicat- und Boratgläsern, den Einfluss des gelösten Wassers auf deren Viskosität sowie zu den strukturellen Vorstellungen zum Wassertransport. T2 - 1. Fachsymposium der Glasapparatebauer CY - Munich, Germany DA - 19.04.2018 KW - Wasser KW - Glass KW - Struktur PY - 2018 AN - OPUS4-45669 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Ralf T1 - Glass Sintering with Concurrent Crystallization and Foaming N2 - 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. T2 - 7th Int Congress on Ceramics, Symposium Frontiers of Glass Science CY - Iguacu, Brazil DA - 17.06.2018 KW - Glass KW - Powder KW - Sintering KW - Foaming PY - 2018 AN - OPUS4-45670 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Grelle, Tobias A1 - Probst, Ulrich A1 - Jaunich, Matthias A1 - Skrotzki, Birgit A1 - Wolff, Dietmar T1 - Creep investigations on aluminum seals for application in radioactive waste containers N2 - 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. T2 - International Conference on Aluminum Alloys CY - Montreal, Canada DA - 17.06.2018 KW - Metal seal KW - Creep KW - Long-term behavior PY - 2018 SN - 978-1-926872-41-4 SP - 1 EP - 2 AN - OPUS4-45844 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Welter, T. A1 - Deubener, J. A1 - Reinsch, Stefan A1 - Marzok, Ulrich A1 - Müller, Ralf T1 - Glass structures with low H2-diffusity N2 - 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. T2 - 92. Glastechnische Tagung der DGG CY - Bayreuth, Germany DA - 28.05.2018 KW - Hydrogen permeability KW - Atomic packing factor KW - Glass composition KW - Diffusion coefficient PY - 2018 AN - OPUS4-45900 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Eisermann, René A1 - Schukar, Marcus A1 - Nagel, Lukas A1 - Hickmann, Stefan A1 - Munzke, Dorit A1 - Trappe, Volker T1 - Characterising the material degradation of inner pressure-loaded GFRP-tube specimens using distributed strain sensing N2 - 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. T2 - Sensoren und Messsysteme - 19. ITG/GMA-Fachtagung CY - Nürnberg, Germany DA - 26.06.2018 KW - Distributed fibre optic sensors KW - Optical backscatter reflectometry KW - Swept wavelength interferometry (SWI) KW - Structural health monitoring (SHM) KW - Composite structures KW - Optical fibre PY - 2018 UR - https://ieeexplore.ieee.org/document/8436172/ SN - 978-3-8007-4683-5 SP - 239 EP - 242 PB - VDE VERLAG GMBH CY - Berlin AN - OPUS4-45887 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Erdmann, Maren A1 - Kleinbub, Sherin A1 - Böhning, Martin A1 - Niebergall, Ute A1 - Koerdt, Andrea T1 - Initial attachment of bacteria on PE-HD by fluorescence microscopy and colony-forming unit N2 - 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). T2 - MoDeSt2018 CY - Tokio, Japan DA - 02.09.2018 KW - PE-HD KW - Initial attachment KW - UV-irradiation PY - 2018 AN - OPUS4-45893 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Erdmann, Maren A1 - Wachtendorf, Volker A1 - Böhning, Martin A1 - Niebergall, Ute T1 - PE-HD as a polymeric fuel storage tank material: Photooxidation, fuel sorption and long-term storage N2 - 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. T2 - MoDeSt2018 CY - Tokio, Japan DA - 02.09.2018 KW - PE-HD KW - Biodiesel KW - UV-irradiation KW - Long-term storage KW - Diesel PY - 2018 AN - OPUS4-45894 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - de Camp, N. V. A1 - Kalinka, Gerhard A1 - Bergeler, J. T1 - Light-cured polymer electrodes for non-invasive EEG recordings N2 - 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? KW - Light curing KW - Polymer KW - Electric conductivity PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-459803 UR - https://rdcu.be/7aPD DO - https://doi.org/10.1038/s41598-018-32304-6 SN - 2045-2322 VL - 8 IS - 14041 SP - 1 EP - 9 PB - Nature Publishing Group CY - London AN - OPUS4-45980 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kromm, Arne A1 - Cabeza, S. A1 - Mishurova, Tatiana A1 - Nadammal, Naresh A1 - Thiede, Tobias A1 - Bruno, Giovanni T1 - Residual Stresses in Selective Laser Melted Samples of a Nickel Based Superalloy N2 - 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. T2 - European Conference on Residual Stresses - ECRS10 CY - Leuven, Belgium DA - 11.09.2018 KW - Additive Manufacturing KW - Selective Laser Melting KW - Residual Stresses PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-459818 SN - 978-1-94529-189-0 SN - 978-1-94529-188-3 DO - https://doi.org/10.21741/9781945291890-41 SN - 2474-395X SN - 2474-3941 VL - 6 SP - 259 EP - 264 PB - Materials Research Forum LLC CY - Millersville, PA 17551, USA AN - OPUS4-45981 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fedelich, Bernard A1 - Epishin, A. A1 - Nolze, Gert A1 - Schriever, Sina A1 - Feldmann, Titus A1 - Ijaz, M. A1 - Viguier, B. A1 - Poquillon, D. A1 - Le Bouar, Y. A1 - Ruffini, A. A1 - Finel, A. T1 - Creep of single-crystals of nickel-base superalloys at ultra-high homologous temperature N2 - 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. T2 - EuroSuperalloys 2018 CY - Oxford, UK DA - 09.09.2018 KW - Nickel-base superalloys KW - Single-crystals KW - Creep PY - 2018 AN - OPUS4-45989 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Welter, T. A1 - Marzok, Ulrich A1 - Reinsch, Stefan A1 - Müller, Ralf A1 - Deubener, J. T1 - Silicate glass structures with low hydrogen permeability N2 - 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. T2 - 15th International Conference on the Physics of Non-Crystalline Solids & 14th European Society of Glass Conference CY - Saint Malo, France DA - 09.07.2018 KW - Diffusion coefficient KW - 3D glass structure model KW - Glass composition KW - Hydrogen permeation PY - 2018 AN - OPUS4-45911 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Deubener, J. A1 - Allix, M. A1 - Davis, M.J. A1 - Duran, A. A1 - Höche, T. A1 - Honma, T. A1 - Komatsu, T. A1 - Krüger, S. A1 - Mitra, I. A1 - Müller, Ralf A1 - Nakane, S. A1 - Pascual, M.J. A1 - Schmelzer, J.W. A1 - Zanotto, E.D. A1 - Zhou, S. T1 - Updated definition of glass-ceramics N2 - Glass-ceramics are noted for their unusual combination of properties and manifold commercialized products for consumer and specialized markets. Evolution of novel glass and ceramic processing routes, a plethora of new compositions, and unique exotic nano- and microstructures over the past 60 years led us to review the Definition of glass-ceramics. Well-established and emerging processing methods, such as co-firing, additive manufacturing, and laser patterning are analyzed concerning the core requirements of processing glass-ceramics and the Performance of the final products. In this communication, we propose a revised, updated definition of glass-ceramics, which reads “Glass-ceramics are inorganic, non-metallic materials prepared by controlled crystallization of glasses via different processing methods. They contain at least one type of functional crystalline phase and a residual glass. The volume fraction crystallized may vary from ppm to almost 100%”. KW - Glass-ceramics definition PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-464711 DO - https://doi.org/10.1016/j.jnoncrysol.2018.01.033 SN - 0022-3093 SN - 1873-4812 VL - 501 SP - 3 EP - 10 PB - Elsevier B.V. AN - OPUS4-46471 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kotaka, M. A1 - Honma, T. A1 - Komatsu, T. A1 - Shinozaki, K. A1 - Affatigato, M. A1 - Müller, Ralf T1 - Control of self-powdering phenomenon in ferroelastic β′-Gd2(MoO4)3 crystallization in boro-tellurite glasses N2 - Glasses with compositions of 21Gd2O3-63MoO3-(16-x)B2O3-xTeO2 (mol%) (x= 0, 2, 4, 8) were prepared using a conventional melt quenching technique, and the crystallization behavior of ferroelastic β′-Gd2 MoO4)3 Crystals was examined to clarify the mechanism of self-powdering phenomenon and to design bulk crystallized glasses. It was found that the self-powdering phenomenon appeared significantly during the crystallization at temperatures near the crystallization peak temperature, but the phenomenon is suppressed in the crystallization at temperatures much higher than the glass transition temperature. It was also found that the substitution of TeO2 for B2O3 in the base glasses suppresses the self-powdering phenomenon and consequently bulk crystallized glasses were obtained in the glass with x=8 mol%. The densities at room temperature of the base glasses are d =4.755–4.906 g/cm3, being much higher than the value of d=4.555 g/cm3 for β′-Gd2(MoO4)3 crystal. It is proposed that the stresses in the inside of crystals induced by large density differences (i.e., large molar volume differences) between the glassy phase and crystals might be relaxed effectively in the glasses containing TeO2 with weak TeeO bonds and fragile character. KW - Glass crystallization stress PY - 2018 DO - https://doi.org/10.1016/j.jnoncrysol.2017.12.006 SN - 0022-3093 SN - 1873-4812 VL - 501 SP - 85 EP - 92 PB - Elsevier B.V. AN - OPUS4-46472 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Ralf A1 - Agea Blanco, Boris A1 - Blaeß, Carsten A1 - Waurischk, Tina A1 - Reinsch, Stefan A1 - Behrens, H. T1 - Sintering and foaming of silicate N2 - 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 properties and complex shape. Powder processing, however, can substantially affect sinterability, e.g. by promoting surface crystallization. On the other hand, densification can be hindered by gas bubble formation for slow crystallizing glass powders. Against this background, we studied sintering and foaming of silicate glass powders with different crystallization tendency for wet milling and dry milling in air, Ar, N2, and CO2 by means of heating microscopy, DTA, Vacuum Hot Extraction (VHE), SEM, IR spectroscopy, XPS, and ToF-SIMS. In any case, foaming activity increased significantly with progressive milling. For moderately milled glass powders, subsequent storage in air could also promote foaming. Contrarily, foaming could be substantially reduced by milling in water and 10 wt% HCl. Although all powder compacts were uniaxially pressed and sintered in air, foaming was significantly affected by different milling atmosphere and was found most pronounced for milling in CO2 atmosphere. Conformingly, VHE studies revealed that foaming is mainly driven by carbonaceous species, even for powders milled in other gases. Current results of this study thus indicate that foaming is caused by carbonaceous species trapped on the glass powder surface. T2 - ICG Annual Meeting 2018 CY - Yokohama, Japan DA - 23.09.2018 KW - Foaming KW - Glass KW - Powder KW - Sintering PY - 2018 AN - OPUS4-46474 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Ralf A1 - Marzok, U. T1 - Hochtemperatur Laserprofilometrie (HTLP) N2 - Der Vortrag gibt einen Überblick über Funktionsweise und Anwendungsmöglichkeiten der an der BAM entwickelten Messmethode der Hochtemperatur-Laserprofilomtrie T2 - Seminar Instrumentelle Analytik, Fakultät III Prozesswissenschaften, Lehrstuhl Keramik TU Berlin CY - TU Berlin, Germany DA - 26.01.2018 KW - Sinterung KW - Hochtemperatur KW - Formerkennung PY - 2018 AN - OPUS4-46475 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Häberle, Nicolas A1 - Pittner, Andreas A1 - Rethmeier, Michael A1 - Falkenberg, Rainer A1 - Kahlcke, Ole T1 - Application of multi-phase viscoplastic material modelling to computational welding mechanics of grade-s960ql steel N2 - The sound numerical prediction of welding-induced thermal stresses, residual stresses, and distortions strongly depends on the accurate description of a welded material’s thermomechanical deformation behaviour. In this work, we provide experimental data on the viscoplastic deformation behaviour of a grade-s960ql steel up to a temperature of 1000 ◦C. In addition, a multi-phase viscoplastic material model is proposed, which accounts for the experimentally observed isothermal deformation behaviour of grade-s960ql steel base and austenitised material, as well as for athermal contributions that originate from solid-state phase transformations. The multi-phase viscoplastic and a classic rateindependent isotropic hardening material model were applied in the numerical simulations of both-ends-fixed bar Satoh tests and a single-pass gas metal arc weld. The influence of material modelling choices on the agreement between numerical simulation and experimental results is discussed, and recommendations for further work are given. KW - Residual stress KW - Viscoplasticity KW - Material modeling KW - Grade S960QL steel PY - 2018 DO - https://doi.org/10.1016/j.crme.2018.08.001 VL - 346 IS - 11 SP - 1018 EP - 1032 PB - Elsevier Masson SAS AN - OPUS4-46512 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Grelle, Tobias A1 - Probst, Ulrich A1 - Jaunich, Matthias A1 - Skrotzki, Birgit A1 - Wolff, Dietmar T1 - Creep Investigations on Aluminum Seals for Application in Radioactive Waste Containers N2 - 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. T2 - International Conference on Aluminum Alloys CY - Montreal, Canada DA - 17.06.2018 KW - Metal seal KW - Creep KW - Long-term behavior PY - 2018 AN - OPUS4-45843 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Skrotzki, Birgit A1 - Olbricht, Jürgen A1 - Kühn, Hans-Joachim T1 - Mechanische Werkstoffeigenschaften bei hoher Temperatur N2 - Der Vortrag behandelt die Herausforderungen bei der mechanischen Kennwertermittlung für Metalle bei hoher Temperatur. T2 - Festkolloquium 50 Jahre Institut für Werkstoffe CY - Bochum, Germany DA - 13.09.2018 KW - Kennwertermittlung KW - Mechanisches Verhalten KW - Hochtemperatur PY - 2018 AN - OPUS4-46014 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kuchenbecker, Petra T1 - Weiterentwicklung der VSSA-Screening-Methode zur Identifizierung von NanoPulvern N2 - 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. T2 - NanoDefine Follow-up Meeting CY - Frankfurt/ Main, Germany DA - 25.09.2018 KW - VSSA KW - Nano particle KW - Particle size KW - Nano screening PY - 2018 AN - OPUS4-46070 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zhandarov, S. A1 - Mäder, E. A1 - Kalinka, Gerhard A1 - Scheffler, C. A1 - Poitzsch, C. A1 - Fliescher, S. T1 - Investigation of interfacial strength parameters in polymer matrix composites: Compatibility and reproducibility N2 - 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. KW - Interface KW - Interfacial shear strength KW - Pull-out composite materials KW - Polymer matrix composites KW - Critical energy release rate KW - Geometrical factors PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-460918 DO - https://doi.org/10.1016/j.aiepr.2018.06.002 SN - 2542-5048 VL - 1 IS - 1 SP - 82 EP - 92 PB - Elsevier CY - Amsterdam AN - OPUS4-46091 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ghafafian, Carineh T1 - Betriebsfestigkeit von Reparaturstellen an Rotorblättern von Windkraftanlagen N2 - 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. T2 - Kolloquium Luftfahrzeugbau und Leichtbau, TU Berlin CY - Berlin, Germany DA - 18.06.2018 KW - Sandwich KW - Faserverstärkte Kunstoffe KW - Betriebsfestigkeit PY - 2018 AN - OPUS4-46026 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - von Hartrott, P. A1 - Metzger, M. A1 - Rockenhäuser, Christian A1 - Skrotzki, Birgit T1 - Lebensdauerbewertung von alternden Werkstoffen N2 - 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. KW - Aluminiumlegierung KW - Alterung KW - Mikrostruktur KW - Lebensdauervorhersage KW - Schädigung PY - 2018 DO - https://doi.org/10.1007/s35146-018-0085-8 SN - 0024-8525 SN - 2192-8843 VL - 79 IS - 10 SP - 72 EP - 76 PB - Springer AN - OPUS4-46064 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - von Hartrott, P. A1 - Metzger, M. A1 - Rockenhäuser, Christian A1 - Skrotzki, Birgit T1 - Lifetime assessment of aging materials N2 - 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. KW - Aluminum alloy KW - Aging KW - Microstructure KW - Lifetime prediction KW - Damage PY - 2018 DO - https://doi.org/10.1007/s38313-018-0084-7 SN - 2192-9114 VL - 79 IS - 10 SP - 64 EP - 68 PB - Springer AN - OPUS4-46065 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ghafafian, Carineh A1 - Trappe, Volker A1 - Nielow, Dustin T1 - Analysis of the fatigue strength of various repair concepts for wind turbine rotor blades N2 - 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. T2 - MSE Congress 2018 CY - Darmstadt, Germany DA - 26.09.2018 KW - Glass fiber reinforced polymers KW - Lightweight materials KW - Fatigue of sandwich structures KW - Wind turbine blades KW - Sandwich PY - 2018 AN - OPUS4-46102 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Orlov, Nikolai A1 - Milkin, P. A1 - Evdokimov, P A1 - Putlayev, V. A1 - Günster, Jens A1 - Nicolaides, Dagmar T1 - Bioceramics from Ca3(PO4)2 - CaKPO4 - CaNaPO4 system for bone replacement and grafting N2 - 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. T2 - Biomaterials and Novel Technologies for Healthcare, 2nd International Biennial Conference BioMaH CY - Frascati (Rome), Italy DA - 08.10.2018 KW - Bio Ceramics KW - Bioresorbable PY - 2018 AN - OPUS4-46035 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Falkenberg, Rainer T1 - A phase-field approach to fracture coupled with mass transport for the simulation of environmentally-assisted damage N2 - With the introduction of a mass transport mechanism the entire problem is subjected to a time frame that dictates the time-dependent action of soluted species on mechanical properties. A numerical framework within the phase-field approach is presented with an embrittlement-based coupling mechanism. The underlying functionals are expressed in terms of the displacement, mass concentration and crack phase-field. Within the phase-field approach the modelling of sharp crack discontinuities is replaced by a diffusive crack model facilitating crack initiation and complex crack topologies without the requirement of a predefined crack path. The isotropic hardening of the elasto-plastic deformation model and the local fracture criterion are affected by the species concentration. This allows for embrittlement and leads to an accelerated crack propagation. An extended mass transport equation for hydrogen embrittlement, accounting for mechanical stresses and deformations, is implemented. For stabilisation purposes a staggered scheme is applied to solve the system of partial differential equations by a multi-field finite-element method. A thermodynamically consistent coupling relation that accommodates the required mechanisms is presented. KW - Environmentally assisted cracking KW - Fracture mechanics KW - Crack propagation KW - Phase-field KW - Mass transport PY - 2018 DO - https://doi.org/10.1002/pamm.201710088 VL - 17 SP - 237 EP - 238 PB - Wiley-VCH Verlag GmbH & Co. KGaA CY - Weinheim AN - OPUS4-46435 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -