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 U6 - 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 U6 - 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 - Kindrachuk, Vitaliy A1 - Titscher, Thomas A1 - Unger, Jörg F. T1 - A Fourier transformation-based method for gradient-enhanced modeling of fatigue N2 - A key limitation of the most constitutive models that reproduce a Degradation of quasi-brittle materials is that they generally do not address issues related to fatigue. One reason is the huge computational costs to resolve each load cycle on the structural level. The goal of this paper is the development of a temporal Integration scheme, which significantly increases the computational efficiency of the finite element method in comparison to conventional temporal integrations. The essential constituent of the fatigue model is an implicit gradient-enhanced formulation of the damage rate. The evolution of the field variables is computed as amultiscale Fourier series in time.On a microchronological scale attributed to single cycles, the initial boundary value problem is approximated by linear BVPs with respect to the Fourier coefficients. Using the adaptive cycle jump concept, the obtained damage rates are transferred to a coarsermacrochronological scale associated with the duration of material deterioration. The performance of the developedmethod is hence improved due to an efficient numerical treatment of the microchronological problem in combination with the cycle jump technique on the macrochronological scale. Validation examples demonstrate the convergence of the obtained solutions to the reference simulations while significantly reducing the computational costs. KW - Accelerated temporal integration KW - Fourier series KW - Gradient-enhanced fatigue model PY - 2018 U6 - https://doi.org/10.1002/nme.5740 SN - 1097-0207 SN - 0029-5981 VL - 114 IS - 2 SP - 196 EP - 214 PB - Wiley AN - OPUS4-44008 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 U6 - 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 - 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 U6 - 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 - Hinrichs, R. A1 - Zen Vasconcellos, M.A. A1 - Österle, Werner A1 - Prietzel, C. T1 - Amorphization of graphite flakes in gray cast iron under tribological load N2 - A gray cast iron disc, which had been submitted to a heavy duty automotive brake test, was examined with energy filtered transmission electron microscopy. A graphite flake in a convenient angular position showed the shear interaction of graphite layers with the iron matrix in nano-scale resolution. Atomic layers of graphite were wedged into the ferritic bulk, allowing the entrance of oxygen and the subsequent formation of magnetite. The exfoliated few-layer graphene batches deformed heavily when forced into the matrix. When Raman spectra from the disc surface, which show distinctive carbonaceous bands, were compared with Raman spectra from graphite subjected to deformation in a shaker mill with different milling times, it could be seen that the shear stress on the brake surface was much more effective to induce disorder than the milling, where compressive and impact forces had been additionally exerted on the sample. During shear load the high anisotropy of elastic modulus in the graphite crystalline structure and the low adhesion between graphite basal planes allowed the exfoliation of wrinkled few-layer grapheme batches, causing the formation of more defect related Raman bands than the mechanical stress during high-energy milling. KW - Graphite KW - Shear load KW - Amorphization KW - EFTEM KW - Raman spectroscopy PY - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-469227 SN - 1516-1439 SN - 1980-5373 VL - 21 IS - 4 SP - e20171000, 1 EP - 6 PB - Universidade Federal de São Carlos CY - São Carlos AN - OPUS4-46922 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Koclega, Damian A1 - Petrzak, P. A1 - Kowalski, K. A1 - Rozmus-Gornikowska, M. A1 - Debowska, A. A1 - Jedrusik, M. T1 - Annealing effect on microstructure and chemical composition of Inconel 625 alloy N2 - Our research focused on Inconel 625 weld overlays on 16Mo3 steel boiler pipes. The Investigation focused on the characterization of changes in the microstructure and chemical composition after annealing. The annealing was performed for ten hours at temperatures from 600 to 1000°C. Changes in the microstructure were observed with a scanning and transmission electron microscope (SEM and TEM). The investigation was supplemented by hardness measurements. KW - Inconel 625 KW - Microsegregation KW - Annealing PY - 2018 U6 - https://doi.org/10.7494/mafe.2018.44.2.73 SN - 1230-2325 SN - 0860-6307 SN - 2300-8377 VL - 44 IS - 2 SP - 73 EP - 80 PB - AGH University of Science and Technology Press CY - Cracow AN - OPUS4-49659 LA - eng 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 U6 - 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 - 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 U6 - 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 - Reith, F. A1 - Rea, M.A.D. A1 - Sawley, P. A1 - Zammit, C.M. A1 - Nolze, Gert A1 - Reith, T. A1 - Rantanen, K. A1 - Bissett, A. T1 - Biogeochemical cycling of gold: Transforming gold particles from arctic Finland N2 - (Bio)geochemical cycling of gold (Au) has been demonstrated in present-day (semi)-arid, (sub)-tropical and temperate environment. Hereby biofilms on Au-bearing mineral- and Au-particle surfaces drive Au dispersion and reconcentration, thereby (trans)forming the particles. However, it is unknown if biogeochemical cycling of Au occurs in polar environments, where air temperatures can reach −40 °C and soils remain frozen for much of the year. Therefore, placer Au-particles, soils and waters were collected at two placer mining districts in arctic Finland, i.e., the Ivalojoki and Lemmenjoki goldfields. Sites were chosen based on contrasting settings ((glacio)-fluvial vs. glacial-till deposits) and depths (surface to 5m below current surface). Gold particles were studied using a combination of tagged 16S rRNA gene next generation sequencing and electron microscopic/microanalytical techniques. Across all sites a range of Au-particle morphologies were observed, including morphotypes indicative of Au dissolution and aggregation. Elevated Au concentrations indicative of Au mobility were detected in placer particle bearing soils at both districts. Typically Au-particles were coated by polymorphic biofilm layers composed of living and dead cells embedded in extracellular polymeric substances. Intermixed were biominerals, clays and iron-sulfides/oxides and abundant secondary Au morphotypes, i.e., nano-particles, microcrystals, sheet-like Au, branched Au networks and overgrowths and secondary rims. Biofilms communities were composed of Acidobacteria (18.3%), Bacteroidetes (15.1%) and Proteobacteria (47.1%), with β-Proteobacteria (19.5%) being the most abundant proteobacterial group. Functionally, biofilms were composed of taxa contributing to biofilm establishment, exopolymer production and nutrient cycling, abundant taxa capable of Au mobilization, detoxification and biomineralization, among them Cupriavidus metallidurans, Acinetobacter spp. and Pseudomonas spp., were detected. In conclusion, these results demonstrate that placer Au-particle transformation and Au dispersion occur in cold, arctic environments. This corroborates the existence of biogeochemical Au cycling in present-day cold environments. KW - Gold KW - Bacteria KW - Biogeochemistry KW - Mobility KW - Finland KW - Cupriavidus metallidurans KW - NGS PY - 2018 U6 - https://doi.org/10.1016/j.chemgeo.2018.03.021 SN - 0009-2541 VL - 483 SP - 511 EP - 529 PB - Elsevier AN - OPUS4-44805 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nolze, Gert A1 - Han, M. A1 - Chen, C. A1 - Zhao, G. A1 - Li, L. A1 - Yo, B. A1 - Huang, X. A1 - Zhu, Y. T1 - Blind lattice-parameter determination of cubic and tetragonal phases with high accuracy using a single EBSD pattern N2 - The Bravais lattices and their lattice parameters are blindly determined using electron backscatter diffraction (EBSD) patterns of materials with cubic or tetragonal crystal structures. Since the geometric relationships in a single EBSD pattern are overdetermined, the relative errors of determining the lattice parameters as well as the axial ratios are confined to about 0.7 ± 0.4% and 0.07 ± 0.03%, respectively, for ideal simulated EBSD patterns. The accuracy of the crystal orientation determination reaches about 0.06 ± 0.03°. With careful manual band detection, the accuracy of determining lattice parameters from experimental patterns can be as good as from simulated patterns, although the results from simulated patterns are often better than expermental patterns, which are lower quality and contain uncertain systematic errors. The reasonably high accuracy is obtained primarily because the detection of the diffracting-plane traces and zone axes is relatively accurate. The results here demonstrate that the developed procedure based on the EBSD technique presents a reliable tool for crystallographic characterization of the Bravais lattices of unknown phases. KW - EBSD KW - Bravais lattice KW - Lattice parameters KW - Kikuchi pattern PY - 2018 U6 - https://doi.org/10.1107/S2053273318010963 SN - 2053-2733 VL - 74 IS - 6 SP - 630 EP - 639 PB - International Union of Crystallography AN - OPUS4-46455 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 - 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 U6 - 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 - 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 U6 - 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 - 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 U6 - 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 U6 - 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 - JOUR A1 - Pfennig, A. A1 - Kranzmann, Axel T1 - Degradation of AISI 630 exposed to CO2-saturated saline aquifer at ambient pressure and 100 bar N2 - In general high alloyed steels are suitable as pipe steels for carbon capture and storage technology (CCS), because they provide sufficient resistance against the corrosive environment of CO2-saturated saline aquifer which serves as potential CCS-site in Germany. High alloyed martensitic steel AISI 630 has been proven to be sufficient resistant in corrosive environments, e.g. regarding heat, pressure, salinity of the aquifer, CO2-partial pressure), but reveals a distinct corrosion pattern in CCS environment. Therefore coupons of AISI 630 heat treated using usual protocols were kept at T=60 °C and ambient pressure as well as p=100 bar up to 8000 h in an a) water saturated supercritical CO2 and b) CO2-saturated synthetic aquifer environment similar to on-shore CCS-sites in the Northern German Basin. AISI 630 precipitates a discontinuous ellipsoidal corrosion layer after being exposed for more than 4000 hours. Best corrosion resistance in the CO2-saturated synthetic aquifer environment phase is achieved via normalizing prior to exposure. In water saturated supercritical CO2 tempering at medium temperatures after hardening gives lowest corrosion rates. Corrosion fatigue via push-pull tests with a series of 30 specimens was evaluated at stress amplitudes between 150 MPa and 500 MPa (sinusoidal dynamic test loads, R=-1; resonant frequency ~ 30 Hz). The endurance limit of AISI 630 is reduced by more than 50% when exposed to CCS environment (maximum number of cycles (10 x 106) at a stress amplitude of 150 MPa). KW - Corrosion Fatigue KW - High Cycle Fatigue KW - Steel KW - Ccs KW - Co2-Storage PY - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-503783 SN - 1819-544X SN - 1816-157X SP - 11 EP - 17 PB - INSInet Publications CY - Faisalabad AN - OPUS4-50378 LA - eng 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 U6 - 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 - Le, Quynh Hoa A1 - Bäßler, Ralph A1 - Knauer, S A1 - Jaeger, P A1 - Kratzig, Andreas A1 - Bettge, Dirk A1 - Kranzmann, Axel T1 - Droplet corrosion of CO2 transport pipeline steels in simulated oxyfuel flue gas N2 - The research focus of this study was set on the corrosion process of condensate as droplets on the surface of carbon steels (X52, X70) martensitic steel UNS S41500, and super austenite UNS N08031 in CO2 atmosphere with impurities at 278 K (to simulate the offshore transportation condition in a buried pipeline). The possibility of dew/droplet formation on the steel surface and wetting behavior of corresponding materials were evaluated by contact angle measurement in dense CO2 at 278 K. To observe the effect of impurities (SO2 and O2) on droplet corrosion process, exposure tests were carried out in the mixed atmosphere with a drop, 1 ‑ 10 µL in volume, of CO2 saturated ultra-pure water on steel surface. Comparable exposure tests were carried out with the same gas mixture and the same volume of water, as vapor, to observe the droplet formation and the corrosion process that follows. Effects of surface roughness on the droplet formation and its corrosion process were further studied and showed no significant role upon long time exposure. The results from droplet experiments were compared to those from the bulk electrolyte for the further recommendation on the quality control of gas stream along with the use of carbon steels as transport pipelines in CCS - Carbon Capture and Storage system. KW - CCUS, supercritical/dense phase CO2, carbon steels, martensitic steel, superaustenite steel, droplet corrosion PY - 2018 UR - http://corrosionjournal.com/doi/abs/10.5006/2927 U6 - https://doi.org/10.5006/2927 SN - 0010-9312 SN - 1938-159X VL - 74 IS - 12 SP - 1406 EP - 1420 PB - NACE International CY - Houston, Texas, USA AN - OPUS4-46903 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Donėlienė, J. A1 - Rudzikas, M. A1 - Rades, Steffi A1 - Dörfel, Ilona A1 - Peplinski, Burkhard A1 - Sahre, Mario A1 - Pellegrino, F. A1 - Maurino, V. A1 - Ulbikas, J. A1 - Galdikas, A. A1 - Hodoroaba, Vasile-Dan T1 - Electron Microscopy and X-Ray Diffraction Analysis of Titanium Oxide Nanoparticles Synthesized by Pulsed Laser Ablation in Liquid N2 - A femto-second pulsed laser ablation in liquid (PLAL) procedure for the generation of titanium oxide nanoparticles (NP) is reported with the purpose of understanding morphology and structure of the newly generated NPs. Ablation duration was varied for optimization of NP generation processes between 10 and 90 min. Surface morphology of NPs as well as their size and shape (distribution) were analysed by various complementary electron microscopy techniques, i.e. SEM, TSEM and TEM. The crystalline structure of titanium oxide particles was investigated by XRD(two instruments operated in different geometries) and HR-TEM. Concentration of generated titanium oxide NPs in liquid was analysed by ICP-MS. A mix of crystalline (mainly anatase), partly crystalline and amorphous spherical titanium oxide NPs can be reported having a mean size between 10 and 20 nm, which is rather independent of the laser ablation (LA) duration. A second component consisting of irregularly shaped, but crystalline titanium oxide nanostructures is co-generated in the LA water, with more pronounced occurrence at longer LA times. The provenance of this component is assigned to those spherical particles generated in suspension and passing through the converging laser beam, being hence subject to secondary irradiation effects, e. g. fragmentation. KW - Laser ablation in liquid KW - Nanoparticles KW - Titanium oxide KW - Particle morphology PY - 2018 UR - https://www.cambridge.org/core/journals/microscopy-and-microanalysis/article/electron-microscopy-and-xray-diffraction-analysis-of-titanium-oxide-nanoparticles-synthesized-by-pulsed-laser-ablation-in-liquid/AE368446FAC70E08C514F9AEABFD131B U6 - https://doi.org/10.1017/S1431927618009030 VL - 24 IS - S1 (August) SP - 1710 EP - 1711 PB - Cambridge University Press CY - New York, NY, U.S.A. AN - OPUS4-45949 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wollschläger, Nicole A1 - Nofz, Marianne A1 - Dörfel, Ilona A1 - Schulz, Wencke A1 - Sojref, Regine A1 - Kranzmann, Axel T1 - Exposition of sol-gel alumina-coated P92 steel to flue gas: Time-resolved microstructure evolution, defect tolerance, and repairing of the coating N2 - Technically relevant P92 steel (9% Cr) was coated with a micron-thick porous alumina layer prepared by sol-gel technique and treated with flue gas (60 CO2-30 H2O-2 O2-1 SO2-7 N2 (mole fraction in %)) at 650 ° to mimic an oxyfuelcombustion process. Local defects in the coating were marked using focused ion beam (FIB) technique and were inspected after exposition to hot flue gas atmosphere at 300, 800, and 1300 h, respectively. Local defects like agglomerated alumina sol particles tend to spall off from the coating uncovering the underlying dense chromia scale. Re-coating was found to restore the protection ability from oxidation when repeatedly treated with hot flue gas. Cracks and voids did not promote the local oxidation due to the formation of crystalline Mn/S/O species within and on top of the coating. The protective character of the steel-coating system is a result of (i) the fast formation of a dense chromia scale at the surface of sol-gel alumina-coated P92 steel bars in combination with (ii) the porous alumina coating acting as diffusion barrier, but also as diffusion partner in addition with (iii) fast Mn outward diffusion capturing the S species from flue gas. KW - Alumina coatings KW - Oxyfuel KW - Steel P92 KW - High temperature corrosion PY - 2018 U6 - https://doi.org/10.1002/maco.201709712 SN - 1521-4176 SN - 0947-5117 SN - 0043-2822 VL - 69 IS - 4 SP - 492 EP - 502 PB - Wiley-VCH Verlag GmbH&Co. KGaA CY - Weinheim AN - OPUS4-45300 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Paul, Andrea A1 - Wander, Lukas A1 - Becker, Roland A1 - Goedecke, Caroline A1 - Braun, Ulrike T1 - High-throughput NIR spectroscopic (NIRS) detection of microplastics in soil N2 - The increasing pollution of terrestrial and aquatic ecosystems with plastic debris leads to the accumulation of microscopic plastic particles of still unknown amount. To monitor the degree of contamination analytical methods are urgently needed, which help to quantify microplastics (MP). Currently, time-costly purified materials enriched on filters are investigated both by micro-infrared spectroscopy and/or micro-Raman. Although yielding precise results, these techniques are time consuming, and are restricted to the analysis of a small part of the sample in the order of few micrograms. To overcome these problems, here we tested a macroscopic dimensioned NIR process-spectroscopic method in combination with chemometrics. For calibration, artificial MP/soil mixtures containing defined ratios of polyethylene, polyethylene terephthalate, polypropylene, and polystyrene with diameters < 125 µm were prepared and measured by a process FT-NIR spectrometer equipped with a fiber optic reflection probe. The resulting spectra were processed by chemometric models including support vector machine regression (SVR), and partial least squares discriminant analysis (PLS-DA). Validation of models by MP mixtures, MP-free soils and real-world samples, e.g. and fermenter residue, suggest a reliable detection and a possible classification of MP at levels above 0.5 to 1.0 mass% depending on the polymer. The benefit of the combined NIRS chemometric approach lies in the rapid assessment whether soil contains MP, without any chemical pre-treatment. The method can be used with larger sample volumes and even allows for an online prediction and thus meets the demand of a high-throughput method. KW - Microplastics KW - Soil KW - Chemometrics KW - PLS-DA KW - Support vector machines KW - Near Infrared Spectroscopy PY - 2018 U6 - https://doi.org/10.1007/s11356-018-2180-2 SN - 1614-7499 SN - 0944-1344 VL - 26 IS - 8 SP - 7364 EP - 7374 PB - Springer AN - OPUS4-45405 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nützmann, Kathrin A1 - Wollschläger, Nicole A1 - Rockenhäuser, Christian A1 - Kranzmann, Axel A1 - Stephan-Scherb, Christiane T1 - Identification and 3D reconstruction of Cr5S6 precipitates along grain boundaries in Fe13Cr N2 - Metal sulfide grain boundary precipitates of a ferrous model alloy with 13 wt.% chromium formed at 650°C under a gas atmosphere containing 0.5% SO2 and 99.5% Ar were investigated after ageing for 3 h, 6 h, and 12 h. The precipitates formed along grain boundaries were identified as Cr5S6 using energy-dispersive x-ray spectroscopy in transmission electron microscopy and electron backscatter diffraction analysis. Serial focused ion beam slicing was conducted followed by three-dimensional reconstruction to determine the number, size, and penetration depth of the precipitates evolved at the different time steps. There was a linear increase in the number of precipitates with time, while their average size increased only for the initial aging time but became constant after 6 h. Based on these results, a model for grain boundary sulfidation of ferritic alloys is discussed. KW - Internal Sulfidation KW - Grain Boundary Corrosion KW - FIB Tomography PY - 2018 U6 - https://doi.org/10.1007/s11837-018-2940-y SN - 1047-4838 SN - 1543-1851 VL - 70 IS - 8 SP - 1478 EP - 1483 PB - Springer Science + Business Media CY - New York, NY AN - OPUS4-45090 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nolze, Gert A1 - Jürgens, Maria A1 - Olbricht, Jürgen A1 - Winkelmann, Aimo T1 - Improving the precision of orientation measurements from technical materials via EBSD pattern matching N2 - We use pattern matching of experimental and dynamically simulated backscattered Kikuchi diffraction (BKD) patterns to increase the orientation precision of electron backscatter diffraction (EBSD) measurements. In order to quantify the improvement in orientation precision, we analyze the experimental distribution of the kernel average misorientation (KAM) angles. We find that for the same raw data, i.e. the same EBSD data acquisition time budget, the pattern matching approach improves the KAM resolution by an order of magnitude compared to orientation data delivered from the conventional Hough-transform based data analysis. This quantitative improvement enables us to interpret small orientation changes in plastically deformed materials which are hidden in noisy orientation data delivered from the reference EBSD system. As an application example, we analyze a ferritic-martensitic steel (P92) sample before and after low-cycle fatigue (LCF) loading (±0.3% strain) at 620 °C. Whereas the low precision of the EBSD orientation data from the manufacturer software does not allow a reliable discrimination of the gradually changing microstructure, we find very clear systematic differences of the local microstructure after the pattern matching orientation refinement of the initial, raw pattern data. For the investigated P92 sample, the KAM-angle histograms are well described by two log-normal distributions indicating the already tempered and the remaining and mostly untempered martensite. KW - Misorientation KW - Thermo-mechanical loading KW - Martensite KW - Log-normal distribution KW - Bimodal distribution PY - 2018 U6 - https://doi.org/10.1016/j.actamat.2018.08.028 VL - 159 SP - 408 EP - 415 PB - Elsevier Ltd. AN - OPUS4-46454 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bresch, Sophie A1 - Mieller, Björn A1 - Delorme, F. A1 - Chen, C. A1 - Bektas, M. A1 - Moos, R. A1 - Rabe, Torsten T1 - Influence of Reaction-Sintering and Calcination Conditions on Thermoelectric Properties of Sm-doped Calcium Manganate CaMnO3 N2 - A wide range of solid-state synthesis routes for calcium manganate is reported in the literature, but there is no systematic study about the influence of the solid-state synthesis conditions on thermoelectric properties. Therefore, this study examined the influence of calcination temperature and calcination cycles on the Seebeck coefficient, electrical conductivity, and thermal conductivity. Higher calcination temperatures and repeated calcination cycles minimized the driving force for sintering of the synthesized powder, leading to smaller shrinkage and lower densities of the sintered specimens. As the electrical conductivity increased monotonously with increasing density, a higher energy input during calcination caused deterioration of electrical conductivity. Phase composition and Seebeck coefficient of sintered calcium manganate were not influenced by the calcination procedure. The highest thermoelectric properties with the highest power factors and figures of merit were obtained by means of reaction-sintering of uncalcined powder. KW - Thermoelectric oxides KW - Calcination KW - Solid-state-synthesis KW - Power factor KW - Reaction-sintering PY - 2018 U6 - https://doi.org/10.4416/JCST2018-00017 SN - 2190-9385 VL - 9 IS - 3 SP - 289 EP - 300 PB - Göller Verlag AN - OPUS4-46224 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nadammal, Naresh A1 - Kromm, Arne A1 - Saliwan Neumann, Romeo A1 - Farahbod, Lena A1 - Haberland, Christoph A1 - Portella, Pedro Dolabella T1 - Influence of support configurations on the characteristics of selective laser-melted Inconel 718 N2 - Samples fabricated using two different support configurations by following identical scan strategies during selective laser melting of superalloy Inconel 718 were characterized in this study. Characterization methods included optical microscopy, electron back-scattered diffraction and x-ray diffraction residual stress measurement. For the scan strategy considered, microstructure and residual stress development in the samples were influenced by the support structures. However, crystallographic texture intensity and the texture components formed within the core part of the samples were almost independent of the support. The formation of finer grains closer to the support as well as within the columnar grain boundaries resulted in randomization and texture intensity reduction by nearly half for the sample built on a lattice support. Heat transfer rates dictated by the support configurations in addition to the scan strategy influenced the microstructure and residual stress development in selective laser-melted Inconel 718 samples. KW - Additive manufacturing KW - Selective laser melting KW - Support configurations KW - Microstructure and texture KW - Residual stress PY - 2018 U6 - https://doi.org/10.1007/s11837-017-2703-1 SN - 1047-4838 SN - 1543-1851 VL - 70 IS - 3 SP - 343 EP - 348 PB - Springer CY - USA AN - OPUS4-44175 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bresch, Sophie A1 - Mieller, Björn A1 - Selleng, Christian A1 - Stöcker, T. A1 - Moos, R. A1 - Rabe, Torsten T1 - Influence of the calcination procedure on the thermoelectric properties of calcium cobaltite Ca3Co4O9 N2 - Calcium cobaltite is one of the most promising oxide p-type thermoelectric materials. The solid-state reaction (or calcination, respectively), which is well known for large-scale powder synthesis of functional materials, can also be used for the synthesis of thermoelectric oxides. There are various calcination routines in literature for Ca3Co4O9 powder synthesis, but no systematic study has been done on the influence of calcination procedure on thermoelectric properties. Therefore, the influence of calcination conditions on the Seebeck coefficient and the electrical conductivity was studied by modifying calcination temperature, dwell time, particle size of raw materials and number of calcination cycles. This study shows that elevated temperatures, longer dwell times, or repeated calcinations during powder synthesis do not improve but deteriorate the thermoelectric properties of calcium cobaltite. Diffusion during calcination leads to idiomorphic grain growth, which lowers the driving force for sintering of the calcined powder. A lower driving force for sintering reduces the densification. The electrical conductivity increases linearly with densification. The calcination procedure barely influences the Seebeck coefficient. The calcination procedure has no influence on the phase formation of the sintered specimens. KW - Thermoelectrics KW - Calcination KW - Calcium Cobaltite KW - Solid-State-Synthesis KW - Reaction-sintering PY - 2018 U6 - https://doi.org/10.1007/s10832-018-0124-3 SN - 1385-3449 SN - 1573-8663 VL - 40 IS - 3 SP - 225 EP - 234 PB - Springer AN - OPUS4-44336 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stegemann, Robert A1 - Cabeza, Sandra A1 - Pelkner, Matthias A1 - Lyamkin, Viktor A1 - Pittner, Andreas A1 - Werner, Daniel A1 - Wimpory, R. A1 - Boin, M. A1 - Kreutzbruck, Marc A1 - Bruno, Giovanni T1 - Influence of the microstructure on magnetic stray fields of low-carbon steel welds N2 - This study examines the relationship between the magnetic mesostructure with the microstructure of low carbon steel tungsten inert gas welds. Optical microscopy revealed variation in the microstructure of the parent material, in the heat affected and fusion zones, correlating with distinctive changes in the local magnetic stray fields measured with high spatial resolution giant magneto resistance sensors. In the vicinity of the heat affected zone high residual stresses were found using neutron diffraction. Notably, the gradients of von Mises stress and triaxial magnetic stray field modulus follow the same tendency transverse to the weld. In contrast, micro-X-ray fluorescence characterization indicated that local changes in element composition had no independent effect on magnetic stray fields. KW - TIG-welding KW - GMR sensors KW - Magnetic stray field KW - Neutron diffraction KW - Residual stress KW - Microstructure KW - Low carbon steel PY - 2018 U6 - https://doi.org/10.1007/s10921-018-0522-0 SN - 0195-9298 SN - 1573-4862 VL - 37 IS - 3 SP - 66,1 EP - 18 PB - Springer US CY - New York AN - OPUS4-45855 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Epishin, A. A1 - Chyrkin, A. A1 - Nolze, Gert A1 - Midtlyng, Jan A1 - Mayer, H. M. A1 - Petrushin, N. A1 - Reimers, W. T1 - Interdiffusion in the Face-Centered Cubic Phase of the Co-Al-W-Ta System Between 1090 and 1240 °C N2 - Interdiffusion of Al, W, Ta and Co in a Co-base alloy at temperatures between 1090 and 1240 °C has been investigated. The interdiffusion coefficients were found to be close to those reported for these elements in Ni-base alloys. Combining the diffusion simulation software DICTRA with the Ni-base diffusion databases TCNi5 and MobNi3, the interdiffusion profiles of Co, Al W, and Ta were modeled for Co9Al8W2Ta/Co diffusion couples annealed at different temperatures and for different times. The results show that interdiffusion in the Co-Al-W-Ta alloys can be modeled reasonably well using the available commercial databases for thermodynamics and kinetics of Ni-base systems. KW - Alloys KW - Interdiffusion KW - Modeling PY - 2018 U6 - https://doi.org/10.1007/s11669-018-0620-9 VL - 39 IS - 2 SP - 176 EP - 185 PB - Springer AN - OPUS4-44463 LA - eng 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 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-460918 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 - JOUR A1 - Epishin, A. A1 - Petrushin, N. A1 - Gerstein, G. A1 - Maier, J. A1 - Nolze, Gert T1 - Investigation of the gamma'-strengthened quaternary co-based alloys Co-Al-W-Ta N2 - The alloying system Co-Al-W-Ta is comprehensively investigated in the vicinity of the compositional point Co-9Al-10W-2Ta, at. pct. These investigations provided a large amount of quantitative information, which can be used for alloy development, namely, the compositional dependences of the The alloying system Co-Al-W-Ta is comprehensively investigated in the vicinity of the compositional point Co-9Al-10W-2Ta, at. pct. These investigations provided a large amount of quantitative information, which can be used for alloy development, namely, the compositional dependences of the γ‘-solvus, solidus, and liquidus temperatures; fraction of the extrinsic phases after casting; the compositional dependence of the γ/γ‘-lattice misfit; the element partitioning between γ- and γ‘-phases; and the two Phase compositional area γ/γ‘ in the Co-rich part of the Co-Al-W-Ta phase diagram at 900°C. It is shown that additions of Ta elevate the γ‘-solvus temperature and increase the γ/γ‘-lattice misfit, but adding more than about 3 at. pct Ta results in a large amount of undissolvable extrinsic phases. Additionally, two Co-Al-W-Ta alloys with lower content of W were developed and solidified as [001] single crystals for mechanical testing in a temperature range between 20 and 1200°C. These tests included measurement of the Young modulus, tensile tests with constant strain rate, and stress rupture tests. It was found that at temperatures up to about 750°C the ultimate tensile strength of Co-Al-Ta-W alloys can be at the same level or even higher than of Ni-based superalloys. KW - Cobald based alloy KW - Microstructur KW - Segregation PY - 2018 U6 - https://doi.org/10.1007/s11661-018-4756-3 SN - 1543-1940 SN - 1073-5623 VL - 49A IS - 9 SP - 4042 EP - 4057 PB - Springer Sciences & Business Media CY - New York, NY AN - OPUS4-45395 LA - eng 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 U6 - 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 U6 - 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 - 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 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-459803 UR - https://rdcu.be/7aPD 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 - JOUR A1 - Prasetiadi, A. E. A1 - Jost, M. A1 - Schulz, Baerbel A1 - Quibeldey, M. A1 - Rabe, Torsten A1 - Follmann, R. A1 - Jakoby, R. T1 - Liquid-crystal-based amplitude tuner and tunable SIW filter fabricated in LTCC technology N2 - Tunable microwave devices will play an important role in future wireless systems, in which high-frequency bands, e.g. millimeter waves, will become promising, due to its huge spectrum availability. At such frequency bands, liquid crystals (LCs) exhibit low microwave loss, which is excellent compared with the other tuning elements. In this paper, LC-based microwave components are fabricated by using low temperature co-fired ceramic technology, allowing the integration of the LC into microwave structures. The first component, the Amplitude tuner, controls the signal’s amplitude by using the interference concept, which exhibits a tunable attenuation range from 11 dB to 30 dB at 30 GHz. The second component is a 3-pole tunable bandpass filter, which is realized by using a substrate integrated waveguide topology, enabling a device with comparatively high-quality factors (Q-factors). The measurement results show Q-factors in the range of 68 to 100 for a frequency tuning of 29.4–30.1 GHz, i.e. a tuning range of 700 MHz, accompanied by an insertion loss 2 dB to 4 dB. KW - Passive components and circuits KW - Filters KW - Microwave technology PY - 2018 U6 - https://doi.org/10.1017/S1759078718000600 SN - 1759-0787 VL - 10 IS - 5-6 SP - 674 EP - 681 PB - Cambridge University Press AN - OPUS4-46985 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pfennig, Anja A1 - Kranzmann, Axel T1 - Local Corrosion of Martensitic Stainless Steels during Exposure to Saline Aquifer Water and CO2 Environment N2 - Carbon Capture and Storage (CCS) is well acknowledged to mitigate climate change. Therefore, pipe Steels suitable for CCS technology require resistance against the corrosive environment of a potential CCS-site, e.g. heat, pressure, salinity of the aquifer, CO2-partial pressure. Samples of different mild and high alloyed stainless injection-pipe Steels partially heat treated: 42CrMo4, X20Cr13, X46Cr13, X35CrMo4 as well as X5CrNiCuNb16-4 were kept at T=60 °C and ambient pressure as well as p=100 bar for 700 h - 8000 h in a CO2-saturated synthetic aquifer environment similar to possible geological on-shore CCS-sites in the northern German Basin. Main corrosion products analysed on pits are FeCO3 and FeOOH. The carbon content does not show significant influence on the pitting behaviour. Generally, higher chromium Content results in better corrosion resistance. Although X35CrMo17-1 and X5CrNiCuNb16-4 show low surface corrosion rates, their resistance against local corrosion in CCS environment is not significantly better compared to the much less costly Steels X20Cr13 and X46Cr13. KW - Corrosion KW - CCS KW - Carbon storage KW - Aquifer KW - Heat treatment PY - 2018 U6 - https://doi.org/10.18178/ijcea.2018.9.1.694 SN - 2010-0221 VL - 9 SP - 26 EP - 31 PB - International Association of Computer Science and Information Technology Press CY - Singapore AN - OPUS4-46627 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 U6 - 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 - 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 U6 - 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 - JOUR A1 - Winkelmann, A. A1 - Nolze, Gert A1 - Cios, G. A1 - Tokarski, T. T1 - Mapping of local lattice parameter ratios by projective Kikuchi pattern matching N2 - We describe a lattice-based crystallographic approximation for the analysis of distorted crystal structures via Electron Backscatter Diffraction (EBSD) in the scanning electron microscope. EBSD patterns are closely linked to local lattice parameter ratios via Kikuchi bands that indicate geometrical lattice plane projections. Based on the transformation properties of points and lines in the real projective plane, we can obtain continuous estimations of the local lattice distortion based on projectively transformed Kikuchi diffraction simulations for a reference structure. By quantitative image matching to a projective transformation model of the lattice distortion in the full solid angle of possible scattering directions, we enforce a crystallographically consistent approximation in the fitting procedure of distorted simulations to the experimentally observed diffraction patterns. As an application example, we map the locally varying tetragonality in martensite grains of steel. KW - EBSD KW - Scanning electron microscopy KW - Orientation refinement PY - 2018 U6 - https://doi.org/10.1103/PhysRevMaterials.2.123803 SN - 2475-9953 VL - 2 IS - 12 SP - 123803, 1 EP - 15 PB - American Physical Society CY - College Park, MD AN - OPUS4-47296 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Blaeß, Carsten A1 - Müller, Ralf T1 - Master curve for viscous crack healing N2 - A novel method to generalize kinetic data of viscous crack healing in glasses is proposed. The method assumes that crack healing progress is proportional to the healing time, t, and indirect proportional to viscosity, n. This way, crack length and crack width data, normalized to the initial crack length and plotted versus t/n, allow to compare crack healing progress for different cracks and healing temperatures in a master curve. Crack healing experiments conducted in this study demonstrate the applicability of this method for a commercial microscope slide glass. KW - Crack healing KW - Glass KW - Master curve KW - Vickers indentation PY - 2018 U6 - https://doi.org/10.1016/j.matlet.2017.12.082 SN - 0167-577X SN - 1873-4979 VL - 216 SP - 110 EP - 112 PB - Elsevier AN - OPUS4-44300 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Böllinghaus, Thomas A1 - Lüders, V. A1 - Nolze, Gert T1 - Microstructural insights into natural silver wires N2 - Due to the increasing global demand for pure silver, native wire silver aggregates in very high purities are gaining more industrial attention. Up to the present, no substantial metallurgical Investigation of natural wire silver exists in the accessible literature. To convey urgently needed cross-disciplinary fundamental knowledge for geoscientists and metallurgical engineers, twenty natural wire silver specimens from eight different ore deposits have been investigated in detail for the first time by EBSD (Electron Back Scattering Diffraction), supported by light microscopy and micro-probe analyses. The improved understanding of the natural silver wire microstructure provides additional Information regarding the growth of natural silver aggregates in comparison to undesired artificial growth on electronic devices. Clear evidence is provided that natural silver curls and hairs exhibit a polycrystalline face-centered cubic microstructure associated with significant twinning. Although the investigated natural wire silver samples have relatively high purity (Ag > 99.7 wt.-%), they contain a variety of trace elements such as, S, Cu, Mn, Ni, Zn, Co and Bi, As and Sb. Additionally, Vickers micro-hardness measurements are provided for the first time which revealed that natural silver wires and curls are softer than it might be expected from conversion of the general Mohs hardness of 2.7. KW - Natural silver wires PY - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-451655 UR - http://www.nature.com/articles/s41598-018-27159-w SN - 2045-2322 VL - 8 IS - 1 SP - Article 9053, 1 EP - 9 PB - nature publishing group CY - London, United Kingdom AN - OPUS4-45165 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dmitriev, A. I. A1 - Nikonov, A. Y. A1 - Österle, Werner T1 - Molecular dynamics modeling of the sliding performance of an amorphous silica nano-layer - The impact of chosen interatomic potentials N2 - The sliding behavior of an amorphous silica sample between two rigid surfaces is in the focus of the present paper. Molecular Dynamics using a classical Tersoff’s potential and a recently developed ReaxFF potential was applied for simulating sliding within a thin film corresponding to a tribofilm formed from silica nanoparticles. The simulations were performed at different temperatures corresponding to moderate and severe tribological stressing conditions. Simulations with both potentials revealed the need of considering different temperatures in order to obtain a sound interpretation of experimental findings. The results show the striking differences between the two potentials not only in terms of magnitude of the resistance stress (about one order of magnitude) but also in terms of friction mechanisms. The expected smooth sliding regime under high temperature conditions was predicted by both simulations, although with Tersoff’s potential smooth sliding was obtained only at the highest temperature. On the other hand, at room temperature Tersoff-style calculations demonstrate stick-slip behavior, which corresponds qualitatively with our experimental findings. Nevertheless, comparison with a macroscopic coefficient of friction is not possible because simulated resistance stresses do not depend on the applied normal pressure. KW - Molecular dynamics KW - Thin tribofilm KW - Resistance stress KW - Sliding simulation KW - Amorphous silica PY - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-449366 SN - 2075-4442 VL - 6 IS - 2 SP - 43, 1 EP - 11 PB - MDPI CY - Basel AN - OPUS4-44936 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Martin-Sanchez, Pedro Maria A1 - Gebhardt, Christopher A1 - Toepel, Jörg A1 - Barry, J. A1 - Munzke, N. A1 - Günster, Jens A1 - Gorbushina, Anna T1 - Monitoring microbial soiling in photovoltaic systems: A qPCR-based approach N2 - Soiling of photovoltaic (PV) systems compromises their performance causing a significant power loss and demanding periodical cleaning actions. This phenomenon raises great concerns in the solar energy field, thus leading to notable research efforts over the last decades. Soiling is caused by a dual action of dust deposition and biofouling. However, surprisingly, the microbiological contribution to PV soiling is often overlooked or underestimated. In this study, a variety of qPCR-based methods have been developed to quantify the microbial load of fungi, bacteria and phototrophs on PV panels. These protocols were evaluated by comparison with culturedependent methods, and were implemented with real solar plants for two years. The results show that the developed molecular methods are highly sensitive and reliable to monitor the microbial component of the soiling. Fungal biomass was clearly dominant in all analysed PV modules, while bacteria and phototrophs showed much lower abundance. Light microscopy and qPCR results revealed that melanised microcolonial fungi and phototrophs are the main biofilm-forming microorganisms on the studied solar panels. In particular, the fungal qPCR protocol is proposed as a useful tool for monitoring of PV soiling, and investigating the microbial contribution to specific soiling cases. KW - Solar panels KW - PV modules KW - Real-time qPCR KW - Bacteria KW - Fungi KW - Phototrophs PY - 2018 U6 - https://doi.org/10.1016/j.ibiod.2017.12.008 SN - 0964-8305 VL - 129 SP - 13 EP - 22 PB - Elsevier Science AN - OPUS4-43892 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mair, Georg A1 - Becker, B. A1 - Gesell, Stephan A1 - Wang, Bin T1 - Monte-Carlo-analysis of minimum load cycle requirements for composite cylinders for hydrogen N2 - Hydrogen is an attractive energy carrier that requires high effort for safe storage. For ensuring safety, storage cylinders must undergo a challenging approval process. Relevant standards and regulations for composite cylinders used for the transport of hydrogen and for its onboard storage are currently based on deterministic (e.g. ISO 11119-3) or to some respect semi-probabilistic criteria (UN GTR No. 13; with respect to burst strength). This paper provides a systematic analysis of the load cycle properties resulting from these regulations and standards. Their characteristics are compared with the probabilistic approach of the Federal Institute for Materials Research and Testing BAM. The most important aspect of comparing different concepts is the rate for accepting designs with potentially unsafe or critical safety properties. This acceptance rate is analysed by operating Monte-Carlo simulations over the available range of production properties. T2 - ICHS 2017 CY - Hamburg, Germany DA - 11.09.2017 KW - Safety assessment KW - Failure rate KW - Ageing KW - Degradation KW - End of life KW - Production scatter PY - 2018 U6 - https://doi.org/10.1016/j.ijhydene.2018.09.185 SN - 0360-3199 VL - 44 IS - 17 SP - 8833 EP - 8841 PB - Elsevier Ltd AN - OPUS4-46341 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Donėlienė, J. A1 - Rudzikas, M. A1 - Rades, Steffi A1 - Dörfel, Ilona A1 - Peplinski, Burkhard A1 - Sahre, Mario A1 - Pellegrino, F. A1 - Maurino, V. A1 - Ulbikas, J. A1 - Galdikas, A. A1 - Hodoroaba, Vasile-Dan T1 - Morphology and structure of TixOy nanoparticles generated by femtosecond laser ablation in water N2 - In this work femto-second pulsed laser ablation in liquid (PLAL) procedure for the generation of titanium oxide nanoparticles (NP) is reported with the purpose of understanding morphology and structure of the newly generated NPs. Ablation duration was varied for optimization of NP generation processes between 10 and 90 min. Surface morphology of NPs as well as their size and shape (distribution) were analysed by various complementary electron microscopy techniques, i.e. SEM, TSEM and TEM. The crystalline structure of titanium oxide particles was investigated byXRD(two instruments operated in different geometries) and HR-TEM. Concentration of generated titanium oxide NPs in liquid was analysed by ICP-MS. A mix of crystalline (mainly anatase), partly crystalline and amorphous spherical titanium oxide NPs can be reported having a mean size between 10 and 20 nm, which is rather independent of the laser ablation (LA) duration. A second component consisting of irregularly shaped, but crystalline titanium oxide nanostructures is co-generated in the LA water, with more pronounced occurrence at longer LA times. The provenance of this component is assigned to those spherical particles generated in suspension and passing through the converging laser beam, being hence subject to secondary irradiation effects, e. g. fragmentation. KW - Titanium oxide KW - Nanoparticles KW - Laser ablation in liquid KW - Particle morphology KW - Nanoparticle structure PY - 2018 U6 - https://doi.org/10.1088/2053-1591/aaba56 SN - 2053-1591 VL - 5 IS - 4 SP - 045015-1 EP - 045015-12 PB - IOP Publishing CY - London, UK AN - OPUS4-44678 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Usmani, Shirin A1 - Stephan, Ina A1 - Huebert, Thomas A1 - Kemnitz, E. T1 - Nano metal fluorides for wood protection against fungi N2 - Wood treated with nano metal fluorides is found to resist fungal decay. Sol−gel synthesis was used to synthesize MgF2 and CaF2 nanoparticles. Electron microscopy images confirmed the localization of MgF2 and CaF2 nanoparticles in wood. Efficacy of nano metal fluoride-treated wood was tested against brown-rot fungi Coniophora puteana and Rhodonia placenta. Untreated wood specimens had higher mass losses (∼30%) compared to treated specimens, which had average mass loss of 2% against C. puteana and 14% against R. placenta, respectively. Nano metal fluorides provide a viable alternative to current wood preservatives. KW - Brown-rot fungi KW - Coniophora puteana KW - Fluoride nanoparticles KW - Fluorolytic sol−gel KW - Rhodonia placenta KW - SEM wood characterization KW - Wood protection PY - 2018 U6 - https://doi.org/10.1021/acsanm.8b00144 SN - 2574-0970 VL - 2018 SP - 1 EP - 6 PB - American Chemical Society (ACS) CY - Washington DC, US AN - OPUS4-44730 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 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-451417 UR - http://zoobank.org/5C7DBB2B-B27D-4CE6-9656-33C4A0DA0F39 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 - JOUR A1 - Eh Hovsepian, P. A1 - Ehiasarian, A. P. A1 - Purandare, Y. P. A1 - Mayr, P. A1 - Abstoss, K. G. A1 - Mosquera Feijoo, Maria A1 - Schulz, Wencke A1 - Kranzmann, Axel A1 - Lasanta, M. I. A1 - Trujillo, J. P. T1 - Novel HIPIMS deposited nanostructured CrN/NbN coatings for environmental protection of steam turbine components N2 - To increase efficiency, modern steam plants are pushing their operational regime from super-critical (600 °C/300 bar) to ultra-super-critical (740/760 °C/350 bar) stretching existing turbine materials to their limits. The focus is on new generation functional materials and technologies which complement the inherent properties of existing materials. Current work proposes a novel High Power Impulse Magnetron Sputtering (HIPIMS) Deposition technology, for the first time, for deposition of a ceramic based CrN/NbN coating with a nanoscale multilayer structure (bi-layer thickness Δ = 1.9 nm) with superior adhesion (LC2 = 80 N) to protect low Chromium P92 steel widely used in steam power plants. Thermodynamic calculations predict the equilibrium phases and aggressive gaseous compounds generated by the interaction of steam with the coating. CrN/NbN coated P92 steel samples oxidised at 600 °C in a high pressure (50 bar) 100% steam atmosphere for up to 1000 h reveal the coating's superior oxidation resistance and protective mechanisms, especially against the detrimental effect of Hydrogen. High temperature (650 °C) Tensile Strength, Low Cycle Fatigue and Creep tests confirm that, unlike other state-of-the-art PVD technologies, HIPIMS is not detrimental to the mechanical properties of the substrate material. Water droplet erosion tests confirm no measurable weight loss after 2.4 X 10⁶ impacts. KW - Hipims KW - CrN/NbN KW - Nanoscale multilayers KW - Steam oxidation resistance KW - Water droplet erosion resistance PY - 2018 U6 - https://doi.org/10.1016/j.jallcom.2018.02.312 SN - 0925-8388 SN - 1873-4669 VL - 746 SP - 583 EP - 593 PB - Elsevier AN - OPUS4-44800 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Eggeler, G. A1 - Wieczorek, N. A1 - Fox, F. A1 - Berglund, S. A1 - Bürger, D. A1 - Dlouhý, A. A1 - Wollgramm, P. A1 - Neuking, K. A1 - Schreuer, J. A1 - Agudo Jácome, Leonardo A1 - Gao, S. A1 - Hartmaier, A. A1 - Laplanche, G. T1 - On shear testing of single crystal Ni-base superalloys N2 - Shear testing can contribute to a better understanding of the plastic deformation of Ni-base superalloy single crystals. In the present study, shear testing is discussed with special emphasis placed on its strengths and weaknesses. Key mechanical and microstructural results which were obtained for the high-temperature (T ≈ 1000 °C) and low-stress (τ ≈ 200 MPa) creep regime are briefly reviewed. New 3D stereo STEM images of dislocation substructures which form during shear creep deformation in this regime are presented. It is then shown which new aspects need to be considered when performing double shear creep testing at lower temperatures (T < 800 °C) and higher stresses (τ > 600 MPa). In this creep regime, the macroscopic crystallographic [11−2](111) shear system deforms significantly faster than the [01−1](111) system. This represents direct mechanical evidence for a new planar fault nucleation scenario, which was recently suggested (Wu et al. in Acta Mater 144:642–655, 2018). The double shear creep specimen geometry inspired a micro-mechanical in-situ shear test specimen. Moreover, the in-situ SEM shear specimen can be FIB micro-machined from prior dendritic and interdendritic regions. Dendritic regions, which have a lower γ′ volume fraction, show a lower critical resolved shear stress. T2 - EuroSuperalloys 2018 CY - Oxford, UK DA - 09.09.2018 KW - Superalloy single crystals KW - Shear testing KW - Creep mechanisms KW - In-situ SEM micro shear deformation KW - Transmission electron microscopy PY - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-456591 SN - 1073-5623 SN - 1543-1940 VL - 49A IS - 9 SP - 3951 EP - 3962 PB - Springer US CY - New York AN - OPUS4-45659 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 U6 - 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 - JOUR A1 - Prewitz, M. A1 - Gaber, M. A1 - Müller, Ralf A1 - Marotzke, C. A1 - Holtappels, Kai T1 - Polymer coated glass capillaries and structures for high-pressure hydrogen storage: Permeability and hydrogen tightness N2 - The hydrogen tightness of high-pressure hydrogen storage is a Basic criterion for long-term storage. The H2 permeation coefficients of epoxy resin and a glass lacquer were determined to enable the geometric optimization of a glass capillary storage. It was found that the curing conditions have no significant influence on the H2 permeation coefficient of resin. The H2 permeation coefficient of epoxy resin is only about three orders of Magnitude greater than that of borosilicate glass. This suggests that the initial pressure of 700 bar takes about 2.5 years to be halved in capillary array storage. Therefore, a high-pressure hydrogen storage tank based on glass capillaries is ideally suited for long-term storage in mobile applications. KW - Permeability KW - Glass capillaries KW - Coating KW - Hydrogen storage KW - Long-term calculation KW - Epoxy resin PY - 2018 U6 - https://doi.org/10.1016/j.ijhydene.2017.12.092 SN - 0360-3199 VL - 43 IS - 11 SP - 5637 EP - 5644 PB - Elsevier AN - OPUS4-44327 LA - eng 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 U6 - 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 - JOUR A1 - Stephan-Scherb, Christiane A1 - Nützmann, Kathrin A1 - Kranzmann, Axel A1 - Klaus, M. A1 - Genzel, C. T1 - Real time observation of high temperature oxidation and sulfidation of Fe-Cr model alloys N2 - Insights into early damage mechanisms during high-temperature gas corrosion provide important aspects for the prediction of the long-term stability of hightemperature materials exposed to a hot and corrosive environment. The current work presents a real time study concerning the combined oxidation and sulfidation of ferritic model alloys in a hot SO2 containing atmosphere using energy dispersive X-ray diffraction. The applied high temperature reactor allows the transmittance of high energetic X-rays in order to collect X-ray diffraction pattern of the sample surface in situ during the reaction with the reactive environment. The results revealed that the first phases crystallizing on iron with 2 wt% chromium and with 9 wt% chromium are oxides. The aging experiments at T = 650° C with 0.5% SO2 and 99.5% Ar were followed in situ and caused an external mixed oxide-sulfide layer on top of iron with 2 wt% chromium. On the higher alloyed material the external scale consists of iron oxides and the inner scale of mixed (Fe,Cr)-oxides and chromium-sulfides. The oxide content continuously increases parallel to an increase of the sulfide amount. Thus, the initially formed (Fe,Cr)-oxides do not have a protective character and support the transport of sulfur through the growing oxide scale. KW - High temperature corrosion KW - In situ diffraction KW - Sulfidation PY - 2018 U6 - https://doi.org/10.1002/maco.201709892 SN - 0947-5117 VL - 69 IS - 6 SP - 678 EP - 689 PB - Wiley VCH Verlag AN - OPUS4-44776 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Thiede, Tobias A1 - Cabeza, S. A1 - Mishurova, Tatiana A1 - Nadammal, N. A1 - Kromm, Arne A1 - Bode, Johannes A1 - Haberland, C. A1 - Bruno, Giovanni T1 - Residual stress in selective laser melted Inconel 718: Influence of the removal from base plate and deposition hatch length N2 - The residual stress distribution in IN718 elongated prisms produced by Selective Laser Melting was studied by means of neutron (bulk) and laboratory X-ray (surface) diffraction. Two deposition hatch lengths were considered. A horizontal plane near the top surface (perpendicular to the building direction) and a vertical plane near the lateral surface (parallel to the building direction) were investigated. Samples both in as-built (AB) condition and removed (RE) from the base plate were characterized. While surface stress fields seem constant for AB condition, X-ray diffraction shows stress gradients along the hatch direction in the RE condition. The stress profiles correlate with the distortion maps obtained by tactile probe measurements. Neutron diffraction shows bulk stress gradients for all principal components along the main sample directions. We correlate the observed stress patterns with the hatch length, i.e. with its effect on temperature gradients and heat flow. The bulk stress gradients partially disappear after removal from the baseplate. KW - Residual stress KW - Additive manufacturing KW - Neutron diffraction KW - Selective laser melting KW - Laboratory X-ray diffraction KW - Coordinate measurement machine KW - IN718 PY - 2018 U6 - https://doi.org/10.1520/MPC20170119 SN - 2379-1365 VL - 7 IS - 4 SP - 717 EP - 735 PB - ASTM International CY - USA, West Conshohocken AN - OPUS4-46673 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 U6 - 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 - Schulz, T. A1 - Reimann, T. A1 - Bochmann, A. A1 - Vogel, A. A1 - Capraro, B. A1 - Mieller, Björn A1 - Teichert, S. A1 - Töpfer, J. T1 - Sintering behavior, microstructure and thermoelectric properties of calcium cobaltite thickfilms for transversal thermoelectric multilayer generators N2 - The sintering behavior and the thermoelectric performance of Ca3Co4O9 multilayer laminates were studied, and a multilayer thermoelectric generator was fabricated. Compacts and multilayer samples with anisotropic microstructure and residual porosity were obtained after conventional sintering at 920 °C, whereas dense and isotropic multilayer samples were prepared by firing at 1200 °C and reoxidation at 900 °C. A hot-pressed sample has a dense and anisotropic microstructure. Samples sintered at 920 °C exhibit low electrical conductivity due to the low density, whereas the Seebeck coefficient is not sensitive to preparation conditions. However, thermal conductivity of multilayers is very low, and, hence acceptable ZT values are obtained. A ransversal multilayer thermoelectric generator (TMLTEG) was fabricated by stacking layers of Ca3Co4O9 green tapes, AgPd conductor printing, and co-firing at 920 °C. The TMLTEG has a power output of 3 mW at ΔT =200 K in the temperature interval of 25 °C to 300 °C. KW - Thermoelectric oxide KW - Calcium cobaltite KW - Pressure-assisted sintering KW - Multilayer PY - 2018 U6 - https://doi.org/10.1016/j.jeurceramsoc.2017.11.017 SN - 0955-2219 SN - 1873-619X VL - 38 IS - 4 SP - 1600 EP - 1607 PB - Elsevier Ltd. AN - OPUS4-43983 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Höhne, Patrick A1 - Mieller, Björn A1 - Rabe, Torsten T1 - Slurry development for spray granulation of ceramic multicomponent batches N2 - The granules commonly yielded by spray drying procedures exhibit a hard shell and an irregular, dimpled shape, which is often described as donut-like morphology. Sintered parts produced from such granules suffer from microstructural defects and reduced mechanical properties resulting from these disadvantageous granule properties. Using the example of alumina, zirconia and zirconia-toughened alumina (ZTA) batches, this paper shows that the morphology of the granules can be tuned by adjusting slurry stability. High zeta potential is essential to optimally disperse the particles. But to achieve spherical and soft granules the electrostatic repulsion forces between the particles should be reduced before spray granulation. Electrostatic repulsion forces were changed with the addition of nitric acid. Measurements of zeta potential and viscosity, as well as sedimentation investigations with an optical centrifuge were used for precise slurry assessment as a major precondition for optimal and reproducible adjustment of slurries before spray drying. Sedimentation analysis using an optical centrifuge was performed to investigate different influences like that of additive composition, solids content or pH-value on the sedimentation behavior. Adequately flocculated slurries lead to homogeneous, soft granules that can be easily deformed and pressed. The fraction of donut-shaped particles and the rigidity of granules were reduced. Consequently, the sintered parts produced from these granulates show improvements regarding porosity, pore size distribution, sintered density and biaxial strength. KW - Slurry optimization KW - Optical centrifugation KW - Destabilization KW - Spray drying KW - Biaxial strength PY - 2018 U6 - https://doi.org/10.4416/JCST2018-00022 SN - 2190-9385 VL - 9 IS - 3 SP - 327 EP - 336 PB - Göller Verlag AN - OPUS4-46225 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 U6 - 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 - JOUR A1 - Mujica Roncery, L. A1 - Agudo Jácome, Leonardo A1 - Aghajani, A. A1 - Theisen, W. A1 - Weber, S. T1 - Subsurface characterization of high-strength high-interstitial austenitic steels after impact wear N2 - The microstructure of the subsurface after impact wear of three high-strength high interstitial austenitic steels has been analysed using transmission electron microscopy (TEM) in alloys with C and N as interstitial elements. In all cases, a nanocrystalline region followed by a transition zone and a cold-worked area are present. Additionally, microhardness and nano-scratching tests were conducted to study the wear-related properties of the impact subsurface and the base material. The results of the microstructural analysis reveal that the following mechanisms are involved during impact wear: abrasion (ploughing), microcrack formation associated with contact fatigue, entrapment and adhesion of SiO2 particles. The analysis of the wear-related properties indicates that the subsurface acts as a self-protective layer that prevents the deterioration of the substrate. KW - Impact wear KW - TEM KW - Nano-scratch test KW - High interstitial austenitic steel PY - 2018 U6 - https://doi.org/10.1016/j.wear.2018.02.016 SN - 0043-1648 VL - 402-403 SP - 137 EP - 147 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-44290 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kalinka, Gerhard A1 - Sahin, M. A1 - Schlögl, S. A1 - Wang, J. A1 - Kaynak, B. A1 - Mühlbacher, I. A1 - Ziegler, W. A1 - Kern, W. A1 - Grützmacher, H. T1 - Tailoring the interfaces in glass fiber-reinforced photopolymer composites N2 - The present work provides a comparative study on the interface and adhesion properties of surface modified single glass fibers embedded in an acrylate matrix. To facilitate a covalent bonding at the fibermatrix interface, the fibers are functionalized with selected organosilanes that comprise either passive (unsaturated C¼C bonds of methacrylate moieties) or photoactive functionalities (photocleavable bis(acyl)phosphane oxide groups). Immobilization of the functional silanes is carried out by a classic silanization reaction involving a condensation reaction across the surface hydroxyl groups of the inorganic glass fibers. The change of the physico-chemical properties of the fibers due to desizing and subsequent surface modification is monitored by X-ray photoelectron spectroscopy and zeta potential measurements. In addition, scanning electron microscopy is used to follow the changes in surface morphology. After the modification step, the desized and modified single fibers are embedded in a photocurable acrylate resin formulation. By performing single fiber pull-out tests, maximum pull-out force, friction strength and apparent interfacial shear strength are determined as a function of the coupled silanes. The results reveal that the attached organosilanes lead to a significant increase in adhesion strength, whilst the performance of the photo-cleavable organosilane is superior to the passive methacryl-functional derivative. KW - Photocleavable organosilanes KW - Fiber-matrix interface KW - Photopolymer composites KW - Single fiber pull-out test KW - Surface modification PY - 2018 U6 - https://doi.org/10.1016/j.polymer.2018.03.020 SN - 0032-3861 VL - 141 SP - 221 EP - 231 PB - Elsevier Ltd. CY - New York AN - OPUS4-44784 LA - eng 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 U6 - 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 - JOUR A1 - Mueller, Axel A1 - Becker, Roland A1 - Dorgerloh, Ute A1 - Simon, Franz-Georg A1 - Braun, Ulrike T1 - The effect of polymer aging on the uptake of fuel aromatics and ethers by microplastics N2 - Microplastics are increasingly entering marine, limnic and terrestrial ecosystems worldwide, where they sorb hydrophobic organic contaminants. Here, the sorption behavior of the fuel-related water contaminants benzene, toluene, ethyl benzene and xylene (BTEX) and four tertiary butyl ethers to virgin and via UV radiation aged polypropylene (PP) and polystyrene (PS) pellets was investigated. Changes in material properties due to aging were recorded using appropriate polymer characterization methods, such as differential scanning calorimetry, Fourier transform infrared spectroscopy, gel permeation chromatography, X-ray photoelectron spectroscopy, and microscopy. Pellets were exposed to water containing BTEX and the ethers at 130-190 mg/L for up to two weeks. Aqueous sorbate concentrations were determined by headspace gas chromatography. Sorption to the polymers was correlated with the sorbate's Kow and was significant for BTEX and marginal for the ethers. Due to substantially lower glass transition temperatures, PP showed higher sorption than PS. Aging had no effect on the sorption behavior of PP. PS sorbed less BTEX after aging due to an oxidized surface layer. KW - BTEX KW - Polypropylene KW - Polystyrene KW - Sorption KW - Degradation PY - 2018 U6 - https://doi.org/10.1016/j.envpol.2018.04.127 SN - 0269-7491 VL - 240 SP - 639 EP - 646 PB - Elsevier CY - Amsterdam AN - OPUS4-44990 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nützmann, Kathrin A1 - Kranzmann, Axel A1 - Stephan-Scherb, Christiane T1 - The influence of chromium on early high temperature corrosion of ferritic alloys under SO₂ atmosphere N2 - Comprehensive insights into the early stages of corrosion mechanisms provide fundamental knowledge to further understand and model long time material behaviour. The present work studies the early stages of combined oxidation and sulphidation of ferritic model alloys for time scales up to 250 h at 650 °C to observe the influence of chromium during the corrosion under SO2. Model alloys were used to focus on the reaction of the intended elements: Fe, Cr, S, and O. Pure iron simultaneously forms magnetite and iron sulphide in an early stage of corrosion, covered by a pure oxide layer after 100 h. Iron with 13 wt% Cr shows hematite and mixed Fe-Cr-oxides first, before sulphides nucleate in the inner corrosion zone. With increasing ageing time a magnetite layer is observed below the hematite layer. Quantitative phase fractions of all corrosion products observed were determined from cross section images. Characterization of the Fe13Cr corrosion scale by FIB revealed a highly porous structure in the inner corrosion zone where Cr-rich (Fe, Cr)-sulphides are present, and caused the scale to spall easily. KW - Early stages KW - Sulphidation KW - High temperature corrosion PY - 2018 U6 - https://doi.org/10.1080/09603409.2018.1446705 SN - 0960-3409 VL - 36 IS - 6 SP - 558 EP - 568 PB - Taylor & Francis AN - OPUS4-44707 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 U6 - 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 - Sonntag, Nadja A1 - Skrotzki, Birgit A1 - Stegemann, Robert A1 - Löwe, Peter A1 - Kreutzbruck, M. T1 - The role of surface topography on deformation-induced magnetization under inhomogeneous elastic-plastic deformation N2 - It is widely accepted that the magnetic state of a ferromagnetic material may be irreversibly altered by mechanical loading due to magnetoelastic effects. A novel standardized nondestructive testing (NDT) technique uses weak magnetic stray fields, which are assumed to arise from inhomogeneous deformation, for structural health monitoring (i.e., for detection and assessment of damage). However, the mechanical and microstructural complexity of damage has hitherto only been insufficiently considered. The aim of this study is to discuss the phenomenon of inhomogeneous “self-magnetization” of a polycrystalline ferromagnetic material under inhomogeneous deformation experimentally and with stronger material-mechanical focus. To this end, notched specimens were elastically and plastically deformed. Surface magnetic states were measured by a three-axis giant magnetoresistant (GMR) sensor and were compared with strain field (digital image correlation) and optical topography measurements. It is demonstrated that the stray fields do not solely form due to magnetoelastic effects. Instead, inhomogeneous plastic deformation causes topography, which is one of the main origins for the magnetic stray field formation. Additionally, if not considered, topography may falsify the magnetic signals due to variable lift-off values. The correlation of magnetic vector components with mechanical tensors, particularly for multiaxial stress/strain states and inhomogeneous elastic-plastic deformations remains an issue. KW - Magnetic stray fields KW - Magnetomechanical effect KW - Damage KW - Topography KW - Multiaxial deformation KW - Notch KW - Plastic deformation KW - Metal magnetic memory KW - Digital image correlation KW - Structural steel PY - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-457878 SN - 1996-1944 VL - 11 IS - 9 SP - 1518, 1 EP - 26 PB - MDPI CY - Basel, Switzerland AN - OPUS4-45787 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 U6 - 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 - Häusler, Ines A1 - Darvishi Kamachali, Reza A1 - Hetaba, W. A1 - Skrotzki, Birgit T1 - Thickening of T-1 Precipitates during Aging of a High Purity Al–4Cu–1Li–0.25Mn Alloy N2 - The age hardening response of a high-purity Al–4Cu–1Li–0.25Mn alloy (wt. %) during isothermal aging without and with an applied external load was investigated. Plate shaped nanometer size T1 (Al2CuLi) and θ′ (Al2Cu) hardening phases were formed. The precipitates were analyzed with respect to the development of their structure, size, number density, volume fraction and associated transformation strains by conducting transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM) studies in combination with geometrical Phase analysis (GPA). Special attention was paid to the thickening of T1 phase. Two elementary types of single-layer T1 precipitate, one with a Li-rich (Type 1) and another with an Al-rich (Defect Type 1) central layer, were identified. The results show that the Defect Type 1 structure can act as a precursor for the Type 1 structure. The thickening of T1 precipitates occurs by alternative stacking of These two elementary structures. The thickening mechanism was analyzed based on the magnitude of strain associated with the precipitation transformation normal to its habit plane. Long-term aging and aging under load resulted in thicker and structurally defected T1 precipitates. Several types of defected precipitates were characterized and discussed. For θ′ precipitates, a ledge mechanism of thickening was observed. Compared to the normal aging, an external load applied to the peak aged state leads to small variations in the average sizes and volume fractions of the precipitates. KW - Al-Cu-Li-alloy KW - Precipitation KW - T1 precipitate KW - Microstructure evolution KW - Thickening KW - Creep KW - Volume fraction KW - Number density KW - Strain difference PY - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-471207 SN - 1996-1944 VL - 12 IS - 1 SP - 30, 1 EP - 23 PB - MDPI AN - OPUS4-47120 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nofz, Marianne A1 - Dörfel, Ilona A1 - Sojref, Regine A1 - Wollschläger, Nicole A1 - Mosquera Feijoo, Maria A1 - Schulz, Wencke A1 - Kranzmann, Axel T1 - Thin Sol-Gel Alumina Coating as Protection of a 9% Cr Steel Against Flue Gas Corrosion at 650 °C N2 - Samples of sol-gel alumina coated and uncoated P92 steel were exposed to flue gas at 650 °C for 300 h. As result of this treatment a 50 µm thick bi-layered oxide scale had formed on the surface of the uncoated sample. Below the scale a 40 µm thick inner oxidation zone was detected. In contrast, the porous, micron thick alumina coating enabled the formation of a chromium oxide scale with a thickness of some nanometers at the interface between steel substrate and coating. In this case high temperature corrosion of the steel was prevented so far. KW - Steel KW - Oxide coatings KW - High-temperature corrosion KW - TEM KW - SEM PY - 2018 U6 - https://doi.org/10.1007/s11085-017-9799-0 SN - 0030-770X SN - 1573-4889 VL - 89 IS - 3-4 SP - 453 EP - 470 PB - Springer AN - OPUS4-44472 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Agudo Jácome, Leonardo A1 - Pöthkow, K. A1 - Paetsch, O. A1 - Hege, H.-C. T1 - Three-dimensional reconstruction and quantification of dislocation substructures from transmission electron microscopy stereo pairs N2 - A great amount of material properties is strongly influenced by dislocations, the carriers of plastic deformation. It is therefore paramount to have appropriate tools to quantify dislocation substructures with regard to their features, e.g., dislocation density, Burgers vectors or line direction. While the transmission electron microscope (TEM) has been the most widely-used equipment implemented to investigate dislocations, it usually is limited to the two-dimensional (2D) observation of three-dimensional (3D) structures. We reconstruct, visualize and quantify 3D dislocation substructure models from only two TEM images (stereo pairs) and assess the results. The reconstruction is based on the manual interactive tracing of filiform objects on both images of the stereo pair. The reconstruction and quantification method are demonstrated on dark field (DF) scanning (S)TEM micrographs of dislocation substructures imaged under diffraction contrast conditions. For this purpose, thick regions (> 300 nm) of TEM foils are analyzed, which are extracted from a Ni-base superalloy single crystal after high temperature creep deformation. It is shown how the method allows 3D quantification from stereo pairs in a wide range of tilt conditions, achieving line length and orientation uncertainties of 3% and 7°, respectively. Parameters that affect the quality of such reconstructions are discussed. KW - Dislocation KW - Diffraction contrast KW - Scanning transmission electron microscopy (STEM) KW - Stereoscopy KW - Visualization PY - 2018 U6 - https://doi.org/10.1016/j.ultramic.2018.08.015 SN - 0304-3991 VL - 195 SP - 157 EP - 170 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-46355 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Karl, D. A1 - Kamutzki, F. A1 - Zocca, Andrea A1 - Görke, O. A1 - Günster, Jens A1 - Gurlo, A. T1 - Towards the colonization of Mars by in-situ resource utilization: Slip cast ceramics from Martian soil simulant N2 - Here we demonstrate that by applying exclusively Martian resources a processing route involving suspensions of mineral particles called slurries or slips can be established for manufacturing ceramics on Mars. We developed water-based slurries without the use of additives that had a 51 wt. % solid load resembling commercial porcelain slurries in respect to the particle size distribution and rheological properties. These slurries were used to slip cast discs, rings and vases that were sintered at temperatures between 1000 and 1130 °C using different sintering schedules, the latter were set-up according the results of hot-stage microscopic characterization. The microstructure, porosity and the mechanical properties were characterized by SEM, X-ray Computer tomography and Weibull analysis. Our wet processing of minerals yields ceramics with complex shapes that show similar mechanical properties to porcelain and could serve as a technology for future Mars colonization. The best quality parts with completely vitrificated matrix supporting a few idiomorphic crystals are obtained at 1130 °C with 10 h dwell time with volume and linear shrinkage as much as ~62% and ~17% and a characteristic compressive strength of 51 MPa. KW - Ceramic KW - Mars PY - 2018 U6 - https://doi.org/10.1371/journal.pone.0204025 SN - 1932-6203 VL - 13 IS - 10 SP - e0204025, 1 EP - 7 PB - Public Library of Science CY - San Francisco, Kalifornien, Vereinigte Staaten AN - OPUS4-46612 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kirner, Sabrina V. A1 - Slachciak, Nadine A1 - Elert, Anna Maria A1 - Griepentrog, Michael A1 - Fischer, Daniel A1 - Hertwig, Andreas A1 - Sahre, Mario A1 - Dörfel, Ilona A1 - Sturm, Heinz A1 - Pentzien, Simone A1 - Koter, Robert A1 - Spaltmann, Dirk A1 - Krüger, Jörg A1 - Bonse, Jörn T1 - Tribological performance of titanium samples oxidized by fs-laser radiation, thermal heating, or electrochemical anodization N2 - Commercial grade-1 titanium samples (Ti, 99.6%) were treated using three alternative methods, (i) femtosecond laser processing, (ii) thermal heat treatment, and (iii) electrochemical anodization, respectively, resulting in the formation of differently conditioned superficial titanium oxide layers. The laser processing (i) was carried out by a Ti:sapphire laser (pulse duration 30 fs, central wavelength 790 nm, pulse repetition rate 1 kHz) in a regime of generating laser-induced periodic surface structures (LIPSS). The experimental conditions (laser fluence, spatial spot overlap) were optimized in a sample-scanning setup for the processing of several square-millimeters large surface areas covered homogeneously by these nanostructures. The differently oxidized titanium surfaces were characterized by optical microscopy, micro Raman spectroscopy, variable angle spectroscopic ellipsometry, and instrumented indentation testing. The tribological performance was characterized in the regime of mixed friction by reciprocating sliding tests against a sphere of hardened steel in fully formulated engine oil as lubricant. The specific tribological performance of the differently treated surfaces is discussed with respect to possible physical and chemical mechanisms. KW - Femtosecond laser KW - Titanium KW - Oxidation KW - Friction PY - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-445609 SN - 0947-8396 SN - 1432-0630 VL - 124 IS - 4 SP - 326, 1 EP - 10 PB - Springer-Verlag AN - OPUS4-44560 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 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-464711 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 - Sonntag, Nadja A1 - Cabeza, S. A1 - Kuntner, M. A1 - Mishurova, Tatiana A1 - Klaus, M. A1 - Kling e Silva, L. A1 - Skrotzki, Birgit A1 - Genzel, Ch. A1 - Bruno, Giovanni T1 - Visualisation of deformation gradients in structural steel by macroscopic magnetic domain distribution imaging (Bitter technique) N2 - Abstract While classically used to visualise the magnetic microstructure of functional materials (e.g., for magnetic applications), in this study, the Bitter technique was applied for the first time to visualise macroscopic deformation gradients in a polycrystalline low-carbon steel. Spherical indentation was chosen to produce a multiaxial elastic–plastic deformation state. After removing the residual imprint, the Bitter technique was applied, and macroscopic contrast differences were captured in optical microscopy. To verify this novel characterisation technique, characteristic “hemispherical” deformation zones evolving during indentation were identified using an analytical model from the field of contact mechanics. In addition, near-surface residual stresses were determined experimentally using synchrotron radiation diffraction. It is established that the magnetic domain distribution contrast provides deformation-related information: regions of different domain wall densities correspond to different “hemispherical” deformation zones (i.e., to hydrostatic core, plastic zone and elastic zone, respectively). Moreover, the transitions between these three zones correlate with characteristic features of the residual stress profiles (sign changes in the radial and local extrema in the hoop stress). These results indicate the potential of magnetic domain distribution imaging: visualising macroscopic deformation gradients in fine-grained ferromagnetic material with a significantly improved spatial resolution as compared to integral, mean value-based measurement methods. KW - Bitter technique KW - Deformation KW - Expanding cavity model KW - Indentation KW - Magnetic domain distribution KW - Residual stress PY - 2018 U6 - https://doi.org/10.1111/str.12296 SN - 1475-1305 VL - 54 IS - 6 SP - e12296, 1 EP - 15 PB - Wiley AN - OPUS4-46569 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -