TY - JOUR A1 - Maximilian, Thuy A1 - Spyrantis, Alexander A1 - Böhning, Martin A1 - Niebergall, Ute A1 - Maaß, Robert T1 - Spatially resolved roughness exponent in polymer fracture N2 - The fracture surface of slow and continuous crack propagation during environmental stress cracking of a semicrystalline polyethylene exhibits isotropic roughness exponents at the local scale but resolved across the macroscopic fracture surface a clear position dependence is found. The spatially resolved roughness exponent admits values in the range between 0.1 and 0.4, demonstrating nontrivial exponents in the small length-scale regime. Instead, they vary across the fracture surface according to the stress-state distribution, which suggests that the exponents are intimately linked to the locally dominating dissipation processes during craze cracking. KW - Plasticity KW - Fracture KW - Material failure KW - Mechanical deformation PY - 2022 DO - https://doi.org/10.1103/PhysRevMaterials.6.L090601 VL - 6 IS - 9 SP - 1 EP - 7 PB - American Physical Society CY - USA, Maryland AN - OPUS4-55797 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Blaeß, Carsten A1 - Wilbig, Janka A1 - Müller, Ralf A1 - Nawaz, Q. A1 - Boccaccini, A.R. T1 - 3D printing of crystallizing bioactive glasses N2 - Artificial bone replacement by individual customized three-dimensional resorbable bioactive glass has not yet been widely established in the clinical use. This is mainly due to the antagonism of sintering ability and suitable bioactivity. Competitive crystallization often prevents the generation of dense sintered bodies, especially for additive manufactured 3D structures. Previous studies of the fluoride-containing glass F3 have shown its potential to combine both sintering ability and suitable bioactivity. Furthermore, the occurring sintering blockade by surface crystallization of Na2CaSi2O6 was tunable by glass particle size. In this study the glasses F3, F3-Cu with 1 mol% CuO added at the expense of CaO and the well-known 13-93 were chosen to determine the influence of surface crystallization on 3D printed sinter bodies. For this purpose, grain size fractions in range of smaller 32 µm to 315 µm in fraction size of 6-20 µm were sieved from jaw crushed glass frit as well as glass cubes were cut from casted blocks for all glasses. Sintering behavior of both pressed and printed powder compacts was observed via heating microscopy. Crystallization was determined by DTA and crystallization progress was monitored on fractured sinter bodies and polished cubes via electron and laser scanning microscopy as well as with diffractometry. Depending on grain size the formation of crystalline support framework along former grain boundaries shows the capability to stabilize fully densified sinter bodies before softening. Beside of this, the generation of complex hierarchic porosity was possible as well. T2 - ICG Berlin 2022 CY - Berlin, Germany DA - 03.07.2022 KW - Bioactive Glass KW - Crystallization KW - Sintering KW - 3D printing PY - 2022 AN - OPUS4-55253 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schröder, Jakob A1 - Mishurova, Tatiana A1 - Fritsch, Tobias A1 - Serrano Munoz, Itziar A1 - Evans, Alexander A1 - Sprengel, Maximilian A1 - Klaus, M. A1 - Genzel, C. A1 - Schneider, J. A1 - Bruno, Giovanni T1 - The heat treatment of L-PBF Inconel 718: A manyfold problem N2 - The interest to additively manufacture Nickel-based superalloys has substantially grown within the past decade both academically and industrially. More specifically, additive manufacturing processes such as laser powder bed fusion (LPBF) offer the ability to produce dense parts within a single manufacturing step. In fact, the exceptional freedom in design associated with the layer-based nature of the processes is of particular interest for the complex shapes typically required in turbine applications. In certain cases, the overall part performance can be achieved by tailoring the microstructure and the crystallographic texture to the specific application. However, these advantages must be paid at a price: the large local temperature gradients associated with the rapid melting and solidification produce parts that inherently contain large residual stress in the as-manufactured state. In addition, the presence of pores in the final part may further affect the in-service part failure. As among Nickel-based alloys Inconel 718 exhibits excellent weldability, this alloy has been widely studied in open research in the domain of LPBF. However, significant microsegregation of the heavier alloying elements such as Niobium and Molybdenum accompanied by dislocation entanglements may preclude the application of conventional heat treatment schedules. Therefore, different post processing heat treatments are required for laser powder bed fused Inconel 718 as compared to conventional variants of the same alloy. In this study, we investigated two different heat treatment routes for LPBF Inconel 718. In a first routine, the samples were stress relieved and subsequently subjected to hot isostatic pressing (HIP) followed by a solution heat treatment and a two-step age (referred to as FHT). In a second routine, the samples were subjected to a single-step direct age post stress relieving heat treatment (referred to DA). We investigated the consequences of such heat treatment schedules on the microstructure, texture, and mechanical behavior. We show that by applying a DA heat treatment the typical columnar microstructure possessing a crystallographic texture is retained, while an equiaxed untextured microstructure prevails in case of an FHT heat treatment. We further evaluate how these heat treatments affect the mechanical behaviour on the macroscopic and microscopic scale. T2 - 4th European Symposium on Superalloys and their Applications EuroSuperalloys 2022 CY - Bamberg, Germany DA - 18.09.2022 KW - Electron Backscatter Diffraction KW - Additive Manufacturing KW - Laser Powder Bed Fusion KW - Mechanical Behavior KW - Heat Treatment KW - X-Ray Diffraction PY - 2022 AN - OPUS4-55811 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schönauer-Kamin, Daniela A1 - Hetzel, K. A1 - Moos, R. A1 - Bresch, Sophie T1 - Powder-Aerosol deposited (PAD) calcium manganate as n-type thermoelectric material N2 - Currently, calcium manganate CaMnO3 and calcium cobaltite Ca3Co4O9 are being investigated as n-type resp. p-type semiconducting materials as oxidation- and temperature-resistant thermoelectric materials for oxide multilayer thermoelectric generators (TEGs). In order to manufacture multilayer TEGs, pressure-assisted sintering processes at high temperatures are necessary to achieve optimal thermoelectric material properties. To realize TEGs in planar film technology, another method to obtain dense ceramic layers directly from the synthesized starting powders without a subsequent high temperature step is emerging recently: the powder aerosol deposition (PAD) method. In the present work, it is investigated whether PAD is suitable to produce dense ceramic films from Sm-doped CaMnO3 and Ca3Co4O9 powders. The resulting thermoelectric properties are characterized as a function of temperature. CaMnO3 powder could successfully be processed by PAD with resulting layer thicknesses of 5- 6 µm without any high-temperature sintering steps of the films. The electrical conductivity and the Seebeck coefficient of the films were determined in-plane from room temperature to 600 °C in air. The results show a Seebeck coefficient of around -200 µV/K, which is comparable to results of pressed and sintered bars. At 400 °C, the electrical conductivity corresponds to the conductivity of the bar. At higher temperatures the conductivity is better than with the reference. Below 400°C, the electrical conductivity is somewhat lower than that of the reference sample, a mild thermal treatment of the PAD layer improves it. It is expected that the thermal conductivity of the PAD film will be lower compared to the bars due to the nano-crystalline film morphology. This should result in a significantly increased ZT value for the PAD layers and a higher efficiency of the TEG. The work shows that both CaMnO3 and Ca3Co4O9 can be successfully processed by PAD, and the PAD films show comparable thermoelectric properties. T2 - 18th European Conference on Thermoelectrics CY - Barcelona, Spanien DA - 14.09.2022 KW - Film depositition KW - Calcium cobaltite PY - 2022 AN - OPUS4-55771 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Heuser, Lina A1 - Müller, Ralf A1 - Nofz, Marianne A1 - Deubener, J. T1 - Liquid phase sintering of alkali zinc borate glass-bearing silver pastes for applications in photovoltaics and microelectronics N2 - Liquid phase sintering of glass bearing silver pastes used in photovoltaics and microelectronics is poorly understood. In particular, the role of different network modifiers acting in the glass component and the question of the most suitable atmospheric oxygen level during sintering are still under considerable debate. To tackle these issues, low-melting and lead-free X2O-ZnO-B2O3 glasses with X = Li, Na, K and Rb (LZB, NZB, KZB and RZB) were prepared. Infrared spectroscopy showed that the glass structure was similar to each other, while an increase of tetrahedrally coordinated boron with increasing field strength of the alkali was evident. In turn, the glass transition temperature (from differential thermal analysis) increased in the order: RZB (449 °C) < KZB (460 °C) < NZB (465 °C) < LZB (472 °C). Powders of each glass were mixed with organics to receive silver-glass-pastes containing 30 vol% glass and these were subjected to heating microscopy in air. Although similar onset temperatures of sintering were recorded for Ag-NZB and Ag-LZB glass pastes, and for Ag-RZB paste and KZB-Ag-paste, respectively, differences in the crystallization behavior and final densification were observed between the former and the latter group. These were translated in terms of differences in silver dissolution and reprecipitation among the two groups. Further, running the experiments in nitrogen gas showed that sintering of all pastes was considerably hampered. The slow-down of the sinter kinetics was found to be in line with the assumed lower oxidation and dissolution of silver ions into the glass-forming liquid. T2 - 26th International Congress on Glass CY - Berlin, Germany DA - 03.07.2022 KW - Silver metallization paste KW - Sintering KW - Glass KW - Alkali zinc borate glasses KW - Viscosity KW - Structure PY - 2022 AN - OPUS4-55728 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Heuser, Lina A1 - Roßmöller-Felz, Mattis A1 - Nofz, Marianne A1 - Müller, Ralf A1 - Deubener, J. T1 - In situ observation of silver precipitation in sodium zinc borate glass-forming melts N2 - Melting of Na2CO3-ZnO-B2O3 batches containing up to 16.8 wt% AgNO3 (5 mol% Ag2O in the target glass composition) was observed in situ by means of hot stage microscopy. In all batches metallic silver precipitation took place as most of the silver nitrate was reduced to metallic silver before Ag+ ions could be dissolved in the evolving borate melts. In turn, only traces of Ag+ (<300 ppmw) were dissolved in the sodium zinc borate glass melts under study. It is assumed that the oxidation to Ag+ was limited due to poor availability of reducible oxygen in the glass melts and presence of Na2O being a stronger base than Ag2O. Thus, the precipitated metallic silver formed droplets of different sizes. The larger droplets (d > 20 µm) were already settled at the bottom of the container and remained constant in size upon dwelling for 1 h at 1050 °C of about one hour and the subsequent cooling (45 K/min) to room temperature, whereas the smaller droplets (d < 20 µm) were mobile in the borate melt due to Marangoni and Stokes motion. For the latter droplets, coalescence was observed in situ. A growth of larger droplets at the expense of smaller ones, i.e., Ostwald ripening was also expected but could not be studied with the used experimental equipment. T2 - 26th International Congress on Glass CY - Berlin, Germany DA - 03.07.2022 KW - Glass melt KW - Silver KW - Sodium zinc borate glass KW - Hot stage microscopy KW - Precipitation PY - 2022 AN - OPUS4-55732 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Tiebe, Carlo A1 - Maiwald, Michael A1 - Bresch, Sophie A1 - Prager, Jens A1 - Lugovtsova, Yevgeniya A1 - Schukar, Marcus A1 - Munzke, Dorit A1 - Duffner, Eric A1 - Eisermann, René A1 - Schoppa, André A1 - Szczepaniak, Mariusz A1 - Strohhäcker, J. A1 - Mair, Georg T1 - Sensoren und Analytik für Sicherheit und Prozesskontrolle in Wasserstofftechnologien N2 - Der Beitrag beinhaltet Themen vom H2Safety@BAM-Kompetenzfeld Sensorik, Analytik und zertifizierte Referenzmaterialien (SensRef) mit Fokus auf Mess- und Prüfverfahren mit verschiedenen Sensortechnologien und Ultraschallwellen: Metrologie zur Wasserstoffspeicherung - Euramet-Vorhaben "MefHySto", Erkennung von freigesetztem Wasserstoff sowie die Bestimmung des Wasserstoff-Luftverhälntisses mit Gassensoren, zerstörungsfreie Fehlstellenerkennung mit integriertem Zustandsüberwachungssystem basierend auf geführten Ultraschallwellen zur Lebensdauerüberwachung von Composite-Behältern (Wasserstoffspeicher) sowie faseroptische Sensorik zur Schadenfrüherkennung von Wasserstoffspeichern aufgrund erkennbarer Dehnungsänderungen an Druckbehältern. T2 - DVGW Kongress H2 Sicherheit CY - Online meeting DA - 23.11.2022 KW - H2Safety@BAM KW - SensRef KW - Faseroptische Sensorik KW - Gassensorik KW - Geführte Ultraschallwellen KW - Leckdetektion KW - Metrologie zur Wasserstoffspeicherung KW - Zerstörungsfreie Prüfung KW - Structural Health Monitoring (SHM) PY - 2022 AN - OPUS4-56683 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Malakhov, A. A1 - Epishin, A. A1 - Denisov, I. A1 - Saikov, I. A1 - Nolze, Gert T1 - Morphology and Structure of Brass–Invar Weld Interface after Explosive Welding N2 - This paper presents the results of a study of the morphology and structure at the weld interface in a brass–Invar bimetal, which belongs to the class of so-called thermostatic bimetals, or thermobimetals. The structure of the brass–Invar weld interface was analyzed using optical microscopy and scanning electron microscopy (SEM), with the use of energy-dispersive X-ray (EDX) spectrometry and back-scattered electron diffraction (BSE) to identify the phases. The distribution of the crystallographic orientation of the grains at the weld interface was obtained using an e-Flash HR electron back-scatter diffraction (EBSD) detector and a forward-scatter detector (FSD). The results of the study indicated that the weld interface had the wavy structure typical of explosive welding. The wave crests and troughs showed the presence of melted zones consisting of a disordered Cu–Zn–Fe–Ni solid solution and undissolved Invar particles. The pattern quality map showed that the structure of brass and Invar after explosive welding consisted of grains that were strongly elongated towards the area of the highest intensive plastic flow. In addition, numerous deformation twins, dislocation accumulations and shear bands were observed. Thus, based on the results of this study, the mechanism of Cu–Zn–Fe–Ni structure formation can be proposed. KW - Explosive welding KW - Thermobimetal KW - Grain structure KW - Brass KW - Invar PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-565964 DO - https://doi.org/10.3390/ma15238587 SN - 1996-1944 VL - 15 IS - 23 SP - 1 EP - 10 PB - MDPI AN - OPUS4-56596 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Shakeel, Y. A1 - Soysal, M. A1 - Vitali, E. A1 - Ost, P. A1 - Aversa, R. A1 - Ávila Calderón, Luis Alexander A1 - Engstler, M. A1 - Fell, J. A1 - Fritzen, F. A1 - Hermmann, H.-G. A1 - Laadhar, A. A1 - Olbricht, Jürgen A1 - Pauly, C. A1 - Roland, M. A1 - Skrotzki, Birgit T1 - NFDI-MatWerk - Reference Datasets N2 - Within NFDI-MatWerk (“National Research Data Infrastructure for Material Sciences”/ “Nationale Forschungsdateninfrastruktur für Materialwissenschaften und Werkstofftechnik“), the Task Area Materials Data Infrastructure (TA-MDI) will provide tools and services to easily store, share, search, and analyze data and metadata. Such a digital materials environment will ensure data integrity, provenance, and authorship. The MatWerk consortium aims to develop specific solutions jointly with Participant Projects (PPs), which are scientific groups or institutes covering different domains, from theory and simulations to experiments. The Data Exploitation Methods group of the Karlsruhe Institute of Technology-Steinbuch Centre of Computing, as part of TA-MDI, is developing specific solutions in close collaboration with three PPs. PP07, together with the University of Stuttgart, aims at the image-based prediction of the material properties of stochastic microstructures using large-scale supercomputers. PP13, in cooperation with the University of Saarland, focuses on tomographic methods at various scales in materials research. PP18, together with the Federal Institute for Materials Research and Testing (“Bundesanstalt für Materialforschung und -prüfung”), aspires to define the criteria for materials reference datasets and usage analytics. The requirements and goals are comparable for each PP: their research outputs, which are scientific datasets, should conform to the FAIR (Findable, Accessible, Interoperable, Reusable) principles. We aim to shape them from a data management perspective making use of the FAIR Digital Object concept, including structured metadata and storage solutions. The results will be a blueprint which will act as a reference for future datasets. Even though the collaboration is in an early stage, the initial steps already show the added value of this approach. This research has been supported by the Federal Ministry of Education and Research (BMBF) – funding code M532701 / the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) - project number NFDI 38/1, project no. 460247524. T2 - HMC Conference 2022 CY - Online meeting DA - 05.10.2022 KW - NFDI KW - NFDI-MatWerk KW - Reference Data KW - FAIR KW - Creep PY - 2022 AN - OPUS4-56611 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Winckelmann, Alexander A1 - Hoffmann, Volker A1 - Morcillo, Dalia A1 - Agudo Jácome, Leonardo A1 - Leonhardt, Robert A1 - Richter, Silke A1 - Recknagel, Sebastian A1 - Abad Andrade, Carlos Enrique A1 - You, Zengchao T1 - Investigation of degradation of the aluminum current collector in lithium-ion batteries by GD-OES N2 - Lithium-ion batteries (LIBs) are one technology to overcome the challenges of climate and energy crisis. They are widely used in electric vehicles, consumer electronics, or as storage for renewable energy sources. However, despite innovations in batteries' components like cathode and anode materials, separators, and electrolytes, the aging mechanism related to metallic aluminum current collector degradation causes a significant drop in their performance and prevents the durable use of LIBs. Glow-discharge optical emission spectroscopy (GD-OES) is a powerful method for depth-profiling of batteries' electrode materials. This work investigates aging-induced aluminum deposition on commercial lithium cobalt oxide (LCO) batteries' cathodes. The results illustrate the depth-resolved elemental distribution from the cathode surface to the current collector. An accumulation of aluminum is found on the cathode surface by GD-OES, consistent with results from energy-dispersive X-ray spectroscopy (EDX) combined with focused ion beam (FIB) cutting. In comparison to FIB-EDX, GD-OES allows a fast and manageable depth-profiling. Results from different positions on an aged cathode indicate an inhomogeneous aluminum film growth on the surface. The conclusions from these experiments can lead to a better understanding of the degradation of the aluminum current collector, thus leading to higher lifetimes of LIBs. T2 - Empa Group Meeting CY - Dübendorf, Switzerland DA - 22.11.2022 KW - Lithium Ion Batteries KW - GD-OES KW - FIB KW - SEM KW - EDX PY - 2022 AN - OPUS4-56584 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rodrigues, A. C. P. A1 - Feller, A. A1 - Agudo Jácome, Leonardo A1 - Azevedo, C. R. F. T1 - Use of synthetic Fe3O4-rich tribofilms to investigate the effect of microconstituents, temperature and atmosphere on the friction coefficient during pin-on-disc tribotest N2 - This work investigates the effect of the tribotesting parameters (temperature, atmosphere, and third body chemical composition) on the coefficient of friction (CoF) during pin-on-disc dry (PoD) sliding tribotests using artificial third bodies. The third body comprised nanometric Fe3O4-based binary to quaternary chemical compositions containing copper, graphite, and zirconia. These mixtures were manually or ball-milled prepared, and pin-on-disc tribotests were conducted at 23 °C and 400 °C under air or nitrogen atmospheres. Combining PoD and artificial third body to create synthetic tribofilms might be useful for testing new formulations of Cu-free friction materials. Microstructural characterisation of the tribofilms was used to study the stability of the Fe3O4, copper, and graphite nanoparticles under different testing conditions to understand their effects on the CoF. For the Fe3O4-C-ZrO2-X systems, the ball milling mixing promoted the formation of turbostratic graphite in the tribofilm, impairing the lubricating effect of the graphite under air atmosphere at 23 °C. The formation of monoclinic CuO in the tribofilms during tribotests at 400 °C under air and N2 atmospheres promoted a lubricating effect. KW - Tribology KW - Microstructure KW - Oxide KW - Transmission electron microscopy PY - 2022 DO - https://doi.org/10.1088/2051-672X/ac9d51 SN - 2051-672X VL - 10 IS - 4 SP - 044009-1 EP - 044009-18 PB - IOP Pobilishing AN - OPUS4-56467 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sänger, Johanna Christiane A1 - Pauw, Brian Richard A1 - Riechers, Birte A1 - Zocca, Andrea A1 - Rosalie, Julian A1 - Maaß, Robert A1 - Sturm, Heinz A1 - Günster, Jens T1 - Entering a new dimension in powder processing for advanced ceramics shaping N2 - Filigree structures can be manufactured via two-photon-polymerization (2PP) operating in the regime of non-linear light absorption. For the first time it is possible to apply this technique to the powder processing of ceramic structures with a feature size in the range of the critical defect size responsible for brittle fracture and, thus, affecting fracture toughness of high-performance ceramics. In this way, tailoring of advanced properties can be achieved already in the shaping process. Traditionally, 2PP relies on transparent polymerizable resins, which is diametrically opposed to the usually completely opaque ceramic resins and slurries. Here we present a transparent and photocurable suspension of nanoparticles (resin) with very high mass fractions of yttria-stabilized zirconia particles (YSZ). Due to the extremely well dispersed nanoparticles, scattering of light can be effectively suppressed at the process-relevant wavelength of 800 nm. Sintered ceramic structures with a resolution of down to 500 nm were obtained. Even at reduced densities of 1 to 4 g/cm³, the resulting compressive strength with 4,5 GPa is equivalent or even exceeding bulk monolithic yttria stabilized zirconia. A ceramic metamaterial is born, where the mechanical properties of yttria stabilized zirconia are altered by changing geometrical parameters and gives access to a new class of ceramic materials. KW - Two-photon-polymerization KW - Ceramics KW - Powder processing KW - Transparency KW - Meta material KW - Yttria stabilized zirconia PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-564598 DO - https://doi.org/10.1002/adma.202208653 SN - 1521-4095 SP - 1 EP - 8 PB - Wiley-VCH CY - Weinheim AN - OPUS4-56459 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Epishin, A.I. A1 - Nolze, Gert A1 - Alymov, M.I. T1 - Pore Morphology in Single Crystals of a Nickel-Based Superalloy After Hot Isostatic Pressing N2 - The morphology of pores partially shrunk during a half-hour HIP at temperature of 1288 °C and pressure of 103 MPa has been investigated in nickel-based superalloy CMSX-4. The investigation resulted in the following findings: surrounding the shrinking pores by a c¢-shell (Ni3Al), faceting of the pores surface by {023} and {011} planes, and formation the submicroscopic satellite pores connected by channels with the neighboring larger pores. It is assumed that the formation of the c¢-shell around the pores and the faceting of the pore surface is due to diffusion processes occurring during pore shrinkage, and therefore these findings can be considered as arguments supporting the vacancy model of pore annihilation. The submicroscopic satellite pores are expected to be the result of dividing the casting pores of a complex initial shape during their shrinking. The connecting channels are probably required for the gas to escape from the rapidly shrinking small satellite pores into the slowly shrinking large pore. Thus, it is reasonable to assume that the casting pores may contain some amount of gas. KW - HIP KW - Superalloy KW - Porosity KW - Faceting KW - negative crystal growth PY - 2022 DO - https://doi.org/10.1007/s11661-022-06893-x SN - 1073-5623 SP - 1 EP - 9 PB - Springer Nature AN - OPUS4-56409 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Yesilcicek, Yasemin A1 - Haas, S. A1 - Suárez Ocano, Patricia A1 - Zaiser, E. A1 - Hesse, René A1 - Többens, D. M. A1 - Glatzel, U. A1 - Manzoni, Anna Maria T1 - Controlling Lattice Misfit and Creep Rate Through the γ' Cube Shapes in the Al10Co25Cr8Fe15Ni36Ti6 Compositionally Complex Alloy with Hf and W Additions N2 - Trace elements play an important role in the fine-tuning of complex material properties. This study focuses on the correlation of microstructure, lattice misfit and creep properties. The compositionally complex alloy Al10Co25Cr8Fe15Ni36Ti6 (in at. %) was tuned with high melting trace elements Hf and W. The microstructure consists of a γ matrix, γ' precipitates and the Heusler phase and it is accompanied by good mechanical properties for high temperature applications. The addition of 0.5 at.% Hf to the Al10Co25Cr8Fe15Ni36Ti6 alloy resulted in more sharp-edged cubic γ′ precipitates and an increase in the Heusler phase amount. The addition of 1 at.% W led to more rounded γ′ precipitates and the dissolution of the Heusler phase. The shapes of the γ' precipitates of the alloys Al9.25Co25Cr8Fe15Ni36Ti6Hf0.25W0.5 and Al9.25Co25Cr8Fe15Ni36Ti6Hf0.5W0.25, that are the alloys of interest in this paper, create a transition from the well-rounded precipitates in the alloy with 1% W containing alloy to the sharp angular particles in the alloy with 0.5% Hf. While the lattice misfit has a direct correlation to the γ' precipitates shape, the creep rate is also related to the amount of the Heusler phase. The lattice misfit increases with decreasing corner radius of the γ' precipitates. So does the creep rate, but it also increases with the amount of Heusler phase. The microstructures were investigated by SEM and TEM, the lattice misfit was calculated from the lattice parameters obtained by synchrotron radiation measurements. KW - High entropy alloy KW - Lattice misfit KW - Creep KW - Transmission electron microscopy KW - X-ray diffraction PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-565655 DO - https://doi.org/10.1007/s44210-022-00009-1 SP - 1 EP - 9 PB - Springer AN - OPUS4-56565 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Brandić Lipińska, M. A1 - Davenport, R. A1 - Imhof, A. B. A1 - Waclavicek, R. A1 - Fateri, M. A1 - Meyer, Lena A1 - Gines-Palomares, J. C. A1 - Zocca, Andrea A1 - Makaya, A. A1 - Günster, Jens T1 - PAVER - Contextualizing laser sintering within a lunar technology roadmap N2 - The Global Exploration Strategy of the International Space Exploration Coordination Group (ISECG) describes a timeframe of 2020 and beyond with the ultimate aim to establish a human presence on Mars towards the 2040ies. The next steps lie on the Moon with a focus on the coming 10 years. Early lunar surface missions will establish a capability in support of lunar science and prepare and test mission operations for subsequent human exploration of Mars and long-duration human activities on the Moon. Given the extreme costs involved in the shipping of material from Earth, a prerequisite for future human exploration is the manufacturing of elements directly on the Moon’s surface. Unlike the equipment, which at the beginning will have to be brought from Earth, raw materials and energy could be available following the concept of In-Situ Resource Utilization. The ESA OSIP PAVING THE ROAD (PAVER) study investigates the use of a laser to sinter regolith into paving elements for use as roadways and launch pads thus mitigating dust issues for transport and exploration vehicles. The ESA-funded study examines the potential of using a laser (12 kW CO2 laser with spot beam up to 100 mm) for layer sintering of lunar and martian regolith powders to manufacture larger 3D elements and provide know-how for the automatic manufacture of paving elements in the lunar environment. The project contributes to the first step toward the establishment of a lunar base and will lead to the construction of equipment capable of paving areas and manufacturing 3D structures. PAVER project sets the starting point for an examination of the larger context of lunar exploration. Mission scenarios will look at different phases of lunar exploration: Robotic Lunar Exploration, Survivability, Sustainability, and Operational Phase. A proposed Technology Roadmap investigates the mission scenario and analyses how, and to which extent, laser melting/sintering will play a role in the various phases of exploration. The paper contextualizes laser sintering within selected mission scenarios and discusses the different kinds of infrastructure that can be produced at each phase of the mission. The outcome of the study includes the detailing of the TRL steps in the project and an outline of a timeline for the different elements. Covered aspects include terrain modelling such as operation pads, roadways, or towers, non-pressurized building structures to protect machinery, and habitat envelopes, to protect and shield humans against dust, micrometeoroids, and radiation. T2 - 73rd International Astronautical Congress (IAC) CY - Paris, France DA - 18.09.2022 KW - Additive manufacturing KW - Solar sintering KW - ISRU KW - Infrastructure KW - Lunar habitat KW - Paving PY - 2022 SP - 1 EP - 9 AN - OPUS4-56519 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Günster, Jens A1 - Meyer, Lena T1 - Laser beam melting additive manufacturing at μ-gravity N2 - At the Workshop "Neutron and Synchrotron Monitoring in Aerospace Advanced Manufacturing" at the Institute of Materials Physics in Space, German Aerospace Center (DLR) in Cologne, we presented on the opportunities and our experiences of using a powder based additive manufacturing process for in-space manufacturing applications in microgravity. T2 - Workshop 'Neutron and Synchrotron Monitoring in Aerospace Advanced Manufacturing' CY - Cologne, Germany DA - 11.08.2022 KW - Additive manufacturing KW - In-space manufacturing KW - Microgravity KW - μ-gravity KW - Laser beam melting KW - Advanced manufacturing KW - Aerospace KW - Process monitoring PY - 2022 AN - OPUS4-56521 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Zocca, Andrea A1 - Schubert, Hendrik A1 - Günster, Jens T1 - Combination of layerwise slurry deposition and binder jetting (lsd-print) for the additive manufacturing of advanced ceramic materials N2 - Powder bed technologies are amongst the most successful Additive Manufacturing (AM) techniques. Powder bed fusion and binder jetting especially are leading AM technologies for metals and polymers, thanks to their high productivity and scalability. The application of these techniques to most ceramics has been difficult so far, because of the challenges related to the deposition of homogeneous powder layers when using fine powders. In this context, the “layerwise slurry deposition” (LSD) has been developed as a layer deposition method which enables the use of powder bed AM technologies also for advanced ceramic materials. The layerwise slurry deposition consists of the layer-by-layer deposition of a ceramic slurry by means of a doctor blade, in which the slurry is deposited and dried to achieve a highly packed powder layer. This offers high flexibility in the ceramic feedstock used, especially concerning material and particle size. The LSD technology can be combined with binder jetting to develop the so-called “LSDprint” process for the additive manufacturing of ceramics. The LSDprint technology combines the high-speed printing of binder jetting with the possibility of producing a variety of high-quality ceramics with properties comparable to those achieved by traditional processing. In this presentation, the LSD process will be introduced and several examples of application ranging from silicate to high-performance ceramics will be shown. Recent developments towards the scale-up and industrialization of this process will be discussed, alongside future perspectives for the multi-material additive manufacturing. T2 - Shaping 8 CY - Dübendorf, Switzerland DA - 14.09.2022 KW - Additive Manufacturing KW - 3D printing KW - Ceramics PY - 2022 AN - OPUS4-56523 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schröder, Jakob A1 - Evans, Alexander A1 - Polatidis, E. A1 - Capek, J. A1 - Mohr, Gunther A1 - Serrano Munoz, Itziar A1 - Bruno, Giovanni T1 - Texture Dependent Micromechanical Anisotropy of Laser Powder Bed Fused Inconel 718 N2 - Additive manufacturing methods such as laser powder bed fusion (LPBF) allow geometrically complex parts to be manufactured within a single step. However, as an aftereffect of the localized heat input, the rapid cooling rates are the origin of the large residual stress (RS) retained in as-manufactured parts. With a view on the microstructure, the rapid directional cooling leads to a cellular solidification mode which is accompanied by columnar grown grains possessing crystallographic texture. The solidification conditions can be controlled by the processing parameters and the scanning strategy. Thus, the process allows one to tailor the microstructure and the texture to the specific needs. Yet, such microstructures are not only the origin of the mechanical anisotropy but also pose metrological challenges for the diffraction-based RS determination. In that context the micromechanical elastic anisotropy plays an important role: it translates the measured microscopic strain to macroscopic stress. Therefore, it is of uttermost importance to understand the influence of the hierarchical microstructures and the texture on the elastic anisotropy of LPBF manufactured materials. This study reveals the influence of the build orientation and the texture on the micro-mechanical anisotropy of as-built Inconel 718. Through variations of the build orientation and the scanning strategy, we manufactured specimens possessing [001]/[011]-, [001]-, and [011]/[111]-type textures. The resulting microstructures lead to differences in the macroscopic mechanical properties. Even further, tensile in-situ loading experiments during neutron diffraction measurements along the different texture components revealed differences in the microstrain response of multiple crystal lattice planes. In particular, the load partitioning and the residual strain accumulation among the [011]/[111] textured specimen displayed distinct differences measured up to a macroscopic strain of 10 %. However, the behavior of the specimens possessing [001]/[011]-and [001]-type texture was only minorly affected. The consequences on the metrology of RS analysis by diffraction-based methods are discussed. T2 - International Conference on Additive Manufacturing ICAM 2022 CY - Orlando, FL, USA DA - 31.10.2022 KW - Laser powder bed fusion KW - Neutron diffraction KW - Electron backscatter diffraction KW - Mechanical behavior PY - 2022 AN - OPUS4-56376 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Meyer, Lena A1 - Brandić Lipińska, M. A1 - Davenport, R. A1 - Imhof, A. B. A1 - Waclavicek, R. A1 - Fateri, M. A1 - Gines-Palomares, J. C. A1 - Zocca, Andrea A1 - Makaya, A. A1 - Günster, Jens T1 - How will we explore, work, and live on the moon? N2 - 3D-printed landing pads on the moon: Paving the road for large area sintering of lunar regolith. A prerequisite for lunar exploration and beyond is the manufacturing of objects directly on the moon, given the extreme costs involved in the shipping of material from Earth. Looking at processes, raw materials, and energy sources, equipment will certainly have to be brought from Earth at the beginning. Available on the moon are lunar regolith as raw material and the sun as an energy source. One of the first steps towards the establishment of a lunar base is the creation of infrastructure elements, such as roads and landing pads. We’ll introduce you to the ESA-project PAVER that demonstrates the sintering and melting of lunar regolith simulant material to produce large scale 3D printed elements that could be used during human and robotic lunar explorations. T2 - Berlin Science Week CY - Online meeting DA - 09.11.2022 KW - Additive manufacturing KW - Lunar regolith simulant KW - EAC-1A KW - Space exploration PY - 2022 UR - https://www.youtube.com/watch?v=StfLuVhKkUE AN - OPUS4-56377 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Guerra, E. S. S. A1 - Silva, B. L. A1 - Melo, J. D. D. A1 - Kalinka, Gerhard A1 - Barbosa, A. P. C. T1 - Microscale evaluation of epoxy matrix composites containing thermoplastic healing agent N2 - Among the strategies to produce healable thermosetting systems is their modification by the addition of thermoplastic particles. This work investigates the influence of poly(ethylene-co-methacrylic acid) (EMAA) on fibermatrix interfacial properties of a glass fiber reinforced epoxy matrix composite. Epoxy-EMAA interactions were evaluated using differential scanning calorimetry (DSC) and infrared spectroscopy. The effects of EMAA on the epoxy network formation were evidenced by changes in glass transition temperature, cure kinetics and alteration of chemical groups during cure. Interfacial shear strength (IFSS) measurements obtained by single fiber pull-out tests indicate similar interfacial properties for pure and EMAA modified epoxy. Additionally, the potential for self-healing ability of an EMAA modified epoxy was demonstrated. However, IFSS after a healing cycle for the EMAA modified epoxy was lower as compared to the pure epoxy, because of the lower fiber-EMAA interfacial shear strength. So, thermoplastic healing agents has not only to fill cracks in the matrix material, but also have to be optimized regarding its interface properties to the reinforcing fibers. KW - Interfacial strength KW - Fiber/matrix bond KW - Self-healing KW - Polymer-matrix composites (PMC) PY - 2022 DO - https://doi.org/10.1016/j.compscitech.2022.109843 SN - 0266-3538 VL - 232 SP - 1 EP - 9 PB - Elsevier Ltd. CY - Niederlande AN - OPUS4-56379 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -