TY - CONF
A1 - Ayerdi Gomez, A.
A1 - Slachciak, Nadine
A1 - Zubia Aranburu, J.
A1 - Zabala, A.
A1 - Aginagalde, A.
A1 - Bonse, Jörn
A1 - Spaltmann, Dirk
T1 - Improvement of the tribological performance of titanium alloy using FS-laser-induced periodic surface structures in combination with ZDDP and ionic liquid lubricant additives
N2 - The performance of titanium alloy (Ti6Al4V) surfaces was investigated in lubricated reciprocating sliding tribological tests (RSTT). Special emphasis was laid on the effect of surface nanostructures in area of contact on the respective friction and wear behaviour. These so-called laser-induced periodic surface structures (LIPSS, ripples) were produced on the titanium alloy surface upon scan processing in air by an ultrashort pulsed femtosecond (fs) laser. As lubricant served two types of base oils, a pure polyalcylene-glycol, and an SAE 0W30 oil containing only antioxidants and temperature stabilizers. Tribological tests were carried out on polished as well as LIPSS covered areas using both types of base oil. A test metrics was established, combining the additive 2-ethylhexyl-zincdithiophosphate (ZDDP) or the ionic liquid [P6,6,6,14] [DEHP] (98% purity) with the respective base oils. The test metrics also considered the orientation of motion with respect to the orientation of the structures formed on the surface. Results are presented which show that the interplay between LIPSS and the local chemistry formed by the respective additives is beneficial for the tribological behaviour of the titanium alloy. Certain combinations of base oil, additive and LIPSS reduced friction and wear significantly in the tribological contact.
T2 - 64. Tribologie-Fachtagung
CY - Göttingen, Germany
DA - 25.09.2023
KW - TiAl64V
KW - 100Cr6
KW - Friction
KW - Wear
KW - LIPSS
KW - Lubrication
KW - PAG
KW - Ionic liquid
PY - 2023
SP - 1
EP - 5
AN - OPUS4-58642
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rethmeier, Michael
A1 - Artinov, Antoni
A1 - Meng, Xiangmeng
A1 - Bakir, Nasim
A1 - Üstündag, Ömer
A1 - Bachmann, Marcel
A1 - Gumenyuk, Andrey
T1 - The bulging effect and its relevance in high power laser beam welding
N2 - The present work deals with the recently confirmed widening of the weld pool interface, known as a bulging effect, and its relevance in high power laser beam welding. A combined experimental and numerical approach is utilized to study the influence of the bulge on the hot cracking formation and the transport of alloying elements in the molten pool. A technique using a quartz glass, a direct-diode laser illumination, a high-speed camera, and two thermal imaging cameras is applied to visualize the weld pool geometry in the longitudinal section. The study examines the relevance of the bulging effect on both, partial and complete penetration, as well as for different sheet thicknesses ranging from 8 mm to 25 mm. The numerical analysis shows that the formation of a bulge region is highly dependent on the penetration depth and occurs above 10 mm penetration depth. The location of the bulge correlates strongly with the cracking location. The obtained experimental and numerical results reveal that the bulging effect increases the hot cracking susceptibility and limits the transfer of alloying elements from the top of the weld pool to the weld root.
T2 - 1st Annual Assembly and Conference of The Welding Federation of Africa (TWF-Africa)
CY - Cairo, Egypt
DA - 14.03.2023
KW - Laser beam welding
KW - Melt pool dinamics
PY - 2023
AN - OPUS4-58695
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Meng, Xiangmeng
A1 - Putra, Stephen Nugraha
A1 - Bachmann, Marcel
A1 - Rethmier, Michael
T1 - Influence of the spatial laser energy absorption on the molten pool dynamics in high-power laser beam welding
N2 - The spatial laser energy absorption inside the keyhole is decisive for the dynamic molten pool behaviors and the resultant weld properties in high-power laser beam welding (LBW). In this paper, a numerical simulation of the LBW process, considering the 3D transient heat transfer, fluid flow, and keyhole dynamics, is implemented, in which the free surface is tracked by the volume-of-fluid algorithm. The underlying laser-material interactions, i.e., the multiple reflections and Fresnel absorption, are considered by an advanced ray-tracing method based on a localized level-set strategy and a temperature-dependent absorption coefficient. The laser energy absorption is analyzed from a time-averaged point of view for a better statistical representation. It is found for the first time that a significant drop in the time-averaged laser energy absorption occurs at the focus position of the laser beam and that the rest of the keyhole region has relatively homogeneous absorbed energy. This unique absorption pattern may lead to a certain keyhole instability and have a strong correlation with the detrimental bulging and narrowing phenomena in the molten pool. The influence of different focus positions of the laser beam on the keyhole dynamics and molten pool profile is also analyzed. The obtained numerical results are compared with experimental measurements to ensure the validity of the proposed model.
KW - Laser beam welding
KW - Laser energy absorption
KW - Molten pool
KW - Keyhole dynamics
KW - Numerical modeling
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-587531
DO - https://doi.org/10.2351/7.0001078
SN - 1042-346X
VL - 35
IS - 4
SP - 1
EP - 8
PB - AIP Publishing
AN - OPUS4-58753
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Meng, Xiangmeng
A1 - Putra, Stephen Nugraha
A1 - Bachmann, Marcel
A1 - Rethmier, Michael
T1 - Influence of the spatial laser energy absorption on the molten pool dynamics in high-power laser beam welding
N2 - The spatial laser energy absorption inside the keyhole is decisive for the dynamic molten pool behaviors and the resultant weld properties in high-power laser beam welding (LBW). In this paper, a numerical simulation of the LBW process, considering the 3D transient heat transfer, fluid flow, and keyhole dynamics, is implemented, in which the free surface is tracked by the volume-of-fluid algorithm. The underlying laser-material interactions i.e., the multiple reflections and Fresnel absorption, are considered by an advanced ray-tracing method based on a localized Level-Set strategy and a temperature-dependent absorption coefficient. The laser energy absorption is analyzed from a time-averaged point of view for a better statistical representation. It is found for the first time that a noticeable drop of the time-averaged laser energy absorption occurs at the focus position of the laser beam, and the rest region of the keyhole has relatively homogenous absorbed energy. This unique absorption pattern may lead to a certain keyhole instability and have a strong correlation with the detrimental bulging and narrowing phenomena in the molten pool. The influence of the different focus positions of the laser beam on the keyhole dynamics and molten pool profile is also analyzed and compared. The obtained numerical results are compared with experimental measurements to assure the validity of the proposed model.
T2 - International Congress of Applications of Lasers & Electro-Optics 2023
CY - Chicago, USA
DA - 16.10.2023
KW - Laser beam welding
KW - laser energy absorption
KW - molten pool
KW - keyhole dynamics
KW - numerical modeling
PY - 2023
SP - 1
EP - 8
AN - OPUS4-58754
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Meng, Xiangmeng
A1 - Putra, Stephen Nugraha
A1 - Bachmann, Marcel
A1 - Rethmier, Michael
T1 - The influence of the spatial laser energy absorption on the molten pool dynamics in high power laser beam welding
N2 - The spatial laser energy absorption inside the keyhole is decisive for the dynamic molten pool behaviors and the resultant weld properties in high-power laser beam welding (LBW). In this paper, a numerical simulation of the LBW process, considering the 3D transient heat transfer, fluid flow, and keyhole dynamics, is implemented, in which the free surface is tracked by the volume-of-fluid algorithm. The underlying laser-material interactions i.e., the multiple reflections and Fresnel absorption, are considered by an advanced ray-tracing method based on a localized Level-Set strategy and a temperature-dependent absorption coefficient. The laser energy absorption is analyzed from a time-averaged point of view for a better statistical representation. It is found for the first time that a noticeable drop of the time-averaged laser energy absorption occurs at the focus position of the laser beam, and the rest region of the keyhole has relatively homogenous absorbed energy. This unique absorption pattern may lead to a certain keyhole instability and have a strong correlation with the detrimental bulging and narrowing phenomena in the molten pool. The influence of the different focus positions of the laser beam on the keyhole dynamics and molten pool profile is also analyzed and compared. The obtained numerical results are compared with experimental measurements to assure the validity of the proposed model.
T2 - International Congress of Applications of Lasers & Electro-Optics 2023
CY - Chicago, Illinois, USA
DA - 16.10.2023
KW - Laser beam welding
KW - Laser energy absorption
KW - Molten pool
KW - Keyhole dynamics
KW - Numerical modeling
PY - 2023
AN - OPUS4-58755
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lozano, Daniel
A1 - Bulling, Jannis
A1 - Gravenkamp, Hauke
A1 - Birk, Carolin
T1 - Domain decoupling implementation for efficient ultrasonic wave simulations using scaled boundary finite elements and the mortar method
N2 - We introduce a novel approach that combines the scaled boundary finite element method (SBFEM) with a mortar coupling to enhance the computational modelling of elastic wave propagation and interaction with local features in the ultrasonic range. The key objective is to achieve decoupling between different regions of interest, enabling independent meshes for the zones where waves either propagate or interact with localised discontinuities in the elastic media. This decoupling allows us to exploit the benefits offered by various SBFEM formulations. Thus, we can select the most suitable solution for each specific region. An important concept we emphasise is the differentiation between the near field and far field regions. The near field encompasses zones where the precise representation of small features compared to the wavelength is crucial. At the same time, the far field comprises homogeneous regions where the waves propagate without interactions, eventually radiating towards infinity if the domain is unbounded. By separating these two zones, we can improve the computational performance by employing finer discretisation only where necessary. Furthermore, this decoupling enables the reuse of far field models in parametric analyses, making it highly valuable for scenarios focused particularly on local elastic wave interactions. This approach offers considerable potential in such cases. The modelling technique is validated, and its potential is demonstrated through practical applications.
KW - Computer Science Applications
KW - General Physics and Astronomy
KW - Mechanical Engineering
KW - Mechanics of Materials
KW - Computational Mechanics
PY - 2023
DO - https://doi.org/10.1016/j.cma.2023.116465
SN - 0045-7825
VL - 417
IS - Part A
SP - 1
EP - 21
PB - Elsevier BV
AN - OPUS4-58478
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mishurova, Tatiana
T1 - In-situ hot isostatic pressing combined with x-ray imaging and diffraction of laser powder bed fusion ti-6al-4v
N2 - Hot Isostatic Pressing (HIP) is often introduced to tackle the porosity issue in additively manufactured (AM) materials. For instance, HIP post-processing is recommended to improve fatigue resistance of Laser powder bed fusion (PBF-LB) manufactured parts [1, 2]. Even though HIP cannot completely remove porosity, it significantly decreases the defect population and its average size below the critical threshold value leading to early crack initiation.
In the present study, in-situ investigation of HIP procedure of PBF-LB Ti-6Al-4V parts was carried out to gain further insights into the densification mechanism occurring during HIP. The in-situ observations at high pressure and high temperature are uniquely possible at the PSICHE beamline of the Soleil synchrotron (France), thanks to the Ultrafast Tomography on a Paris-Edinburgh Cell (UToPEC) and the combination of the fast phase-contrast tomography and energy-dispersive diffraction [3, 4]. A detailed methodology was developed to ensure that the correct pressure and temperature were maintained during the experiments.
The results allowed an estimation of the global dentification rate during HIP of PBF-LB Ti-Al-4V material, as well as a detailed quantitative characterization of the influence of pore size and shape on the densification process, thereby understanding the effectiveness of HIP process on different pore categories. After 20 mins, 75% of porosity can be considered as closed or has size below the resolution of the XCT reconstruction. We also observed that the smallest defects showed higher densification rate, while the defect shape did not have significant effect on such rate. The current development of in-situ HIP experiment allows experimental quantification and validation of the simulation work. Ultimately it paves the road to tailoring the HIP procedure for different materials depending on the porosity and microstructure.
T2 - AAMS 2023
CY - Madrid, Spain
DA - 26.09.23
KW - Additive manufacturing
KW - HIP
KW - X-ray computed tomography
PY - 2023
AN - OPUS4-58482
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lohrer, Christian
T1 - Entwicklungen bei der Normung von Explosivstoffen und Pyrotechnik
N2 - Vorstellung der aktuellen Arbeiten im CEN/TC 321 und CEN/TC 212 sowie Ausblick auf wesentliche Themen in den Bereichen zivile Explosivstoffe und pyrotechnische Gegenstände. Des Weiteren wird der Normungsauftrag der KOM für die Pyrotechnik vorgestellt und die damit verbundenen Herausforderungen und Möglichkeiten erläutert.
T2 - 20. Sitzung des Sachverständigenausschusses für explosionsgefährliche Stoffe
CY - Berlin, Germany
DA - 18.09.2023
KW - Explosivstoffe
KW - Pyrotechnik
KW - Normungsauftrag
PY - 2023
AN - OPUS4-58621
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Epperlein, Martin
A1 - Hilgenberg, Kai
A1 - Hellfritz, Benjamin
A1 - Löffler, Frank
T1 - Digitisation of the quality infrastructure - using the example of additive manufacturing
N2 - Rapidly advancing technologies and progressive digitisation are posing challenges to the established quality infrastructure (QI). In response, the key stakeholders of the German QI established the initiative QI-Digital aimed at developing new solutions for modern quality assurance. One of the central use cases herein is quality assurance for additive manufacturing, in which a fully interlinked additive manufacturing process chain is established. The intention is to collect and process data from each production step, allowing for a comprehensive digital view of the physical material flow. Within this process chain, prototypes of digital QI tools like machine readable standards and digital quality certificates are being demonstrated, tested, and evolved. This is complemented by research on the process level, comprising the evaluation and refinement of methods for in-situ and ex-situ quality assurance, as well as algorithms for registration, reduction, and analysis of process data. This paper presents the status, goals, and vision for the QI-Digital use case additive manufacturing.
T2 - Metal Additive Manufacturing Conference 2023
CY - Wien, Austria
DA - 17.10.2023
KW - Additive Manufacturing
KW - Digitalisation
KW - Quality Assurance
PY - 2023
SP - 96
EP - 104
CY - Wien
AN - OPUS4-58628
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Epperlein, Martin
T1 - Digitisation of the quality infrastructure - Using the example of additive manufacturing
N2 - Rapidly advancing technologies and progressive digitisation are posing challenges to the established quality infrastructure (QI). In response, the key stakeholders of the German QI established the initiative QI-Digital aimed at developing new solutions for modern quality assurance. One of the central use cases herein is quality assurance for additive manufacturing, in which a fully interlinked additive manufacturing process chain is established. The intention is to collect and process data from each production step, allowing for a comprehensive digital view of the physical material flow. Within this process chain, prototypes of digital QI tools like machine readable standards and digital quality certificates are being demonstrated, tested, and evolved. This is complemented by research on the process level, comprising the evaluation and refinement of methods for in-situ and ex-situ quality assurance, as well as algorithms for registration, reduction, and analysis of process data. This paper presents the status, goals, and vision for the QI-Digital use case additive manufacturing.
T2 - Metal Additive Manufacturing Conference 2023
CY - Vienna, Austria
DA - 17.10.2023
KW - Additive Manufacturing
KW - Digitalisation
KW - Quality Assurance
PY - 2023
AN - OPUS4-58629
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Epperlein, Martin
T1 - Eine digitale QI für die moderne Produktion: Datenbasierte Qualitätssicherung in der Additiven Fertigung
N2 - Als Beispiel für moderne Produktion ist die additive Fertigung (ugs. „3D-Druck“) bei der Herstellung von hochkomplexen metallischen Bauteilen, bionisch inspiriertem Leichtbau oder Prototypen nicht mehr wegzudenken. Die Qualitätssicherung (QS) von Bauteilen für sicherheitskritische Anwendungen stellt jedoch noch eine Herausforderung dar. Die Additive Fertigung (AM) ist ein vergleichsweise junges und datenintensives Fertigungsverfahren. Daher ist es ideal geeignet, die neuen Werkzeuge einer digitalen Qualitätsinfrastruktur (QI) für die moderne Produktion zu erproben und weiterzuentwickeln.
T2 - 2. QI-Digital Forum
CY - Berlin, Germany
DA - 10.10.2023
KW - Additive Manufacturing
KW - Digitalisation
KW - Quality Assurance
PY - 2023
AN - OPUS4-58630
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Erning, Johann Wilhelm
T1 - “Grabenkorrosion": How scientific debate leads to an solution. and modern failures due to neglection of well described facts
N2 - In the late 1980s, a new type of corrosion appeared in drinking water installations where galvanized steel pipes failed forming a deep groove with no corrosion at the other surfaces. The reason was discussed quite fiercely between failure analysts and material suppliers. In the end the discussion lead to the solution: inductive welded pipes of a certain sulphur content were prone to selective corrosion. The history of the arguments is discussed using old communications between Wilhelm Schwenk and Wolfgang Stichel, who later published the results in a paper unfortunately only I german.
Thus the knowledge got lost and new cases based on the same material problems are observed in application of so-called C-Steel piping systems. Failure cases are shown.
T2 - MTech 2023
CY - Cavtat, Croatia
DA - 02.10.2023
KW - Corrosion
KW - Grabenkorrosion
PY - 2023
SN - 2806-8769
SP - 1
EP - 6
PB - Croatian Society for Heat Treatment and Sufrace Engineering
CY - Zagreb
AN - OPUS4-58521
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kampffmeyer, D.
A1 - Wolters, M.
A1 - Raute, J.
A1 - Biegler, M.
A1 - Rethmeier, Michael
T1 - Laserstrahlauftragschweißen – Einfluss von Schutzgasgemischen auf die Bauteilqualität
N2 - Im Additive Manufacturing Verfahren Directed Energy Deposition (DED) wird bei der Verarbeitung von Werkzeugstahl in der Regel reines Argon als Schutzgas verwendet. Dabei kann die Verwendung von speziellen Schutzgasgemischen, auch bei geringen Anteilen zugemischter Gase, durchaus die Bauteilqualität positiv beeinflussen.
In Vorarbeiten der Messer SE & Co. KGaA zeigte ein gewisser Sauerstoffanteil im Schutzgas die Tendenz, den Flankenwinkel von Schweißspuren beim DED zu verbessern. In der vorliegenden Studie wurde daher detailliert untersucht in wie weit unterschiedliche Schutzgasgemische einen Einfluss auf die Qualität sowie die geometrischen Eigenschaften der additiv gefertigten Strukturen des Werkzeugstahls 1.2709 beim Laser-DED ausüben. Es erfolgten zunächst Testschweißungen in Form von Einzelspuren mit unterschiedlichen Gemischen aus dem Basisschutzgas Argon mit geringen Anteilen verschiedener Gase. Dabei wurde der Einfluss der Zusätze auf die Spurgeometrie und Aufbauqualität untersucht. Auf Basis dieser Vorversuche wurde eine Auswahl vielversprechender Gasgemische getroffen und Detailuntersuchungen in Form von Spuren, Flächen und Quadern unter Zugabe verschiedener Mengen an Zusätzen durchgeführt. Zur Bewertung des Einflusses der Schutzgasbeimengungen wurden der Flankenwinkel, die Porosität und das Gefüge der Proben anhand metallografischer Schliffe untersucht. Es zeigte sich, dass eine Zugabe von geringen Anteilen an Zusätzen zunächst zu einer Vergrößerung des Flankenwinkels im Vergleich zu reinem Argon führt. Mit steigendem Anteil der Gase nimmt dieser Winkel jedoch ab. So kann je nach Menge des zugesetzten Gases eine individuelle Benetzung des aufgetragenen Materials an der Oberfläche erreicht werden. Auch die Porosität ließ sich durch Schutzgasgemische beeinflussen und zeigt ein abweichendes Verhalten im Vergleich zu reinem Argon.
T2 - DVS Congress 2023 Große Schweißtechnische Tagung DVS CAMPUS
CY - Essen, Germany
DA - 11.09.2023
KW - Laser-Pulver-Auftragschweißen
KW - DED-LB
KW - Schutzgas
KW - Additive Fertigung
PY - 2023
SN - 978-3-96144-230-0
SP - 505
EP - 511
PB - DVS-Media
AN - OPUS4-58585
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lemiasheuski, Anton
A1 - Bajer, Evgenia
A1 - Oder, Gabriele
A1 - Göbel, Artur
A1 - Hesse, Rene
A1 - Pfennig, A.
A1 - Bettge, Dirk
T1 - Entwicklung eines automatisierten 3D-Metallographie-Systems und erste Beispiele für die Anwendung in der Gefüge-Analyse
T1 - Development of an automated 3D metallography system and some first application examples in microstructural analysis
N2 - Die klassische Metallographie basiert auf Abbildungen einzelner Schliffebenen und kann auf räumliche Formen und Anordnungen des Gefüges nur bedingt schließen. Die Idee, aus metallographischen Serienschliffen dreidimensionale Gefügestrukturen zu rekonstruieren, ist daher naheliegend und nicht neu. Allerdings ist der Aufwand, in Handarbeit viele Einzel-Schliffe zu präparieren und zu Bildstapeln zusammenzusetzen, sehr hoch und steht einer häufigen Anwendung entgegen.
Deshalb wird an der BAM ein Roboter-gestütztes 3D-Metallographie-System entwickelt, das an einer Schliffprobe die Schritte Präparation und Bildeinzug vollautomatisch mit vielen Wiederholungen ausführt. Die Präparation umfasst Schleifen, Polieren und optional Ätzen der Schlifffläche, der Bildeinzug autofokussierte lichtmikroskopische Aufnahmen bei mehreren Vergrößerungsstufen. Der erhaltene Bildstapel wird anschließend vorverarbeitet, segmentiert und in ein 3D-Modell umgesetzt, das einer mikrotomographischen Aufnahme ähnelt, allerdings mit besserer lateraler Auflösung bei großem Volumen. Im Gegensatz zu tomographischen Verfahren besteht die Möglichkeit der Kontrastierung durch klassische chemische Ätzung. Die Integration eines REMs ist geplant. Bislang durchgeführte Arbeiten verdeutlichen die Möglichkeiten der Darstellung von Heißgas-Korrosionsschichten, Grauguss-Werkstoffen und Keramik-basierten mikroelektronischen Strukturen (Vias).
N2 - Traditional metallography relies on the imaging of individual section planes. However, conclusions as to spatial shapes and microstructural arrangements can only be drawn to a limited extent. The idea to reconstruct three-dimensional microstructures from metallographic serial sections is therefore obvious and not at all new. However, the manual process of preparing a great number of individual sections and assembling them into image stacks is time-consuming and laborious and therefore constitutes an obstacle to frequent use. This is why the Federal Institute for Materials Research and Testing, or BAM for short (Bundesanstalt für Materialforschung und -prüfung), is developing a robot-assisted 3D metallography system performing the tasks of preparation and image acquisition on a metallographic section fully automatically and repeatedly. Preparation includes grinding, polishing and optional etching of the section surface. Image acquisition is performed using a light optical microscope with autofocus at several magnification levels. The obtained image stack is then pre-processed, segmented and converted to a 3D model resembling a microtomographic image, but with a higher lateral resolution when large volumes are sampled. As opposed to tomographic techniques, it is possible to perform traditional chemical etching for contrasting. The integration of a SEM is in the planning stages. Studies conducted so far have demonstrated the possibility of visualizing hot gas corrosion layers, grey cast irons and ceramic-based microelectronic structures (vias).
KW - 3D-Metallographie
KW - Gefügeanalyse
KW - Serienschnitte
KW - Gefügerekonstruktion
KW - 3D metallography
KW - Microstructure analysis
KW - Serial sectioning
KW - Microstrucure reconstruction
PY - 2023
DO - https://doi.org/10.1515/pm-2023-0057
SN - 0032-678X
VL - 60
IS - 10
SP - 676
EP - 691
PB - De Gruyter
CY - Berlin/Boston
AN - OPUS4-58593
LA - mul
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yang, Chunliang
A1 - Yan, Fan
A1 - Meng, Xiangmeng
A1 - Putra, Stephen Nugraha
A1 - Bachmann, Marcel
A1 - Rethmeier, Michael
T1 - Phase-field simulation of the dendrite growth in aluminum alloy AA5754 during alternating current electromagnetic stirring laser beam welding
N2 - Electromagnetic stirring is known to promote material flow, reduce porosity, uniform elements distribution, and refine grain in laser beam welding (LBW), which enhances the applicability of LBW in various industries. In this study, a phase-field model of dendrite growth in AA5754 Al alloy electromagnetic stirring laser beam welding was established. The model considered the thermal electromagnetic Lorentz force resulting from the interaction between the electric field generated by the Seebeck effect and the magnetic field, as well as the temperature gradient and solidification rate of the solidification interface obtained from the computational fluid dynamics electromagnetic stirring LBW model. The variation rules of dendrite growth with different magnetic parameters and effects are analyzed. Comprehensively, the magnetic field promotes the solidification rate, thus promoting interfacial instability and a large magnetic flux density leads to a faster interface instability. The solidification rate as well as the temperature gradient affect the growth rate, and the accelerated growth caused by the so lidification rate with a high frequency and a large magnetic flux density effectively inhibits the slow growth caused by the temperature gradient. The thermal electromagnetic Lorentz force is the main factor for the branch increment at low frequencies, while both thermal electromagnetic Lorentz force and temperature gradient in crease the number of branches at high frequencies. The calculated average branch numbers considering various factors in the stable stage under different magnetic parameters were consistent with the results of the scanning electron microscope tests.
KW - Laser beam welding
KW - Electromagnetic
KW - Aluminum alloys
KW - Phase field method
KW - Dendrite growth
PY - 2024
DO - https://doi.org/10.1016/j.ijheatmasstransfer.2023.124754
SN - 0017-9310
VL - 218
SP - 1
EP - 16
PB - Elsevier Ltd.
AN - OPUS4-58489
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bayerlein, Bernd
T1 - Platform MaterialDigital Core Ontology (PMDco): A Community Driven Mid-Level Ontology in the MSE Domain
N2 - Knowledge representation in the materials science and engineering (MSE) domain is a vast and multi-faceted challenge: Overlap, ambiguity, and inconsistency in terminology are common. Invariant and variant knowledge are difficult to align cross-domain. Generic top-level semantic terminology often is too abstract, while MSE domain terminology often is too specific.
The PMDco is designed in direct support of the FAIR principles to address immediate needs of the global experts community and their requirements. The illustrated findings show how the PMDco bridges semantic gaps between high-level, MSE-specific, and other science domain semantics, how the PMDco lowers development and integration thresholds, and how to fuel it from real-world data sources ranging from manually conducted experiments and simulations as well as continuously automated industrial applications.
T2 - Patents4Science
CY - Berlin, Germany
DA - 05.10.2023
KW - Knowledge Representation
KW - Semantic Interoperability
KW - FAIR data management
KW - Knowledge graph and ontologies
KW - PMD Core Ontology
PY - 2023
AN - OPUS4-58507
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Poka, Konstantin
A1 - Merz, Benjamin
A1 - Epperlein, Martin
A1 - Hilgenberg, Kai
T1 - Integration of the whole digital chain in a unique file for PBF-LB/M: practical implementation within a digital thread and its advantages
N2 - The industrialization of AM is only possible by creating synergy with the tools of Industry 4.0. The system technology of Powder Bed Fusion with Laser beam of Metals (PBF-LB/M) reached a level of high performance in terms of process stability and material spectrum in the past years. However, the digital process chain, starting from CAD via CAM and plant-specific compila-tion of the manufacturing file exhibits media disruptions. The consequence is a loss of metadata. A uniform data scheme of simulation for Design for Additive Manufacturing (DfAM), the PBF-LB/M process itself and quality assurance is currently not realized within industry. There is no entity in the common data flows of the process chains, that enables the integration of these functionalities. As part of the creation of a digital quality infrastructure in the QI-Digital pro-ject, an integration of the CAD/CAM chain is being established. The outcome is a file in an advanced commercially available format which includes all simula-tions and manufacturing instructions. The information depth of this file extends to the level of the scan vectors and allows the automatic optimization and holis-tic documentation. In addition, the KPI for the economic analysis are generated by compressing information into a unique file combined with the application of a digital twin. The implementation and advantages of this solution are demon-strated in a case study on a multi-laser PBF-LB/M system. A build job contain-ing a challenging geometry is thermally simulated, optimized, and manufac-tured. To verify its suitability for an Additive Manufacturing Service Platform (AMSP), the identical production file is transferred to a PBF-LB/M system of another manufacturer. Finally, the achieved quality level of the build job is evaluated via 3D scanning. This evaluation is carried out in the identical entity of the production file to highlight the versatility of this format and to integrate quality assurance data.
T2 - Additive Manufacturing for Products and Applications 2023
CY - Lucerne, Switzerland
DA - 11.09.2023
KW - Laser Powder Bed Fusion
KW - Digital Twin
KW - Data Integrity
KW - Process Chain Integration
KW - Computer Aided Manufacturing
PY - 2023
SN - 978-3-031-42982-8
DO - https://doi.org/10.1007/978-3-031-42983-5_7
SN - 2730-9576
VL - 3
SP - 91
EP - 114
PB - Springer
CY - Cham
AN - OPUS4-58363
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Völker, Christoph
A1 - Moreno Torres, Benjami
A1 - Rug, Tehseen
A1 - Firdous, Rafia
A1 - Zia, Ghezal Ahmad Jan
A1 - Lüders, Stefan
A1 - Lisdero Scaffino, Horacio
A1 - Höpler, Michael
A1 - Böhmer, Felix
A1 - Pfaff, Matthias
A1 - Stephan, Dietmar
A1 - Kruschwitz, Sabine
T1 - Data driven design of alkali-activated concrete using sequential learning
N2 - This paper presents a novel approach for developing sustainable building materials through Sequential Learning. Data sets with a total of 1367 formulations of different types of alkali-activated building materials, including fly ash and blast furnace slag-based concrete and their respective compressive strength and CO2-footprint, were compiled from the literature to develop and evaluate this approach. Utilizing this data, a comprehensive computational study was undertaken to evaluate the efficacy of the proposed material design methodologies, simulating laboratory conditions reflective of real-world scenarios. The results indicate a significant reduction in development time and lower research costs enabled through predictions with machine learning. This work challenges common practices in data-driven materials development for building materials. Our results show, training data required for data-driven design may be much less than commonly suggested. Further, it is more important to establish a practical design framework than to choose more accurate models. This approach can be immediately implemented into practical applications and can be translated into significant advances in sustainable building materials development.
KW - Sustainable building materials
KW - Sequential learning
KW - Data-driven materials design
KW - Alkali-activated building materials
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-584376
UR - https://www.sciencedirect.com/science/article/pii/S095965262302379X
DO - https://doi.org/10.1016/j.jclepro.2023.138221
SN - 0959-6526
SN - 1879-1786
VL - 418
SP - 1
EP - 13
PB - Elsevier
CY - Amsterdam
AN - OPUS4-58437
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bayerlein, Bernd
T1 - News from the working area - Semantic Interoperability
N2 - This presentation provides a comprehensive overview of recent developments and the current status within the Semantic Interoperability work area, with a particular emphasis on the advancements related to the Platform MaterialDigital Core Ontology (PMDco). The presentation will delve into the collaborative and community-supported curation process that has been instrumental in shaping PMDco. Additionally, we will introduce the innovative Ontology Playground, showcasing its role in fostering experimentation and exploration within the realm of ontology development.
T2 - MaterialDigital Vollversammlung
CY - Karlsruhe, Germany
DA - 21.09.2023
KW - Semantic Representation
KW - FAIR data management
KW - Semantic Interoperability
KW - Knowledge graph and ontologies
KW - PMD Core Ontology
KW - MaterialDigital
PY - 2023
AN - OPUS4-58422
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hertwig, Andreas
A1 - Osterwald, Stephan
A1 - Gerhold, Stefan
T1 - Mess- und Prüfverfahren für Schichten und Schichtsysteme - Der DIN-Normausschuss 062-01-61
N2 - Die Funktionalität von modernen technischen Komponenten liegt meist in der Oberfläche und in Beschichtungen. Das Design und die Herstellungsqualität von Beschichtungen ist essenziell für die optischen, elektrischen, mechanischen und chemischen Eigenschaften von Bauteilen, sowie für den Korrosions- und Verschleißschutz. In diesem Gremium bearbeiten wir Normen für die Qualitätssicherung von dünnen Schichten verschiedener Art. Dabei betrachten wir Eigenschaften wie Schichtdicke, Zusammensetzung, Haltbarkeit, Korrosionsbeständigkeit und physikalische Parameter von dünnen Schichten mit sehr vielfältigen Techniken. Neben klassischen Verfahren aus der Galvanik und Schichtmesstechnik, werden dabei auch neuere spektroskopische Verfahren wie Ellipsometrie und THz-Reflektion bedeutend. Unser Gremium ist offen für neue Mitglieder aus der Oberflächen- und Beschichtungsgemeinschaft.
T2 - ZVO Oberflächentage 2023
CY - Berlin, Germany
DA - 13.09.2023
KW - Dünne Schichten
KW - Galvanotechnik
KW - Metallschichten
KW - Messtechnik
PY - 2023
AN - OPUS4-58432
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Scheuschner, Nils
A1 - Heinrichsdorff, F.
A1 - Oster, Simon
A1 - Uhlmann, E.
A1 - Polte, J.
A1 - Gordei, A.
A1 - Hilgenberg, Kai
T1 - In-situ monitoring of the laser powder bed fusion process by thermography, optical tomography and melt pool monitoring for defect detection
N2 - For the wide acceptance of the use of additive manufacturing (AM), it is required to provide reliable testing methods to ensure the safety of the additively manufactured parts. A possible solution could be the deployment of in-situ monitoring during the build process. However, for laser powder bed fusion using metal powders (PBF-LB/M) only a few in-situ monitoring techniques are commercially available (optical tomography, melt pool monitoring), which have not been researched to an extent that allows to guarantee the adherence to strict quality and safety standards.
In this contribution, we present results of a study of PBF-LB/M printed parts made of the nickel-based superalloy Haynes 282. The formation of defects was provoked by local variations of the process parameters and monitored by thermography, optical tomography and melt pool monitoring. Afterwards, the defects were characterized by computed tomography (CT) to identify the detection limits of the used in-situ techniques.
T2 - Lasers in Manufacturing Conference 2023
CY - Munich, Germany
DA - 26.06.2023
KW - Thermography
KW - Optical tomography
KW - Melt-pool-monitoring
KW - Laser powder bed fusion
KW - Haynes 282
KW - Additive Manufacturing
PY - 2023
UR - https://www.wlt.de/lim2023-proceedings/system-engineering-and-process-control
SP - 1
EP - 10
AN - OPUS4-58466
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bettge, Dirk
A1 - Schmies, Lennart
T1 - Die Fraktographische Online-Datenbank der AG Fraktographie – Entwicklungsstand und weitere Planung
N2 - Vortrag zum aktuellen Stand der fraktographischen online-Datenbank. Darstellung des AGM/DVM Gemeinschaftsausschusses REM in der Materialforschung und seiner Arbeitsgruppen Fraktographie, EBSD und 2D/3D-Prüfung. Ziele und Inhalte der fraktographischen Datenbank, Aufruf zum Mitmachen. Durchführung von Vergleichsversuchen, Entwicklung einer fraktographischen Symbolik, Ringversuch, Vorhaben iFrakto mit Entwicklung einer KI-gestützten Bruchflächenanalyse.
T2 - Metallographietagung 2023
CY - Leoben, Austria
DA - 13.09.2023
KW - Fraktographie
KW - Machine Learning
KW - Datenbank
PY - 2023
AN - OPUS4-58467
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pech May, Nelson Wilbur
A1 - Tabasco-Novelo, Carolina
A1 - Quintana, Patricia
A1 - Rodriguez-Gattorno, Geonel
A1 - Alvarado-Gil, Juan J.
T1 - Evidence of a Thermal Diffusivity Gap in Sintered Li–Co–Sb–O Solid Solutions
N2 - In this work, the thermal properties of ternary Li₃ₓCo₇₋₄ₓSb₂₊ₓO₁₂ solid solutions are studied for different concentrations in the range 0 ≤ x ≤ 0.7. Samples are elaborated at four different sintering temperatures: 1100, 1150, 1200 and 1250 °C. The effect of increasing the content of Li⁺ and Sb⁵⁺, accompanied by the reduction of Co²⁺, on the thermal properties is studied. It is shown that a thermal diffusivity gap, which is more pronounced for low values of x, can be triggered at a certain threshold sintering temperature (around 1150 °C in this study). This effect is explained by the increase of contact area between adjacent grains. Nevertheless, this effect is found to be less pronounced in the thermal conductivity. Moreover, a new framework for heat diffusion in solids is presented that establishes that both the heat flux and the thermal energy (or heat) satisfy a diffusion equation and therefore highlights the importance of thermal diffusivity in transient heat conduction phenomena.
KW - General Chemical Engineering
KW - General Chemistry
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593248
DO - https://doi.org/10.1021/acsomega.2c07557
SN - 2470-1343
VL - 8
IS - 8
SP - 7808
EP - 7815
PB - American Chemical Society (ACS)
CY - Washington, DC
AN - OPUS4-59324
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schmies, Lennart
A1 - Botsch, B.
A1 - Le, Q.-H.
A1 - Yarysh, A.
A1 - Sonntag, U.
A1 - Hemmleb, M.
A1 - Bettge, Dirk
T1 - Classification of fracture characteristics and fracture mechanisms using deep learning and topography data
T1 - Klassifikation von Bruchmerkmalen und Bruchmechanismen mittels Deep Learning und unter Verwendung von Topographiedaten
N2 - In failure analysis, micro-fractographic analysis of fracture surfaces is usually performed based on practical knowledge which is gained from available studies, own comparative tests, from the literature, as well as online databases. Based on comparisons with already existing images, fracture mechanisms are determined qualitatively. These images are mostly two-dimensional and obtained by light optical and scanning electron imaging techniques. So far, quantitative assessments have been limited to macrocopically determined percentages of fracture types or to the manual measurement of fatigue striations, for example. Recently, more and more approaches relying on computer algorithms have been taken, with algorithms capable of finding and classifying differently structured fracture characteristics. For the Industrial Collective Research (Industrielle Gemeinschaftsforschung, IGF) project “iFrakto” presented in this paper, electron-optical images are obtained, from which topographic information is calculated. This topographic information is analyzed together with the conventional 2D images. Analytical algorithms and deep learning are used to analyze and evaluate fracture characteristics and are linked to information from a fractography database. The most important aim is to provide software aiding in the application of fractography for failure analysis. This paper will present some first results of the project.
N2 - Die mikrofraktographische Analyse von Bruchflächen wird in der Schadensanalyse meist auf der Basis von Erfahrungswissen vorgenommen, welches aus vorliegenden Untersuchungen, eigenen Vergleichsversuchen und aus der Literatur und online Datenbanken stammt. Durch Vergleiche mit bereits vorliegenden Bildern werden qualitativ Bruchmechanismen ermittelt. Grundlage dafür sind zumeist zweidimensionale Aufnahmen aus licht- und elektronenoptischen Verfahren. Quantitative Aussagen beschränken sich bislang beispielsweise auf makroskopische Anteile von Bruchmechanismen oder die manuelle Ausmessung von Schwingstreifen. In jüngerer Zeit gibt es vermehrt Ansätze, Computer-Algorithmen einzusetzen, die in der Lage sind, unterschiedlich strukturierte Bruchmerkmale zu finden und zu klassifizieren. Im hier vorgestellten IGF-Vorhaben „iFrakto“ werden elektronenoptische Aufnahmen erzeugt und daraus Topographie-Informationen berechnet. Diese gewonnenen Topographie-Informationen werden zusammen mit den klassischen 2D-Bildern ausgewertet. Analytische Algorithmen und Deep Learning werden eingesetzt, um Bruchmerkmale zu analysieren, zu bewerten und mit Informationen aus einer fraktographischen Datenbank zu verknüpfen. Wichtigstes Ziel ist die Bereitstellung von Software zur Unterstützung der Fraktographie in der Schadensanalyse. In diesem Beitrag werden erste Ergebnisse des Vorhabens vorgestellt.
KW - Fractography
KW - Deep Learning
KW - Classification
PY - 2023
DO - https://doi.org/10.1515/pm-2022-1008
SN - 0032-678X
VL - 60
IS - 2
SP - 76
EP - 92
PB - De Gruyter
AN - OPUS4-56962
LA - mul
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ghafafian, Carineh
A1 - Trappe, Volker
ED - Vassilopoulos, A. P.
ED - Michaud, V.
T1 - Fully-reversed fatigue behavior of scarf joint repairs for wind turbine blade shell applications
N2 - To enable a quick and cost-effective return to service for wind turbine blades, localized repairs can be executed by technicians in the field. Scarf repairs, shown to be highly efficient with a smooth load transition across angled joint walls and a restored aerodynamic profile, are the focus of this work. The failure mechanisms of these structures were examined under quasi-static tensile and fully-reversed cyclic loading. While the scarf ratio was held constant at 1:50, the repair layup was varied between large-to-small and small-to-large. The effect of the presence of resin pockets and the fiber orientation mismatch between parent and repair material on the restored strength of BIAX ±45° glass fiber reinforced polymer scarf joint structures was studied.
T2 - 20th European Conference on Composite Materials
CY - Lausanne, Switzerland
DA - 26.06.2022
KW - Fatigue
KW - Scarf repairs
KW - Glass fiber reinforced polymers
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569646
UR - https://infoscience.epfl.ch/record/298799
SN - 978-2-9701614-0-0
VL - Vol. 5 - Applications and structures
SP - 195
EP - 201
PB - Composite Construction Laboratory (CCLab)
CY - Lausanne
AN - OPUS4-56964
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zhang, X.
A1 - Shi, L.
A1 - Wu, C.
A1 - Yang, Chunliang
A1 - Gao, S.
T1 - Multi-phase modelling of heat and mass transfer during Ti/Al dissimilar friction stir welding process
N2 - Friction stir welding (FSW) has the capacity to join the Al/Ti dissimilar structures with superior mechanical properties. The microstructures and mechanical characteristics of Al/Ti dissimilar FSW joints are determined by the heat and mass transfer during the welding process. However, a quantitative study of the Al/Ti dissimilar FSW process is lacking. Therefore, using the computational fluid dynamics (CFD) and volume of fluid (VOF) approach, a multi-phase model was constructed for quantitatively analyzing the heat and mass transfer behaviour in dissimilar FSW of TC4 titanium alloy and AA2024-T4 aluminium alloy. The mixed material was treated as a functionally graded material (FGM) to compute the thermophysical characteristics at the weld nugget zone (WNZ). Due to the vast disparity in the thermophysical characteristics of aluminum and titanium alloy, the temperature field in Al/Ti dissimilar FSW was severely asymmetric. The temperature of titanium alloy on the advancing side (AS) was higher than that of aluminium alloy on the retreating side (RS) at the same distance from the tool centre line near the tool shoulder, but it was lower than that of aluminium alloy on the RS without the influence of the shoulder. Due to the high flow stress of titanium alloy, plastic material flow mostly occurred on the RS of aluminium alloy in the Al/Ti dissimilar FSW, with its percentage exceeding 80%. This model was validated by experiment results.
KW - Dissimilar friction stir welding
KW - Al/Ti dissimilar joints
KW - Temperature distribution
KW - Heat generation
KW - Plastic material flow
PY - 2023
DO - https://doi.org/10.1016/j.jmapro.2023.03.037
SN - 2212-4616
VL - 94
SP - 240
EP - 254
PB - Elsevier Ltd.
AN - OPUS4-57265
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Cysne Barbosa, Ana Paula
A1 - Azevedo do Nascimento, Allana
A1 - Pavasarytė, Lina
A1 - Trappe, Volker
A1 - Melo, D.
T1 - Effect of addition of thermoplastic self-healing agent on fracture toughness of epoxy
N2 - Self-healing agents have the potential to restore mechanical properties and extend service life of composite materials. Thermoplastic healing agents have been extensively investigated for this purpose in epoxy matrix composites due to their strong adhesion to epoxy and their ability to fill in microcracks. One of the most
investigated thermoplastic additives for this purpose is poly(ethylene-co-methacrylic acid) (EMAA). Despite the ability of thermoplastic healing agents to restore mechanical properties, it is important to assess how the addition of thermoplastic healing agents affect properties of the original epoxy material. In this work, EMAA was added to epoxy resin and the effect of the additive on fracture toughness of epoxy was evaluated. Results indicate that although added in low concentrations, EMAA can affect fracture toughness.
T2 - 6th Brazilian Conference on Composite Materials
CY - Tiradentes, Minas Gerais, Brazil
DA - 14.08.2022
KW - Epoxy
KW - Self-healing
KW - Thermoplastic
KW - Fracture
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-572707
SN - 978-65-00-49386-3
DO - https://doi.org/10.29327/566492
SN - 2316-1337
SP - 219
EP - 222
AN - OPUS4-57270
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Matamoros-Veloza, A.
A1 - Stawski, Tomasz
A1 - Vargas, S.
A1 - Neville, A.
T1 - Study of a Local Structure at the Interface between Corrosion Films and Carbon Steel Surface in Undersaturated CO2 Environments
N2 - Industries transporting CO2 gas-saturated fluids have infrastructures made of carbon steel. This is a good material with great mechanical properties but prone to corrosion and potential failure. Corrosion in sweet environments involves the formation of FeCO3 as a corrosion film, which is recognized to play a protective role under certain conditions. This work on the dissolution of corrosion films in sweet environments, under acidic and undersaturated conditions, demonstrates that the effects on the integrity of steel are far more significant than the damage observed on the surface of the corrosion film. Our results prove that dissolution of FeCO3 involved the presence of an amorphous phase, the intermediate formation of FeCl2 or FeCl+, and the presence of a phase with short distance atom–atom correlations. The amorphous phase was identified as a mixture of retained γ-Fe and Fe3C. Partially broken α-Fe and Fe3C structures were identified to prove the damage on the material, confirming the interface zone without evident damage on the corrosion film. Dissolution affected both the α-Fe and FeCO3, with the lattice [102̅] from the FeCO3 crystalline structure being the fastest to dissolve. The damage of steel at the molecular scale was evident at the macroscale with pit depths of up to 250 μm. The impact on the integrity of steel can be, therefore, more drastic than frequently reported in industrial operations of CO2 transport industries that use cleaning procedures (e.g., acid treatment, pigging) as part of their operational activities.
KW - Steel
KW - Corrosion
KW - Siderite
KW - Diffraction
KW - Pair distribution function
KW - Synchrotron
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-572156
DO - https://doi.org/10.1021/acsomega.2c07631
SN - 2470-1343
VL - 8
IS - 9
SP - 8497
EP - 8504
PB - ACS
AN - OPUS4-57215
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Chambers, Aaron
T1 - Synthesis of ZIF nanoparticles with functionalisation towards effective composite formation
N2 - A presentation on functionalising ZIF-8 nanoparticles for composite formation. Characterisation data for the nanoparticles is shown.
T2 - Materials Chemistry Seminar
CY - Online meeting
DA - 23.02.23
KW - MOF composite
KW - Nanoparticles
KW - ZIF-8
PY - 2023
AN - OPUS4-57210
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Winterkorn, René
T1 - WAAM dickwandiger Bauteile aus höherfesten AL-MG-SI Legierungen
N2 - Das Wire and Arc Additive Manufacturing (WAAM) ist dank hoher erreichbarer Aufbauraten prädestiniert für die Fertigung großvolumiger Bauteile. Dabei ist auf die Wirkmechanismen zwischen Prozessparametern und den daraus resultierenden mechanisch-technologischen Eigenschaften zu achten. Dies gilt insbesondere für die Fertigung dickwandiger Bauteile aus Al-Mg-Si-Aluminiumlegierungen, die eine hohe Anfälligkeit gegenüber Erstarrungsrissen und wasserstoffinduzierter Porosität aufweisen. Der Einfluss der Prozessparameter und des resultierenden Temperaturregimes auf die Bauteilqualität wurde durch die Analyse der Größe und Verteilung von Poren sowie der resultierenden Festigkeit untersucht. Darüber hinaus wurde der Einfluss einer Wärmenachbehandlungsstrategien auf das Festigkeitsverhalten analysiert.
T2 - Additive Fertigung – Werkstoffe – Prozesse – Wärmebehandlung 2022
CY - Bremen, Germany
DA - 29.06.2022
KW - WAAM
KW - AlMgSi Legierungen
KW - Wärmenachbehandlung
KW - Mechanische Eigenschaften
PY - 2022
AN - OPUS4-56672
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Yildirim, Arda
A1 - Krause, Christina
A1 - Zorn, R.
A1 - Schönhals, Andreas
T1 - Multiple glassy dynamics of a homologous series of triphenylene-based columnar liquid crystals – A study by broadband dielectric spectroscopy, advanced calorimetry and Neutron Scattering
N2 - Hexakis(n-alkyloxy)triphenylene) (HATn) consisting of an aromatic triphenylene core and alkyl side chains are model discotic liquid crystal (DLC) systems forming a columnar mesophase. In the mesophase, the molecules of HATn self-assemble in columns, which has one-dimensional high charge carrier mobility along the columns. Here, a homologous series of HATn with different length of the alkyl chain (n=5,6,8,10,12) is investigated using differential scanning calorimetry (DSC), broadband dielectric spectroscopy (BDS) and advanced calorimetric techniques including fast scanning calorimetry (FSC) and specific heat spectroscopy (SHS). The investigation of the phase behavior was done utilizing DSC experiments and the influence of the alkyl chain length on the phase behavior was revealed. By the dielectric investigations a γ-relaxation due to localized fluctuations as well as two glassy dynamics the αcore and αalkyl relaxation were observed in the temperature range of the plastic crystalline phase. Moreover, the observed glassy dynamics were further studied employing advanced calorimetry. All observed relaxation processes are attributed to the possible specific molecular fluctuations and discussed in detail. From the results a transition at around n=8 from a rigid constrained (n=5,6) to a softer system (n=10,12) on a molecular lenght scale was revealed with increasing alkyl chain length. A counterbalance of two competing effects of a polyethylene like behavior of the alkyl chains in the intercolumnar domains and self-organized confinement is discussed in the context of a hindered glass transition. The results were confirmed by in- and quasielastic neutron scattering
T2 - Confit 2022
CY - Grenoble, France
DA - 10.10.2022
KW - Glassy Dynamics
KW - Discotic Liquid Crystals
PY - 2022
AN - OPUS4-56661
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Völker, Christoph
A1 - Kruschwitz, Sabine
T1 - Accelerating the search for sustainable concretes with AI
N2 - With 8% of man-made CO2 emissions, cement production is an important driver of the climate crisis. By using alkali-activated binders, part of the energy-intensive clinker production process can be dispensed. However, as numerous raw materials are involved in the manufacturing process here, the complexity of the materials increases by orders of magnitude. Finding a properly balanced binder formulation is like looking for a needle in a haystack. We have shown for the first time that artificial intelligence (AI)-based optimization of alkali-activated binder formulations can significantly accelerate research.
The "Sequential Learning App for Materials Discovery" (SLAMD) aims to accelerate practice transfer. With SLAMD, materials scientists have low-threshold access to AI through interactive and intuitive user interfaces. The value added by AI can be determined directly. For example, the CO2 emissions saved per ton of cement can be determined for each development cycle: the more efficient the AI optimization, the greater the savings.
Our material database already includes more than 120,000 data points of alternative binders and is constantly being expanded with new parameters. We are currently driving the enrichment of the data with a life cycle analysis of the building materials.
Based on a case study we show how intuitive access to AI can drive the adoption of techniques that make a real contribution to the development of resource-efficient and sustainable building materials of the future and make it easy to identify when classical experiments are more efficient.
T2 - fib International Congress
CY - Oslo, Norway
DA - 12.06.2022
KW - Machine Learning
KW - Materials Design
KW - Sequential Learning
KW - Materials Discovery
KW - Concrete
PY - 2022
AN - OPUS4-56635
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Völker, Christoph
A1 - Moreno Torres, Benjami
T1 - SLAMD-FIB-Case-Study
N2 - With 8% of man-made CO2 emissions, cement production is an important driver of the climate crisis. By using alkali-activated binders part of the energy-intensive clinker production process can be dispensed with. However, because numerous chemicals are involved in the manufacturing process here, the complexity of the materials increases by orders of magnitude. Finding a properly balanced cement formulation is like looking for a needle in a haystack. We have shown for the first time that artificial intelligence (AI)-based optimization of cement formulations can significantly accelerate research. The „Sequential Learning App for Materials Discovery“ (SLAMD) aims to accelerate practice transfer. With SLAMD, materials scientists have low-threshold access to AI through interactive and intuitive user interfaces. The value added by AI can be determined directly. For example, the CO2 emissions saved per ton of cement can be determined for each development cycle: the more efficient the AI optimization, the greater the savings. Our material database already includes more than 120,000 data points of alternative cements and is constantly being expanded with new parameters. We are currently driving the enrichment of the data with a life cycle analysis of the building materials. Based on a case study we show how intuitive access to AI can drive the adoption of techniques that make a real contribution to the development of resource-efficient and sustainable building materials of the future and make it easy to identify when classical experiments are more efficient.
KW - Alkali activated concrete
KW - Concrete
PY - 2022
UR - https://github.com/BAMcvoelker/SLAMD-FIB-Case-Study#slamd-fib-case-study
PB - GitHub
CY - San Francisco, CA, USA
AN - OPUS4-56637
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Völker, Christoph
T1 - Discovering climate-friendly building materials with AI
N2 - High greenhouse gas emissions from the production of building materials are a major contributor to the current climate crisis. However, developing alternative building materials is complex. Traditional laboratory methods are reaching their limits. Artificial intelligence, on the other hand, can give research a new dynamic.
Novel materials are usually developed manually in the laboratory rather than on a computer. This makes the processes time-consuming, difficult and expensive. With the app SLAMD (Sequential Learning App for Materials Discovery), materials researchers can explore the potential of artificial intelligence to speed up materials research and easily apply AI in the lab. The app was developed by our team at the Federal Institute for Materials Research and Testing (BAM) led by Prof. Sabine Kruschwitz together with a team in the Department of Building Materials and Construction Chemistry at TU Berlin led by Prof. Dietmar Stephan.
It uses material composition and characterization data to predict ideal material candidates. It can be used to optimize many material properties simultaneously and even incorporates database information such as carbon footprint, material cost or resource availability. Unlike the usual data-intensive AI methods, SLAMD optimally integrates existing knowledge and human feedback, and provides numerous decision support tools to precisely navigate complex scientific knowledge processes towards success.
In this talk, we will present some case studies where we were able to find suitable advanced materials in a few months instead of several years. We will talk about the challenges we overcame and the future potential we see for this approach to developing the green materials of the future.
T2 - Chemometrics meets Artificial Intelligence
CY - Berlin, Germany
DA - 01.04.2022
KW - Machine Learning
KW - Materials Informatics
KW - Sequential Learning
KW - Alkali activated concrete
PY - 2022
AN - OPUS4-56638
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - VIDEO
A1 - Völker, Christoph
T1 - Accelerating the search for sustainable concretes with AI
N2 - With 8% of man-made CO2 emissions, cement production is an important driver of the climate crisis. By using alkali-activated binders, part of the energy-intensive clinker production process can be dispensed. However, as numerous raw materials are involved in the manufacturing process here, the complexity of the materials increases by orders of magnitude. Finding a properly balanced binder formulation is like looking for a needle in a haystack. We have shown for the first time that artificial intelligence (AI)-based optimization of alkali-activated binder formulations can significantly accelerate research.
The "Sequential Learning App for Materials Discovery" (SLAMD) aims to accelerate practice transfer. With SLAMD, materials scientists have low-threshold access to AI through interactive and intuitive user interfaces. The value added by AI can be determined directly. For example, the CO2 emissions saved per ton of cement can be determined for each development cycle: the more efficient the AI optimization, the greater the savings.
Our material database already includes more than 120,000 data points of alternative binders and is constantly being expanded with new parameters. We are currently driving the enrichment of the data with a life cycle analysis of the building materials.
Based on a case study we show how intuitive access to AI can drive the adoption of techniques that make a real contribution to the development of resource-efficient and sustainable building materials of the future and make it easy to identify when classical experiments are more efficient.
KW - Materials informatics
KW - Materials design
KW - Alkali activated concrete
KW - Machine learning
PY - 2022
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-56639
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ghafafian, Carineh
A1 - Trappe, Volker
T1 - Prolonging structural integrity—Fatigue of scarf repairs for wind turbine blade shell applications
N2 - The influence of scarf repair variables on the mechanical properties of glass fiber reinforced polymer sandwich structures is examined for the application of wind turbine blade shell repairs. Reference shell specimens are tested under fully-reversed cyclic loading to understand the fatigue behavior of the sub-component structure within a range of in-service loads, to which shell specimens with a scarf joint repair are compared. A fatiguesuperior repair material is shown to improve the fatigue behavior of the repaired structures compared to the reference specimens. In separating layup and geometry, damage development is examined on the subcomponent scale for a structural understanding of a scarf repair using in-situ digital image correlation-based strain field measurements as well as passive thermography. Within scarf repair variables, the geometry is shown to play a larger role than layup in the fatigue performance of the repaired structure.
KW - Polymer–matrix composites
KW - Fatigue
KW - Joints/joining
PY - 2023
DO - https://doi.org/10.1016/j.compositesa.2022.107419
SN - 1359-835X
VL - 167
SP - 1
EP - 11
PB - Elsevier Ltd.
AN - OPUS4-56942
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bonse, Jörn
T1 - Laser-induced periodic surface structures: mechanisms, applications, and unsolved problems
N2 - Laser-induced Periodic Surface Structures (LIPSS, ripples) are a universal phenomenon and can be generated in a contactless, single-step process on almost any type of solid upon irradiation with intense laser pulses. They represent a (quasi-)periodic modulation of the surface topography in the form of a linear grating and are typically formed in a “self-ordered” way in the focus of a laser beam. Thus, they are often accompanying laser material processing applications. The structural sizes of LIPSS typically range from several micrometers down to less than 100 nanometers – far beyond the optical diffraction limit – while their orientations exhibit a clear correlation with the local polarization direction of the laser radiation.
From a theoretical point of view, a controversial debate has emerged during the last decades, whether LIPSS originate from electromagnetic effects (seeded already during the laser irradiation) – or whether they emerge from matter-reorganization processes (distinctly after the laser irradiation). From a practical point of view, however, LIPSS represent a simple and robust way for the nanostructuring of solids that allows creating a wide range of different surface functionalities featuring applications in optics, tribology, medicine, energy technologies, etc.
This presentation reviews the currently existent theories of LIPSS. A focus is laid on the historic development of the fundamental ideas behind the LIPSS, their corresponding mathematical descriptions and numerical implementations, along with a comparison and critical assessment of the different approaches.
Fourth generation light sources, namely short wavelength, short pulse free electron lasers (FELs) are offering new and fascinating possibilities to resolve laser-induced structure formation at surfaces on the sub-micrometer to nanometer length scale and in temporal regimes ranging from picoseconds to several nanoseconds with sub-picosecond resolution. This unique spatio-temporal resolution allows to reveal early signatures of coherent/plasmonic electromagnetic scattering effects followed by the excitation of hydrodynamic capillary waves – providing new insights to the above-mentioned debate.
Finally, some unsolved scientific problems related to LIPSS are identified and the pending technological limitations are discussed. While the currently available laser and scanner technology already allows large area surface processing with rates at the m2/min level, industrial applications of LIPSS are sometimes limited by the complex interplay between the nanoscale surface topography and the specific surface chemistry. This typically manifests in difficulties to control the processing of LIPSS and in limitations to ensure the long-term stability of the created surface functions. Strategies for overcoming such limitations are outlined.
T2 - Institutskolloquium des Leibniz-Instituts für Oberflächenmodifizierung
CY - Leipzig, Germany
DA - 02.02.2023
KW - Laser-induced periodic surface structures (LIPSS)
KW - Surface functionalization
KW - Industrial applications
KW - Femtosecond laser
PY - 2023
AN - OPUS4-56949
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Das, P.
A1 - Chakraborty, Gouri
A1 - Roeser, J.
A1 - Vogl, S.
A1 - Rabeah, J.
A1 - Thomas, A.
T1 - Integrating Bifunctionality and Chemical Stability in Covalent Organic Frameworks via One-Pot Multicomponent Reactions for Solar-Driven H2O2 Production
N2 - Multicomponent reactions (MCRs) can be used to introduce different functionalities into highly stable covalent organic frameworks (COFs). In this work, the irreversible three-component Doebner reaction is utilized to synthesize four chemically stable quinoline-4-carboxylic acid DMCR-COFs (DMCR-1−3 and DMCR-1NH) equipped with an acid−base bifunctionality. These DMCR-COFs show superior photocatalytic H2O2 evolution (one of the most important industrial oxidants) compared to the imine COF analogue (Imine-1). This is achieved with sacrificial oxidants but also in pure water and under an oxygen or air atmosphere. Furthermore, the DMCR-COFs show high photostability, durability, and recyclability. MCR-COFs thus provide a viable materials’ platform for solar to chemical energy conversion.
KW - Reactions
KW - Bifunctionality
KW - Postsynthetic modification
KW - Multicomponent
PY - 2022
DO - https://doi.org/10.1021/jacs.2c11454
SN - 0002-7863
VL - 145
IS - 5
SP - 2975
EP - 2984
PB - ACS Publications
AN - OPUS4-56922
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Trappe, Volker
A1 - Sachs, Patrick
ED - Vassilopoulos, A. P.
ED - Michaud, V.
T1 - Dynamic mechanical analysis of epoxy-matrix cross linking measured in-situ using an elastomer container
N2 - A new patented dynamic mechanical analysis (DMA) is presented, where the tensile, bending- or torsional stiffness of a media can be characterized in-situ during the phase transition from liquid to solid. An epoxy system, e.g. Hexion L285/H287, is filled into an elastomer container, such as a silicone tube. This can be mounted into a conventional OMA and, based on a linear viscoelastic approach, the storage modulus (E';G'), the loss modulus (E'';G'') and the loss angle tan(δ) can be measured at constant temperature as a function of time in order to investigate the liquid to sol-gel to solid transition. With this new method, the stiffness increase as a result of the cure process can be directly measured more precisely than with a rheometer in a shear plate set-up, because using an elastomer container gives a defined cross section for calculating the Young's modulus.
T2 - 20th European Conference on Composite Materials
CY - Lausanne, Switzerland
DA - 26.06.2022
KW - Cross linking
KW - Dynamic mechanical analysis (DMA)
KW - Thermoset polymers
KW - Cure process
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569651
UR - https://infoscience.epfl.ch/record/298799
SN - 978-2-9701614-0-0
VL - Vol. 5 - Applications and structures
SP - 181
EP - 186
PB - Composite Construction Laboratory (CCLab)
CY - Lausanne
AN - OPUS4-56965
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Azevedo do Nascimento, A.
A1 - Trappe, Volker
A1 - Diniz Melo, J. D.
A1 - Cysne Barbosa, A. P.
T1 - Fatigue behavior of self-healing glass fiber/epoxy composites with addition of poly (ethylene-co-methacrylic acid) (EMAA)
N2 - The interest in repair technologies for polymer composites has increased significantly over the last decades, due to the growing use of these materials in structural applications. In this study, poly (ethylene-co-methacrylic acid) (EMAA) was used as self-healing agent to glass fiber/epoxy composite. Materials with EMAA contents of 2 wt% and 5 wt% were manufactured using Resin Transfer Molding (RTM) and the effects of the healing agent on the properties were investigated using tensile tests and Dynamic Mechanical Analysis (DMA). Results show slight variation of properties, which was more pronounced as the content of EMAA increased. In addition, the healing efficiency was investigated through fatigue tests and the addition of higher content of EMAA increased the number of cycles to failure after the healing activation cycle.
KW - Fatigue
KW - Glass fiber-epoxy composites
KW - Self-healing
KW - Smart materials
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569661
DO - https://doi.org/10.1016/j.polymertesting.2022.107863
SN - 0142-9418
VL - 117
SP - 1
EP - 10
PB - Elsevier Ltd.
AN - OPUS4-56966
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lunkenheimer, P.
A1 - Loidl, A.
A1 - Riechers, Birte
A1 - Zaccone, A.
A1 - Samwer, K.
T1 - Thermal expansion and the glass transition
N2 - Melting is well understood in terms of the Lindemann criterion, which
essentially states that crystalline materials melt when the thermal vibrationsof their atoms become so vigorous that they shake themselves free of the binding forces. This picture does not necessarily have to hold for glasses, where the nature of the solid–liquid cross-over is highly debated. The Lindemann criterion implies that the thermal expansion coefficients of crystals are inversely proportional to their melting temperatures. Here we find that, in contrast, the thermal expansion coefficient of glasses decreases more strongly with increasing glass temperature, which marks the liquid–solid cross-over in this material class. However, this proportionality returns when the thermal expansion coefficient is scaled by the fragility, a measure of particle cooperativity. Therefore, for a glass to become liquid, it is not sufficient to simply overcome the interparticle binding energies.
Instead, more energy must be invested to break up the typical cooperative particle network that is common to glassy materials. The thermal expansion coefficient of the liquid phase reveals similar anomalous behaviour and is universally enhanced by a constant factor of approximately 3. These universalities allow the estimation of glass temperatures from thermal expansion and vice versa.
KW - Glass transition
KW - Lindemann criterion
KW - Thermal expansion
KW - Glass
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-570267
DO - https://doi.org/10.1038/s41567-022-01920-5
SN - 1745-2473
SP - 1
EP - 7
PB - Nature Publishing Group
CY - London
AN - OPUS4-57026
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zhang, Kun
A1 - Pan, L.
A1 - Li, J.
A1 - Lin, C.
T1 - What is the mechanism of the fiber effect on the rheological behavior of cement paste with polycarboxylate superplasticizer?
N2 - Compared with most common construction materials, fiber reinforced cementitious materials are well known to exhibit better physical, working and mechanical properties. In this study, three fibers were selected: polypropylene fiber (PPF) and polyvinyl alcohol fiber (PVAF), which represented synthetic fibers, and sisal fiber (SF), which represented natural fibers. Effects of these fibers on the flowability, rheological properties, and adsorption behavior of the cement paste with polycarboxylate superplasticizer (PCE) were investigated. Furthermore, the above experimental results were verified by measuring the contact angle of the fiber with water and PCE solution and the apparent morphology of the fiber. Results revealed that the addition of fibers significantly reduces the fluidity of the cement paste, while the yield stress and plastic viscosity of the cement paste increase with the addition of fibers. From the contact angle and scanning electron microscope, the surface of SF was relatively rough, and the contact angle of SF with water or PCE solution was the smallest. It can be concluded that the plant fiber has a significant influence on the fluidity and rheology of cement paste.
KW - Cement paste
KW - Polycarboxylate superplasticizer
KW - Polypropylene fiber
KW - Polyvinyl alcohol fiber
KW - Sisal fiber
KW - Rheological property
KW - Fluidity
KW - Adsorption
PY - 2021
DO - https://doi.org/10.1016/j.conbuildmat.2021.122542
SN - 0950-0618
VL - 281
SP - 1
EP - 11
PB - Elsevier
CY - Amsterdam
AN - OPUS4-56893
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Krüger, Jörg
A1 - Bonse, Jörn
T1 - Editorial: Special Issue “Advanced Pulse Laser Machining Technology"
N2 - “Advanced Pulse Laser Machining Technology” is a rapidly growing field that can be tailored to special industrial and scientific applications. This is significantly driven by the availability of high-repetition-rate laser sources and novel beam delivery concepts.
KW - Editorial
KW - Pulse Laser
KW - Laser Machining
KW - Ultrashort laser pulses
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568410
DO - https://doi.org/10.3390/ma16020819
SN - 1996-1944
VL - 16
IS - 2
SP - 1
EP - 4
PB - MDPI
CY - Basel
AN - OPUS4-56841
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
ED - Krüger, Jörg
ED - Bonse, Jörn
T1 - Special Issue "Advanced Pulse Laser Machining Technology"
N2 - Advanced Pulse Laser Machining Technology is a rapidly growing field to tailor special industrial and scientific applications. This is significantly driven by the availability of high-repetition rate laser sources and novel beam delivery concepts.
This Special Issue focuses on developments in areas of surface and volume laser material processing, including spatial and temporal beam shaping, Bessel-beam dicing, direct laser interference patterning (DLIP), laser-induced forward transfer (LIFT), pulse burst machining, waveguide writing, and two-photon polymerization. Additionally, limitations of modern laser processing caused by failure of laser optics or unwanted secondary hazards like X-ray emission are addressed.
Here, we would like to attract contributors from industry and academics. This Special Issue shall bundle original research and review articles of the latest achievements.
KW - Advanced ultrashort-laser technology
KW - Bessel-beam laser dicing
KW - Direct laser interference patterning (DLIP)
KW - High-repetition rate ultrafast laser processing
KW - Laser-induced forward transfer (LIFT)
KW - X-ray hazards during ultrafast laser processing
KW - Volume processing, waveguide writing
KW - Temporal beam shaping for precision machining
PY - 2023
UR - https://www.mdpi.com/journal/materials/special_issues/pulse_laser_machining
SN - 1996-1944
PB - MDPI
CY - Basel
AN - OPUS4-56842
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mishurova, Tatiana
T1 - 3D imaging and residual stress analysis for AM Materials
N2 - The overview of the activity of Federal Institute for Material Research and Testing (BAM, Belin, Germany) in the field of additively manufacturing material characterization will be presented. The research of our group is focused on the 3D imaging of AM materials by means of X-ray Computed Tomography at the lab and at synchrotron, and the residual stress characterization by diffraction (nondestructive technique).
T2 - Seminar at Integrated Additive Manufacturing center, Politecnico Torino
CY - Turin, Italy
DA - 14.02.2023
KW - Additive manufacturing
KW - Laser powder bed fusion
KW - Residual stress
KW - Computed tomography
KW - Synchrotron X-ray diffraction
PY - 2023
AN - OPUS4-57047
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kraft, Sebastian
A1 - Schille, J.
A1 - Bonse, Jörn
A1 - Löschner, U.
A1 - Krüger, Jörg
T1 - X‑ray emission during the ablative processing of biological materials by ultrashort laser pulses
N2 - The ablative laser processing with ultrashort pulsed laser beams may cause secondary emission of hazardous X-rays. While the effect has recently been proven to be considered in working safety regulations when processing technical materials, such as metals, the X-ray emission rates during the ablative processing of biological tissue materials are widely unexplored yet.
Therefore, biological materials like water, isotonic saline solution, pig eyes, and human teeth were ablated with ultrashort laser pulses of 1030 nm wavelength, 600 fs pulse duration and 5 kHz pulse repetition rate, aiming to mimic typical surgery situations. Simultaneously, in-situ X-ray dose rate measurements were performed at a short distance from the plasma to display potential X-ray emission. For all four studied biological materials, our measurements prove the secondary emission of laser-induced X-rays.
KW - Ultrashort pulsed laser
KW - Laser-induced X-ray emission
KW - Ophthalmology
KW - Dentistry
KW - Secondary hazard
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569960
DO - https://doi.org/10.1007/s00339-023-06440-4
SN - 0947-8396
VL - 129
IS - 3
SP - 1
EP - 8
PB - Springer
AN - OPUS4-56996
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Dengel, Jörg
T1 - Geschäftsbericht der Konformitätsbewertungsstelle Explosivstoffe / Pyrotechnik
N2 - Übersicht über aktuelle Themen, Probleme, Herausforderungen und Entscheidungen als benannte Stelle für Pyrotechnik nach 2013/29/EU und Explosivstoffe nach 2014/28/EU.
T2 - 25. Sitzung des Beirats der BAM-Zertifizierungsstelle (BZS)
CY - Berlin, Germany
DA - 14.02.2023
KW - UKCA
KW - Konformitätsbewertung
KW - Statistik
KW - Brexit
KW - Normung
KW - Audit
PY - 2023
AN - OPUS4-56997
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Würth, Christian
T1 - Time resolved spectroscopy of upconverting lanthanide based upconversion nanocrystals
N2 - The optical properties of these materials strongly depend on the excitation power density, i.e., the number of photons absorbed per time interval. The upconversion quantum efficiencies (ΦUC) of these materials, the excitation power dependent population i.e. the emission characteristics, and the deactivation dynamics are influenced by nanoparticle architecture, doping concentration, and the microenvironment. We will discuss how time resolved measurements can help to understand the fundamental photophysical mechanisms and discuss differences to other nanocrystals like quantum dots.
T2 - 19th International Course on “Principles and Applications of Time-resolved Fluorescence Spectroscopy”
CY - Berlin, Germany
DA - 16.11.2022
KW - Nanoparticle
KW - Lanthanide
KW - Upconversion
KW - Energy transfer
PY - 2022
AN - OPUS4-57000
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schneider, M.
A1 - Schlingmann, T.
A1 - Schmidt, J.
A1 - Bettge, Dirk
A1 - Hilgenberg, Kai
A1 - Binder, M.
A1 - Klöden, B.
T1 - A Round Robin Test To Investigate The Printing Quality Of PBF LB/M Processed AlSi10Mg
N2 - When it comes to higher accuracies, new technologies and real applications in additive manufacturing, there is one topic which cannot be avoided: The material response on the chosen processing parameters and its agreement and correspondence with literature data of the wrought material grade counterpart. In industrial Additive Manufacturing (AM) standards in terms of printing parameters, protection gas atmospheres or powder handling instructions are not obligatory. Therefore, the question must be answered whether the AM process is reproducible and reliable over different printing companies. This was the motivation to realize a round robin test between 8 European printing companies and academic partners. The consortium had printed and tested fatigue and tensile testing bars under plant-specific conditions. A commonly used cast aluminum alloy, AlSi10Mg, was chosen as test material for the PBF-LB/M process. Differences of the results between the partners and the scatter itself were discussed in detail.
T2 - World PM2022
CY - Lyon, France
DA - 09.10.2022
KW - Additive manufacturing
KW - AlSi10Mg
KW - Laser powder bed fusion
KW - Round robin
KW - Reproducibility
PY - 2022
AN - OPUS4-56303
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schneider, M.
A1 - Schlingmann, T.
A1 - Schmidt, J.
A1 - Bettge, Dirk
A1 - Hilgenberg, Kai
A1 - Binder, M.
A1 - Klöden, B.
T1 - A Round Robin Test To Investigate The Printing Quality Of PBF-LB/M Processed AlSi10Mg
N2 - When it comes to higher accuracies, new technologies and real applications in additive manufacturing, there is one topic which cannot be avoided: The material response on the chosen processing parameters and its agreement and correspondence with literature data of the wrought material grade counterpart. In industrial Additive Manufacturing (AM) standards in terms of printing parameters, protection gas atmospheres or powder handling instructions are not obligatory. Therefore, the question must be answered whether the AM process is reproducible and reliable over different printing companies. This was the motivation to realize a round robin test between 8 European printing companies and academic partners. The consortium had printed and tested fatigue and tensile testing bars under plant-specific conditions. A commonly used cast aluminum alloy, AlSi10Mg, was chosen as test material for the PBF-LB/M process. Differences of the results between the partners and the scatter itself were discussed in detail.
T2 - World PM2022
CY - Lyon, France
DA - 09.10.2022
KW - Additive manufacturing
KW - Round robin
KW - Reproducibility
KW - Laser powder bed fusion
KW - AlSi10Mg
PY - 2022
SN - 978-1-899072-54-5
SP - 1
EP - 10
PB - European Powder Metallurgy Association (EPMA)
AN - OPUS4-56304
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Macková, A.
A1 - Jagerová, A.
A1 - Lailik, O.
A1 - Miksová, R.
A1 - Poustka, D.
A1 - Mistrík, J.
A1 - Holý, V.
A1 - Schütter, Jan David
A1 - Kentsch, U.
A1 - Marvan, P.
A1 - Azarov, A.
A1 - Galeckas, A.
T1 - Combined Au/Ag nanoparticle creation in ZnO nanopillars by ion implantation for optical response modulation and photocatalysis
N2 - ZnO nanopillars were implanted with Au-400 keV and Ag-252 keV ions with ion fluences from 1 × 10^15 cm^2 to 1 × 10^16 cm^2. We compared ZnO nanopillars solely implanted with Au-ions and dually-implanted with Au and Ag-ions. Rutherford Back-Scattering spectrometry (RBS) confirmed Ag and Au embedded in ZnO nanopillar layers in a reasonable agreement with theoretical calculations. A decreasing thickness of the ZnO nanopillar layer was evidenced with the increasing ion implantation fluences. Spectroscopic Ellipsometry (SE) showed a decrease of refractive index in the nanopillar parts with embedded Au, Ag-ions. XRD discovered vertical domain size decreasing with the proceeding radiation damage accumulated in ZnO nanopillars which effect was preferably ascribed to Au-ions. SE and diffuse reflectance spectroscopy (DRS) showed optical activity of the created nanoparticles at wavelength range 500 – 600 nm and 430 – 700 nm for the Au-implanted and Au, Ag-implanted ZnO nanopillars, respectively. Photoluminescence (PL) features linked to ZnO deep level emission appear substantially enhanced due to plasmonic interaction with metal nanoparticles created by Ag, Au-implantation.
Photocatalytic activity seems to be more influenced by the nanoparticles presented in the layer rather than the surface morphology. Dual implantation with Ag, Au-ions enhanced optical activity to a larger extent without significant morphology deterioration as compared to the solely Au-ion implanted nanopillars.
KW - ZnO nanopillars
KW - Au/Ag nanoparticles,
KW - Ion implantation
KW - SPR
KW - Doped ZnO nanostructures
PY - 2022
DO - https://doi.org/10.1016/j.apsusc.2022.155556
SN - 0169-4332
VL - 610
SP - 1
EP - 13
PB - Elsevier B.V.
AN - OPUS4-56306
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sergievskaya, A.
A1 - Absil, R.
A1 - Chauvin, A.
A1 - Yusenko, Kirill
A1 - Vesely, J.
A1 - Godfroid, T.
A1 - Konsstantinidis, S.
T1 - Sputtering onto liquids: How does the liquid viscosity affect the formation of nanoparticles and metal films?
N2 - This paper reports on the effect of the solvent viscosity on the formation of gold nanoparticles (Au NPs) during Sputtering onto Liquid (SoL) process. All other parameters related to the plasma and the host liquid are kept constant. SoL is a simple highly reproducible approach for preparation of colloidal dispersions of small naked NPs. The properties of the final product are determined by both the sputtering parameters and the host liquid characteristics. As a model system we chose to sputter a gold target by a direct-current magnetron discharge onto a line of polymerized rapeseed oils having similar surface tension (32.6 ― 33.1 mJ·m-2 at RT). It was found that well dispersed Au NPs grow in the bulk solution of oils with low viscosities (below 630 cP at 25 °C) while gold films form onto the surface of high viscosity liquids (more than 1000 cP at 25 °C). The mean diameter of the individual Au NPs slightly increases with oil viscosity and is in range about 2.1―2.5 nm according to transmission electron microscopy.
KW - Liquid spattering
KW - Nanoparticles
PY - 2023
DO - https://doi.org/10.1039/D2CP03038A
SN - 1463-9084
VL - 25
IS - 4
SP - 2803
EP - 2809
PB - RSC Publ.
CY - Cambridge
AN - OPUS4-56562
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bachmann, Marcel
A1 - Meng, Xiangmeng
A1 - Artinov, Antoni
A1 - Rethmeier, Michael
T1 - Evaluation of narrowed weld pool shapes and their effect on resulting potential defects during deep penetration laser beam welding
N2 - This study presents mechanisms of the evolution of a narrowed region in the weld pool center during deep penetration laser beam welding. In numerous numerical studies presented in this study, it was also found that the local reduction of the weld pool size can cause detrimental effects on the melt flow behavior and the resulting properties of the welds. A particularly large influence of this effect was identified in three aspects. Firstly, the local variation of the solidification sequence of the weld pool causes an increase in the hot-cracking susceptibility due to a locally delayed solidification. Secondly, it was proven that a change in the local length and width of the weld pool is associated with an adverse impact on the potential flow routes of the molten material that induces stronger local variations of its solidification. Thus, the element mixing, e.g. during the welding with filler materials, is blocked. This leads to a non-homogeneous chemical composition of the final weld and can cause undesired effects on the final material properties. Finally, another observed effect is related to the reduced ability of process pores to reach the top surface. As this type of porosity is usually produced around the keyhole tip, the change of the fluid flow regime above this area plays a significant role in determining the final path of the pores until the premature solidification in the middle of the weld pool captures them. This study summarizes mainly numerical results which were supported by selected experimental validation results.
T2 - International Congress of Applications of Lasers & Electro-Optics 2022
CY - Orlando, FL, USA
DA - 17.10.2022
KW - Weld pool shape
KW - Laser beam welding
KW - Solidification
KW - Porosity
KW - Numerical process simulation
PY - 2022
SP - 1
AN - OPUS4-56532
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lehmann, Jens
T1 - VORSTELLUNG DES NEUEN GFKORR ARBEITSKREISES „ATMOSPHÄRISCHE KORROSION“
N2 - In diesem Vortrag wird ein Überblick über die Themen und Schwerpunkte des Arbeitskreises Atmosphärische Korrosion gegeben. Dabei werden einige Beispiele für relevante Fragestellungen aufgegriffen.
T2 - Sitzung des GfKORR AK Eisen und Stahl
CY - Online meeting
DA - 08.12.2022
KW - Korrosion
KW - Atmosphäre
KW - Luftqualität
KW - Auslagerungsversuche
PY - 2022
AN - OPUS4-56546
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 - JOUR
A1 - Böttcher, Katrin
A1 - Schmitt Rahner, M.
A1 - Stolzenberg, U.
A1 - Kraft, Sebastian
A1 - Bonse, Jörn
A1 - Feist, C.
A1 - Albrecht, D.
A1 - Pullner, B.
A1 - Krüger, Jörg
T1 - Worst-case X-ray photon energies in ultrashort pulse laser processing
N2 - Ultrashort pulse laser processing can result in the secondary generation of unwanted X-rays if a critical laser irradiance of about 10^13 W/cm^2 is exceeded. Spectral X-ray emissions were investigated during the processing of tungsten and steel using three complementary spectrometers (based on CdTe and silicon drift detectors) simultaneously for the identification of a worst-case spectral scenario. Therefore, maximum X-ray photon energies were determined, and corresponding dose equivalent rates were calculated. An ultrashort pulse laser workstation with a pulse duration of 274 fs, a center wavelength of 1030 nm, pulse repetition rates between 50 kHz and 200 kHz, and a Gaussian laser beam focused to a spot diameter of 33 µm was employed in a single pulse and burst laser operation mode. Different combinations of laser pulse energy and repetition rate were utilized, keeping the average laser power constant close to the maximum power of 20 W. Peak irradiances ranging from 7.3 × 10^13 W/cm^2 up to 3.0 × 10^14 W/cm^2 were used. The X-ray dose equivalent rate increases for lower repetition rates and higher pulse energy if a constant average power is used. Laser processing with burst mode significantly increases the dose rates and the X-ray photon energies. A maximum X-ray photon energy of about 40 keV was observed for burst mode processing of tungsten with a repetition rate of 50 kHz and a peak irradiance of 3 × 10^14 W/cm^2.
KW - Ultrashort pulsed laser
KW - X-ray emission
KW - X-ray spectrum
KW - X-ray energies
KW - Radiation protection
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-566176
DO - https://doi.org/10.3390/ma15248996
VL - 15
IS - 24
SP - 1
EP - 17
PB - MDPI
AN - OPUS4-56617
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Epperlein, Martin
T1 - Digitalisierung in der Additiven Fertigung
N2 - Die Entwicklung einer digitalen QI ermöglicht die objektive Qualitätssicherung in der Additiven Fertigung und macht die Technologie gerade auch für kleine und mittelständische Unternehmen besser nutzbar. Sie wird vollwertig im Rahmen des Qualitätsanspruchs „Made in Germany“ einsetzbar – gerade auch beim Umbruch in Industriezweigen. Der Vortrag gibt Einblicke in aktuelle Arbeiten und die Ziele des Use Case Additive Fertigung.
T2 - LEF-Themenwoche, Bayerisches Laserzentrum
CY - Online meeting
DA - 21.03.2023
KW - Digitalisierung
KW - Qualitätsinfrastruktur
KW - Additive Fertigung
KW - Qualitätssicherung
PY - 2023
AN - OPUS4-57186
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Harsha, A. P.
A1 - Wäsche, Rolf
A1 - Joyce, T. J.
T1 - Friction and wear of two polyethylenes under different tribological contact conditions
N2 - Tribological properties of ultrahigh-molecular weight polyethylene (UHMWPE) and cross-linked polyethylene (XLPE) were studied in two different wear modes. Firstly, reciprocating sliding wear studies under non-conformal contact investigated the effects of counterface surface roughness (polished, lapped and ground) of Ti6Al4V on the friction and wear of the polyethylenes. Secondly, two-body abrasive wear studies in conformal contact against different abrasive grit size papers were also carried out to ascertain the wear sensitivity of the polyethylenes under these adverse conditions. Wear mechanisms were studied using optical and scanning electron micrographs. The results of the reciprocating sliding wear studies showed that surface roughness of the counterface influenced friction and wear characteristics although no correlation was found between the coefficient of friction and specific wear rate. XLPE demonstrated wear sensitivity, particularly under severe abrasive wear condition. The results indicated that the performance of the polyethylenes greatly depends upon the tribological system under which it is operating.
KW - Abrasive wear
KW - Polyethylene
KW - Reciprocating sliding wear
KW - Surface roughness
KW - Wear mechanism
PY - 2021
DO - https://doi.org/10.1177/0967391120920130
SN - 0967-3911
SN - 1478-2391
VL - 29
IS - 5
SP - 393
EP - 404
PB - Sage Publishing
CY - London
AN - OPUS4-56903
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kinne, R. W.
A1 - Gunnella, F.
A1 - Kunisch, E.
A1 - Heinemann, S.
A1 - Nies, B.
A1 - Maenz, S.
A1 - Horbert, V.
A1 - Illerhaus, Bernhard
A1 - Huber, R.
A1 - Firkowska-Boden, I.
A1 - Bossert, J.
A1 - Jandt, K. D.
A1 - Sachse, A.
A1 - Bungartz, M.
A1 - Brinkmann, O.
T1 - Performance of calcium phosphate cements in the augmentation of sheep vertebrae - An ex vivo study
N2 - Oil-based calcium phosphate cement (Paste-CPC) shows not only prolonged shelf life and injection times, but also improved cohesion and reproducibility during application, while retaining the advantages of fast setting, mechanical strength, and biocompatibility. In addition, poly(L-lactideco-glycolide) (PLGA) fiber reinforcement may decrease the risk for local extrusion. Bone defects (diameter 5 mm; depth 15 mm) generated ex vivo in lumbar (L) spines of female Merino sheep (2–4 years) were augmented using: (i) water-based CPC with 10% PLGA fiber reinforcement (L3); (ii) Paste-CPC (L4); or (iii) clinically established polymethylmethacrylate (PMMA) bone cement (L5). Untouched (L1) and empty vertebrae (L2) served as controls. Cement performance was analyzed using micro-computed tomography, histology, and biomechanical testing. Extrusion was comparable for Paste-CPC(-PLGA) and PMMA, but significantly lower for CPC + PLGA. Compressive strength and Young’s modulus were similar for Paste-CPC and PMMA, but significantly higher compared to those for empty defects and/or CPC + PLGA. Expectedly, all experimental groups showed significantly or numerically lower compressive strength and Young’s modulus than those of untouched controls. Ready-to-use Paste-CPC demonstrates a performance similar to that of PMMA, but improved biomechanics compared to those of water-based CPC + PLGA, expanding the therapeutic arsenal for bone defects. O, significantly lower extrusion of CPC + PLGA fibers into adjacent lumbar spongiosa may help to reduce the risk of local extrusion in spinal surgery.
KW - Sheep
KW - PMMA
KW - Calcium phosphate bone cement
KW - Oil-based
KW - Ready-to-use
KW - Water-based
KW - Micro-CT
KW - Compressive strength
KW - Young’s modulus
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569072
DO - https://doi.org/10.3390/ma14143873
SN - 1996-1944
VL - 14
IS - 14
SP - 1
EP - 12
PB - MDPI
CY - Basel
AN - OPUS4-56907
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Denkler, Tilman
T1 - Status of task 8.5 - quality assurance
N2 - The presentation was given at the virtual general meeting of the Horizon 2020 project "Metabuilding Labs" to inform the partners about the status of the development of the quality management documentation of MBLabs.
T2 - Metabuilding Labs General Meeting March 8th & 9th
CY - Online meeting
DA - 8.3.2023
KW - Quality Management
KW - Metabuilding Labs
PY - 2023
AN - OPUS4-57122
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Krüger, Jörg
T1 - Einführung Ultrakurzpulslaser
N2 - Der Vortrag gibt eine Einführung zu ultrakurzen Laserpulsen, der Ultrakurzpulslaser-Materialbearbeitung und dem Schutz gegenüber unerwünschter Röntgenstrahlung bei der Ultrakurzpulslaser-Materialbearbeitung.
T2 - Vorkommnisse in der Medizin und Ultrakurzpulslaser, Veranstaltungsreihe: Erfahrungsaustausch zu Themen des Vollzugs im Strahlenschutz
CY - Cologne, Germany
DA - 26.04.2023
KW - Ultrakurze Laserpulse
KW - Materialbearbeitung
KW - Röntgenstrahlung
KW - Strahlenschutz
KW - Abschirmung
PY - 2023
AN - OPUS4-57408
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stolar, Tomislav
A1 - Pearce, Ben K.D.
A1 - Etter, Martin
A1 - Truong, Khai-Nghi
A1 - Ostojić, Tea
A1 - Krajnc, Andraž
A1 - Mali, Gregor
A1 - Rossi, Barbara
A1 - Molčanov, Krešimir
A1 - Lončarić, Ivor
A1 - Meštrović, Ernest
A1 - Užarević, Krunoslav
A1 - Grisanti, Luca
T1 - Base-pairing of uracil and 2,6-diaminopurine: from cocrystals to photoreactivity
N2 - We show that the non-canonical nucleobase 2,6-diaminopurine (D) spontaneously base pairs with uracil (U) in water and the solid state without the need to be attached to the ribose-phosphate backbone. Depending on the reaction conditions, D and U assemble in thermodynamically stable hydrated and anhydrated D-U base-paired cocrystals. Under UV irradiation, an aqueous solution of D-U base-pair undergoes photochemical degradation, while a pure aqueous solution of U does not. Our simulations suggest that D may trigger the U photodimerization and show that complementary base-pairing modifies the photochemical properties of nucleobases, which might have implications for prebiotic chemistry.
KW - Mechanochemistry
KW - In situ monitoring
KW - Cocrystals
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-608622
DO - https://doi.org/10.1016/j.isci.2024.109894
VL - 27
IS - 6
SP - 1
EP - 14
PB - Elsevier Inc.
AN - OPUS4-60862
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Davison, Nathan
A1 - Hemingway, Jack M.
A1 - Wills, Corinne
A1 - Stolar, Tomislav
A1 - Waddell, Paul G.
A1 - Dixon, Casey M.
A1 - Barron, Luke
A1 - Dawson, James A.
A1 - Lu, Erli
T1 - Mechanochemical Synthesis of a Sodium Anion Complex [Na+(2,2,2-cryptand)Na–] and Studies of Its Reactivity: Two-Electron and One-Electron Reductions
N2 - Group 1 metal molecular chemistry is dominated by a +1 oxidation state, while a 0 oxidation state is widespread in the metals. A more exotic, yet still available, oxidation state of group 1 metal is −1, i.e., alkalide. Reported as early as the 1970s, the alkalides appear in every modern inorganic chemistry textbook as an iconic chemical curiosity, yet their reactivity remains unexplored. This is due to their synthetic hurdles. In this work, we report the first facile synthesis of the archetypical alkalide complex, [Na+(2,2,2-cryptand)Na–], which allows us to unveil a versatile reactivity profile of this once exotic species.
KW - Mechanochemistry
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-608632
DO - https://doi.org/10.1021/acs.inorgchem.4c02914
VL - 63
IS - 32
SP - 15247
EP - 15258
PB - American Chemical Society (ACS)
AN - OPUS4-60863
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Giv, Ali Nemati
A1 - Asante, Bright
A1 - Yan, Libo
A1 - Kasal, Bohumil
T1 - Shear performance and durability of adhesively bonded spruce wood-concrete composite joints: Effects of indoor and outdoor environmental conditions, mechanical load, and their coupled effect
N2 - A long-term study was conducted on double-lap spruce wood-concrete joints to investigate their shear strength and stiffness over a 12-month period. These joints were manufactured using both wet and dry processes, each incorporating two adhesive types for bonding the wood to the concrete: a brittle epoxy and a ductile polyurethane (PUR). The experimental design exposed the joints to three specific long-term environments: (1) outdoor exposure, (2) indoor conditions with applied load, and (3) outdoor conditions with applied load. The wood concrete joints exposed to outdoor conditions were subjected to destructive shear testing at intervals of 0 (serving as the reference sample), 2, 4, 6, and 12 months, respectively. For joints subjected to both indoor and outdoor conditions with shear loading, the shear deformation of joints was monitored continuously over the 12 months before performing the destructive tests. A gradual reduction in the shear stiffness and strength of dry joints (produced using the dry bond method) exposed to outdoor conditions was observed over a 12-month period, primarily due to bond failure at the concrete-adhesive interface. The wet joints exhibited no degradation in shear stiffness and strength across long-term conditions over the same period. The bond failure observed in dry joints was predominantly associated with stresses arising from dimensional changes in the wood. No degradation was found in the cross-linking density of the adhesive or in the concrete’s compressive stiffness and strength.
KW - Adhesively bonded joints
KW - Long-term study
KW - Ductile PUR
KW - Brittle epoxy
KW - Outdoor condition
KW - Mechanical load
KW - Indoor condition
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-608878
DO - https://doi.org/10.1016/j.conbuildmat.2024.136905
VL - 436
SP - 1
EP - 22
PB - Elsevier BV
AN - OPUS4-60887
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lemiasheuski, Anton
A1 - Kranzmann, Axel
A1 - Pfennig, Anja
T1 - Herausforderungen und Möglichkeiten des manuellen metallografischen Serienschnittverfahrens anhand einer quantitativen Gefügeanalyse der Grafite eines Gusseisens
T1 - Challenges and possibilities of the manual metallographic serial sectioning process using the example of a quantitative microstructural analysis of graphite in cast iron
N2 - Die in dieser Studie vorgestellte 3D-Gefüge-Analyse konzentriert sich auf die Kugelgrafite eines Gusseisens des Typs EN-GJS. Es werden die Form anhand des Formfaktors und des Seitenverhältnisses sowie die durchschnittliche Teilchengröße und -verteilung untersucht.
Die Form der Grafite in Gusseisenwerkstoffen ist mitentscheidend für die mechanischen Eigenschaften dieser Legierungen und ist bei der Charakterisierung des Werkstoffs unumgänglich. Mittels Metallografischen Serienschnittverfahrens wird von dem Schicht für Schicht abgetragenen und lichtmikroskopisch schichtweise dargestellten Werkstoff ein digitaler Zwilling erstellt. Von diesem dreidimensionalen Zwilling lassen sich beliebige Ebenen digital projizieren und analysieren. Eine konventionelle quantitative 3D-Analyse untersucht die Voxelmenge und -zusammensetzung eines Körpers im 3D-Raum. Die hier vorgestellte Analyse wendet stereologische 2D-Analyseverfahren auf drei Raumebenen des Werkstoffs an. Dabei sind zwei der Ebenen digitale Projektionen des Zwillings. Die zwei rekonstruierten Ebenen des Werkstoffs sind so gewählt, dass die Richtungsvektoren aller drei Ebenen einen 90°-Winkel zueinander bilden. Diese Methodik wird eingehend beschrieben sowie Herausforderungen und Möglichkeiten des hier vorgestellten Serienschnittverfahrens diskutiert.
N2 - The 3D microstructure analysis presented in this study focuses on the nodular graphite of an EN-GJS grade cast iron. The shape is analyzed based on shape factor and aspect ratio as well as average particle size and distribution. The shape of graphites in cast iron materials is critical to the mechanical properties of these alloys and is essential for the characterization of the material. Metallographic serial sectioning creates a digital twin of the material, which is removed layer by layer and visualized layer by layer under an optical microscope. From this three-dimensional twin, any number of planes can be digitally projected and analyzed. Conventional quantitative 3D analysis examines the voxel count and composition of a body in 3D space. The analysis presented here applies stereological 2D analysis methods to three spatial planes of the material. Two of the planes are digital projections of the twin. The two reconstructed planes of the material are chosen so that the direction vectors of all three planes form an angle of 90° to each other. The methodology is described in detail and the challenges and opportunities of the serial section method presented here are discussed.
KW - Dreidimensionale Gefügeanalyse
KW - Three-dimensional microstructure analysis
KW - 3D-Metallografie
KW - Serienschnittverfahren
KW - Gefügerekonstruktion
KW - Quantitative Gefügeanalyse
KW - 3D metallography
KW - Serial sectioning
KW - Microstructure reconstruction
KW - Quantitative microstructure analysis
PY - 2024
DO - https://doi.org/10.1515/pm-2024-0066
SN - 0032-678X
VL - 61
IS - 9-10
SP - 746
EP - 768
PB - De Gruyter
CY - Berlin/Boston
AN - OPUS4-60976
LA - mul
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ermilova, Elena
A1 - Hertwig, Andreas
A1 - Döhring, Thorsten
A1 - Stanik, Eva
A1 - Cotroneo, Vincenzo
A1 - Gibertini, Eugenio
T1 - Ellipsometrical characterization of poly-dopamine layers considered for technical applications
N2 - Although the organic molecule dopamine (3,4-dihydroxyphenethylamine) is commonly known as the “hormone of happiness”, thin films of poly-dopamine also have interesting technical properties. When produced by dip coating, the self-organizing layers grow in a reproducible thickness of single or multiple molecule monolayers of a few nanometer thickness only. In this work, we introduce a method of determining the layer thickness of poly-dopamine on mirrors for astronomical X-ray telescopes. This work is based on spectroscopic ellipsometry measurements and involves the development of an optical model for the poly-dopamine layers including the dielectric function. Thereby the complex refractive index of the produced layers was determined, covering the range from the ultraviolet to the near infrared spectral region. These measurement results and the corresponding technical challenges are presented in this contribution. Furthermore, an outlook to potential technical applications of this interesting material is given and poly-dopamine layers will make scientist and engineers hopefully happy as an innovative and fascinating technical solution for the future.
T2 - SPIE PHOTONICS EUROPE
CY - Strasbourg. France
DA - 08.04.2024
KW - Polydopamine
KW - Thin Solid Layers
KW - X-ray optics
KW - Spectroscopic Ellipsometry
PY - 2024
SN - 978-1-5106-7344-1
DO - https://doi.org/10.1117/12.3015281
VL - 13013
SP - 1
EP - 8
PB - SPIE digital library
AN - OPUS4-60954
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Omar, Hassan
A1 - Hertwig, Andreas
A1 - Szymoniak, Paulina
A1 - Schönhals, Andreas
T1 - Signature of the Adsorbed Layer on the glass transition of thin polymer Films: Broadband Dielectric spectroscopy and related techniques
N2 - In well annealed thin polymer films with non-repulsive polymer/substrate interaction with a substrate an irreversibly adsorbed layer is expected to form. These adsorbed layers have shown a great potential for technological applications [1]. However, the growth kinetics and the molecular mobility of the adsorbed layer is still not fully understood. This concerns also the influence of the adsorbed layer on the thickness dependence of the glass transition temperature of thin films. This is partly due to the difficult accessibility of these layers in thin films. Here, the irreversibly adsorbed layers of semi-rigid mail chain polymers like polycarbonate or polysulfone are revealed by solvent-leaching experiments. First, the growth kinetics of these layers is investigated as a function of annealing time. The film thickness, topography and the quality of the adsorbed layer is controlled by Atomic Force Microscopy (AFM). Secondly, the molecular mobility of the adsorbed layer is investigated by Broadband Dielectric Spectroscopy (BDS). A developed nanostructured capacitor arrangement is employed to measure the layer with a free surface. In addition to the dielectric experiments, spectroscopic Ellipsometry measurements are carried out to estimate the glass transition of the thin films. The thickness dependence of the glass transition of the thin films is correlated with the adsorbed layer [2,3].
Acknowledgments
D. Hülagü and G. Hidde thanked for the help with the ellipsometry measurements.
T2 - 12. Conference on Broabband Dielectric Spectroscopy and its Application
CY - Lisbon, Portugal
DA - 01.09.2024
KW - Thin films
PY - 2024
AN - OPUS4-60959
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wegner, Karl David
A1 - Hildebrandt, N.
T1 - Near infrared quantum dots for biosensing and bioimaging
N2 - Quantum dots (QDs) possess unique optoelectronic properties, which make them very attractive to be used as optical probes in biosensing and bioimaging applications. The strong absorbance and light scattering of biological compounds like tissue and blood in the visible range pose a problem. However, if optical probes emitting in the near-infrared (NIR) range are used, scattering, absorption, and autofluorescence of biological components are strongly reduced. This allows for an increased light penetration depth and higher spatial and temporal resolution for the investigation of biological processes. The synthesis and application of NIR emitting QDs is a fast-growing research field and the benefits of using QDs were demonstrated for a variety of applications, such as photoelectrochemical biosensor, in vivo vascular imaging, and fluorescence-guided surgery. This article reviews the state-of-the-art developments in the preparation of NIR/IR QDs and highlights the latest research about their utilization in biosensing and bioimaging applications.
KW - Quantum dots
KW - Near-infrared
KW - Biosensing
KW - Bioimaging
KW - NIR-II / SWIR
KW - Advanced nanomaterials
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-609708
SN - 0165-9936
DO - https://doi.org/10.1016/j.trac.2024.117922
VL - 180
SP - 1
EP - 19
PB - Elsevier B.V.
AN - OPUS4-60970
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Diller, Johannes
A1 - Siebert, Ludwig
A1 - Winkler, Michael
A1 - Siebert, Dorina
A1 - Blankenhagen, Jakob
A1 - Wenzler, David
A1 - Radlbeck, Christina
A1 - Mensinger, Martin
T1 - An integrated approach for detecting and classifying pores and surface topology for fatigue assessment 316L manufactured by powder bed fusion of metals using a laser beam using μ$$ \mu $$CT and machine learning algorithms
N2 - AbstractThis research aims to detect and analyze critical internal and surface defects in metal components manufactured by powder bed fusion of metals using a laser beam (PBF‐LB/M). The aim is to assess their impact on the fatigue behavior. Therefore, a combination of methods, including image processing of micro‐computed tomography (CT) scans, fatigue testing, and machine learning, was applied. A workflow was established to contribute to the nondestructive assessment of component quality and mechanical properties. Additionally, this study illustrates the application of machine learning to address a classification problem, specifically the categorization of pores into gas pores and lack of fusion pores. Although it was shown that internal defects exhibited a reduced impact on fatigue behavior compared with surface defects, it was noted that surface defects exert a higher influence on fatigue behavior. A machine learning algorithm was developed to predict the fatigue life using surface defect features as input parameters.
KW - Fatigue
KW - Machine learning
KW - Micro-computed tomography
KW - Powder bed fusion of metals using a laser beam
KW - Quality assurance
PY - 2024
DO - https://doi.org/10.1111/ffe.14375
SN - 8756-758X
SP - 1
EP - 16
PB - John Wiley & Sons Ltd.
AN - OPUS4-60593
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lengas, Nikolaos
T1 - Drop test simulation of packaging for dangerous goods: Investigation of appropriate drop height adjustment
N2 - In the approval process of dangerous goods packagings, drop tests onto a flat, essentially unyielding surface are used to assess resistance against mechanical damage. International adopted regulations like ADR and RID define filling good dependent drop heights and filling degrees whilst the user needs to define the maximum gross mass to be tested and approved. Maximum packaging gross mass is defined conservatively and not reached in practice. To meet the defined gross mass in testing, using additives is permitted. However, in some cases, additives are not desirable due to packaging design or filling substance properties. This leads to deviations from the initial gross mass definition. Hence, a certain drop height adjustment is necessary to achieve the required impact loading. Laboratories frequently adjust drop height assuming a perfectly elastic collision which is inaccurate. Appropriate adjustment is not trivial due to energy conversion processes, e.g., plastic deformation. In this work, a test stand is developed for measuring the change in kinetic energy of different packaging designs and filling substances in regulative drop tests. The experimental results are used to validate finite-element (FE) models so that packaging properties can be varied in simulated drop test scenarios. The findings intend to describe the appropriate drop height adjustment of the respective packaging with same design but deviating gross mass to produce comparable mechanical response. The results are highly beneficial for testing laboratories, approval issuing authorities and packaging institutes confronted with the problem of testing packages with gross masses other than those to be approved.
T2 - 24th IAPRI World Conference
CY - Valencia, Spain
DA - 17.06.2024
KW - Dangerous goods packagings
KW - FEM
KW - Drop test
KW - Mechanical response
PY - 2024
AN - OPUS4-60607
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Krankenhagen, Rainer
T1 - Thermographic Investigation of the Anisotropic Behaviour of Additively Manufactured AISI 316 Steel using DED-arc
N2 - Additive manufacturing is one of the most promising techniques for industrial production and maintenance, but the specifics of the layered structure must be considered. The Direct Energy Deposition-Arc process enables relatively high deposition rates, which is favourable for larger components. For this study, specimens with different orientations were prepared from one AISI316 steel block – parallel and orthogonal to the deposition plane. Quasistatic tensile loading tests were carried out, monitored by an infrared camera. The obtained surface temperature maps revealed structural differences between both orientations. The consideration of surface temperature transients yields more details about the behaviour of the material under tensile loading than the conventional stress-strain-curve. These preliminary investigations were supplemented by thermographic fatigue trials. Although the anisotropy was also observed during fatigue loading the fatigue behaviour in general was the same, at least for both inspected specimens. The presented results demonstrate the abilities and the potential of thermographic techniques for tensile tests.
T2 - 17th Quantitative Infrared Thermography Conference
CY - Zagreb, Croatia
DA - 01.07.2024
KW - Thermoelastic effect
KW - Thermoplastic effect
KW - Thermal stress analysis
PY - 2024
AN - OPUS4-60574
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bacurau, V. P.
A1 - Moreira, P. A. F. P.
A1 - Bertoli, G.
A1 - Andreoli, A. F.
A1 - Mazzer, E.
A1 - de Assis, F. F.
A1 - Gargarella, P.
A1 - Koga, G.
A1 - Stumpf, G. C.
A1 - Figueroa, S. J. A.
A1 - Widom, M.
A1 - Kaufman, M.
A1 - Fantin, Andrea
A1 - Cao, Y.
A1 - Freitas, R.
A1 - Miracle, D.
A1 - Coury, F. G.
T1 - Comprehensive analysis of ordering in CoCrNi and CrNi2 alloys
N2 - Chemical Short-Range Order (CSRO) has attracted recent attention from many researchers, creating intense debates about its impact on material properties.
The challenges lie in confirming and quantifying CSRO, as its detection proves exceptionally demanding, contributing to conflicting data in the literature regarding its true effects on mechanical properties. Our work uses highprecision calorimetric data to unambiguously prove the existence and, coupled with atomistic simulations, quantify the type of CSRO. This methodology allows us to propose a mechanism for its formation and destruction based on the heat evolution during thermal analysis and facilitates a precise identification of local ordering in CoCrNi alloys. Samples of CoCrNi (Co33Cr33Ni33) and CrNi2 (Cr33Ni66) alloys are fabricated in varying ordered states, extensively characterized via synchrotron X-ray diffraction, X-ray absorption spectroscopy, and transmission electron microscopy. Samples with considerably different ordered states are submitted to tensile tests with in-situ synchrotron X-ray diffraction. We demonstrate, despite inducing varied CSRO levels in CoCrNi, no significant alterations in overall mechanical behavior emerge.
However, the CrNi2 alloy, which undergoes long-range ordering, experiences significant shifts in yield strength, ultimate tensile stress and ductility.
KW - Mechanical properties
KW - Short-range ordering
KW - Calorimetry
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-611075
DO - https://doi.org/10.1038/s41467-024-52018-w
VL - 15
IS - 1
SP - 1
EP - 11
PB - Springer Science and Business Media LLC
AN - OPUS4-61107
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Alić, Jasna
A1 - Schlegel, Moritz-Caspar
A1 - Emmerling, Franziska
A1 - Stolar, Tomislav
T1 - Meeting the UN Sustainable Development Goals with Mechanochemistry
N2 - Chemistry traditionally relies on reactions in solution, but this method is increasingly problematic due to the scale of chemical processes and their economic and environmental impact. Handling residual chemical waste, including solvents, incurs significant costs and environmental pressure. Conversely, novel chemical approaches are needed to address pressing societal issues such as climate change, energy scarcity, food insecurity, and waste pollution. Mechanochemistry, a sustainable chemistry discipline that uses mechanical action to induce chemical reactivity without bulk solvents, is a hot topic in academic research on sustainable and green chemistry. Given its fundamentally different working principles from solution chemistry, mechanochemistry offers more efficient chemical processes and the opportunity to design new chemical reactions. Mechanochemistry has a profound impact on many urgent issues facing our society and it is now necessary to use mechanochemistry to address them. This Minireview aims to provide a guide for using mechanochemistry to meet the United Nations (UN) Sustainable Development Goals (SDGs), thereby contributing to a prosperous society. Detailed analysis shows that mechanochemistry connects with most UN SDGs and offers more cost‐efficiency than other approaches together with a superior environmental performance.
KW - Mechanochemistry
KW - SDGs
PY - 2024
DO - https://doi.org/10.1002/anie.202414745
SP - 1
EP - 3
PB - Wiley
AN - OPUS4-61108
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Epperlein, Martin
T1 - Digitale Qualitätssicherung in der Additiven Fertigung und Voraussetzungen in der Qualitätsinfrastruktur
N2 - Der Vortrag gibt einen Überblick über die Aktivitäten im QI-Digital Use Case Additive Fertigung, den aktuellen Stand und nächste Schritte.
Es wurde eine digitale Prozesskette für den PBF-LB/M Prozess aufgebaut. Hier werden Daten entlang der gesamten Fertigungsstrecke gesammelt, ausgewertet und zur Qualitätssicherung weiterverarbeitet. Die grundlegende Datenstruktur wurde in die Normung überführt.
T2 - TÜV SÜD Fachtagung: Additive Fertigung von Druckgeräten
CY - Munich, Germany
DA - 17.09.2024
KW - Digitalisierung
KW - Qualitätsinfrastruktur
KW - Additive Fertigung
PY - 2024
AN - OPUS4-61089
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hicke, Konstantin
T1 - Fibre Optic Sensing @BAM
N2 - The profile of division 8.6 Fibre Optic Sensors is shown, underlining specific competencies and know-how. Furthermore, several current application examples of the use of distributed fiber optic sensing for condition and state monitoring are presented.
T2 - Visit and technical tour of OECD/NEA CODAP working group led by Gesellschaft für Anlagen- und Reaktorsicherheit
CY - Berlin, Germany
DA - 19.09.2024
KW - Distributed fiber optic sensing
KW - Condition monitoring
KW - Geomonitoring
KW - Structural health monitoring
KW - Embedded fiber optic sensor
PY - 2024
AN - OPUS4-61080
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Tang, Chi-Long
T1 - UFP-Emission beim 3D-Druck
N2 - Desktop-3D-Drucker haben in der letzten Dekade große Popularität in Bildungseinrichtungen, kleinen Unternehmen und Privathaushalten erlangt. Weit verbreitet ist mittlerweile die „Fused Filament Fabrication (FFF)“ Technologie. Hier wird ein thermoplastisches Filament geschmolzen, durch eine Metalldüse extrudiert und anschließend schichtweise so auf ein Druckbett aufgetragen, dass ein 3D-Objekt entsteht. Das Filamentmaterial wird dabei thermisch stark belastet, was zur Emission von Aerosolen sowie flüchtigen organischen Verbindungen (VOC) führt. Dabei werden hauptsächlich ultrafeine Partikel (UFP, dP < 100 nm) freigesetzt werden, die sogar in manchen Fällen im sub-4nm Größenbereich einen signifikanten Anteil ausmachen können (Tang und Seeger 2024).
Die gesundheitliche Relevanz eingeatmeter UFP ist durch sehr viele Studien gut belegt. Während eines i.d.R. mehrstündigen FFF-Druckvorgangs wird ein Anwender mit diesen Luftschadstoffen im Innenraum exponiert, häufig ohne eine Einschätzung des damit verbundenen Risikos zu haben. Die Exposition kann durch technische Faktoren (z.B. Druckerausstattung und -einstellung, Innenraumventilation), aber auch erheblich durch die Filamentauswahl beeinflusst werden. Unser Vorschlag zur Risikominderung besteht in der Auszeichnung emissionsarmer Filamentprodukte mit dem Umweltzeichen „Blauer Engel“, um so den Verbrauchern eine fundierte Auswahl zu ermöglichen. In unserem Projekt entwickeln wir dafür ein kammerbasiertes, standardisierbares und robustes Prüfverfahren zur vergleichenden Messung der Emission aus Filamenten. Mit dem Strangdruck-Verfahren (engl. Strand Printing Method, SPM) wird eine festgelegte Filamentlänge mit konstanter Rate extrudiert und auf dem Druckbett abgelegt, ohne dabei ein 3D-Objekt aufzubauen. Diese Vorgehensweise reduziert den Einfluss experimentell schlecht zu kontrollierender Faktoren sowie die Ausfallquote. Eine detaillierte Beschreibung und die Vorteile von SPM werden in Tang und Seeger (2022) erläutert. SPM wurde bereits für 44 Filamentprodukte aus unterschiedlichen Polymeren und Additiven als Vergleichstest angewendet. Alle Messungen wurden in einer klimatisierten 1 m³-Emissionsprüfkammer durchgeführt. Die Gesamtanzahl der emittierten Partikel (TP) dient als Beurteilungsmaß, in Anlehnung an die Vergabegrundlage DE-UZ-219 des Umweltzeichens Blauer Engel für Laserdrucker. Unter den getesteten Filamentprodukten variiert TP um ca. vier Größenordnungen (1E+9 ≤ TP ≤ 1E+13). Auch innerhalb jeder der untersuchten Polymergruppen variierte TP signifikant. Die Partikelemission kann daher nicht allein nach dem Basispolymer kategorisiert werden. Unsere Resultate belegen, dass die Stärke der Partikelemission eher eine charakteristische und individuelle Eigenschaft eines Filamentproduktes ist. Die Herkunft der Polymere, die herstellerspezifischen Additive sowie die nicht deklarierte Verunreinigungen können einen starken Einfluss auf die Emission haben. Die Auszeichnung von emissionsarmen Filament-produkten verspricht somit eine einfache, aber effektive Maßnahme zu sein, um Verbrauchern eine Minderung des Expositionsrisikos beim FFF-3D-Druck zu ermöglichen.
T2 - 5. Symposium "Ultrafeinstaub in der Atmosphäre und in Innenräumen"
CY - Berlin, Germany
DA - 16.09.2024
KW - 3D-Druck
KW - Ultrafeine Partikel
KW - Innenraumemission
KW - Luftschadstoffe
KW - Emissionsprüfung
PY - 2024
AN - OPUS4-61067
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Merízio, Leonnam Gotardo
A1 - Machado, Ian Pompermayer
A1 - Vastamäki, Roosa
A1 - de Camargo, Andréa Simone Stucchi
A1 - Lastusaari, Mika
T1 - Multifunctional persistent luminescent and photochromic hackmanite-based materials prepared by microwave-assisted solid-state synthesis
N2 - Advanced optical materials inspired by natural minerals and non-toxic light elements, such as the Hackmanites (Na8Al6Si6O24(Cl,S)2), find vast possibilities of applications as they can simultaneously perform photochromism and persistent luminescence (PersL). In this work, we have explored a rapid and energy-efficient microwaveassisted (MASS) methodology for the synthesis of PersL and photochromic hackmanites. In addition, we have prepared hackmanite materials using a zeolite-free precursor to control the Na–Al–Si ratio and study its influence on the materials photoluminescent properties. The PersL hackmanites showed a white-bluish emission color, with up to 2 h of emission time. Zeolite-free photochromic materials were able to change the color from white to purple/blue efficiently with a few seconds of 254 nm excitation, but the usage of zeolite precursors enhanced the overall optical performance. Microwave synthesis times of 10–40 min were demonstrated to be optimal, as longer times boosted the formation of nepheline spurious phase, which decreases luminescence efficiency. In this way, the MASS method led to a reduction of reaction time up to 98 %, yielding hackmanite materials with similar photoluminescent or photochromic properties compared to those obtained by a 24 h conventional solid-state synthesis. This work represents a significant improvement toward coupling eco-friendly synthetic processes to
eco-friendly solid-state materials for PersL illumination and PersL/photochromism optical marking.
KW - Hackmanite
KW - Persistent luminescence
KW - Photochromism
KW - Microwave-assisted synthesis
PY - 2024
DO - https://doi.org/10.1016/j.optmat.2024.115826
SN - 0925-3467
VL - 155
SP - 1
EP - 13
PB - Elsevier B.V.
AN - OPUS4-60787
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Maaß, Robert
T1 - Transitions from scale-free to scale-dependent fluctuations in plasticity
N2 - Plastic deformation in crystals is mediated by the motion of line defects known as dislocations. For decades, dislocation activity has been treated as a homogeneous, smooth continuous process that relies on well-average quantities. However, it is now recognized that plasticity can be determined by long-range correlated and intermittent collective dislocation activity, known as avalanches. These abrupt plastic fluctuations often exhibit pure power-law scaling or truncated power-law scaling, which indicates at least some degree of scale-free dislocation behavior. Intriguingly, such statistical signatures can persist across scales exceeding those of the material’s microstructure, raising the question of what relationship there may be between structure and long-range correlated dislocation activity that underlie power-law scaling.
In this talk, we address this question by highlighting examples in which a transition from scale-free to scale-dependent plastic deformation is observed either due to changing external testing conditions (stress-state or temperature) or by tuning the microstructure. In particular, we will focus on the details of the temperature-driven change, that demonstrates how scale-free intermittent flow in body-centered cubic Nb is progressively quenched out with decreasing temperature. The plastic response of Nb is shown to be bimodal across the studied temperature regime, with conventional thermally-activated smooth plastic flow coexisting with sporadic bursts controlled by athermal screw dislocation activity, thereby violating the classical notion of temperature-dependent screw dislocation motion at low temperatures. An abrupt increase of the athermal avalanche component is identified at the critical temperature of the material. We combine the experimental observations with 3D dislocation dynamics simulations, identify a possible origin to athermal screw activity, and discuss the co-existence scale-free and scale-dependent plasticity.
T2 - Cairo Symposium on The Physics of Metal Plasticity
CY - Cairo, Egypt
DA - 05.09.2023
KW - Plastic deformation
KW - Dislocations
KW - Avalanches
PY - 2023
AN - OPUS4-60648
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kolmangadi, Mohamed A.
A1 - Wani, Y. M.
A1 - Schönhals, Andreas
A1 - Nikoubashman, A.
T1 - Coarse-Grained Simulations of Columnar Ionic Liquid Crystals: Comparison with Experiments
N2 - We simulate a homologous series of guanidinium-based columnar ionic liquid crystals (ILCs) using coarse-grained molecular dynamics (MD) simulations with the Martini force field. We systematically vary the length of alkyl side chains, ILC-n (n = 8, 12, 16), and compare our results with previous experimental findings. Experimentally, ILC-8 exhibits a narrow mesophase window and weak columnar order, while ILC-12 and ILC-16 display a broad mesophase window and high columnar order. The MD simulations show that ILC-8 forms a percolated structure, whereas the longer chain analogues self-assemble into columns, with columnar assembly becoming more prominent as the side chain length increases, in qualitative agreement with the experiments. Furthermore, the intercolumnar distance increases monotonically with increasing side chain length and decreases with increasing temperature. Finally, we find that the diffusion coefficient and ionic conductivity decrease substantially with increasing chain length, consistent with experimental observations. We attribute this decrease in mobility to the formation of hexagonally ordered columns, which restrict transport more than percolated networks.
KW - Ionic liquid crystals
PY - 2024
DO - https://doi.org/10.1021/acs.jpcb.4c03041
SN - 1520-6106
SP - 1
EP - 8
PB - ACS
AN - OPUS4-60857
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Glauer, M.
A1 - Schilling, Markus
A1 - Stappel, M.
T1 - A practical ontology development guide
N2 - Knowledge representation is becoming increasingly important in view of the large amounts of data that are handled in the modern scientific landscape. Many of the domains that have most readily realised this problem and worked on potential solutions have been the domain of biochemistry. And although the developments sought here were not accompanied by philosophers, this process organically led to the development of formal and structured representations of certain domains. While the resulting structures were not the first formal ontologies, they are ones that are still in wide use to this day. These approaches have led to major advances in the organisation, structuring and communication of scientific results. Since then, a variety of other domains have tried to adapt a similar process and develop their own ontologies. However, the development of ontologies from the domain of biochemistry was the result of a years-long process that also involved a large number of errors and course corrections. One of the greatest challenges is also one of the greatest strengths of ontologies: Interoperability with other ontologies. To ensure this interoperability, ontologies must follow certain principles. In the field of biochemistry, the OBO Foundry has established itself, which offers functionalities for a rich network of ontologies from the domain, but at the same time also defines rules.
The purpose of this document is to define a similar set of rules for open ontology development, but which addresses a broader domain and at the same time lowers the barrier of entry for new ontology developers. To this end, we will outline a workflow that can be used to build new ontologies more efficiently. This workflow is based not only on our own years of experience in ontology development, but also on the rules of external experts such as the OBO Foundry.
KW - Ontology
KW - Data integration
KW - Ontologie
KW - Data interoperability
PY - 2024
UR - https://scientific-ontology-network.github.io/
UR - https://github.com/scientific-ontology-network/ontology-development-guide/releases/download/v0.1.0/ontology-guide.pdf
SP - 1
EP - 27
PB - GitHub
CY - San Francisco
ET - Version 0.1
AN - OPUS4-61140
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Birkholz, Henk
A1 - Bayerlein, Bernd
T1 - Evolution of the PMD Core Ontology (PMDco) Towards ISO/IEC 21838-2:2021 Basic Formal Ontology (BFO)
N2 - Knowledge representation in the materials science and engineering (MSE) domain is a vast and multi-faceted challenge: Overlap, ambiguity, and inconsistency in terminology are common. Invariant and variant knowledge are difficult to align cross-domain. Generic top-level semantic terminology often is too abstract, while MSE domain terminology often is too specific.
In this presentation, an approach how to maintain a comprehensive and intuitive MSE-centric terminology composing a mid-level ontology–the PMD Core Ontology (PMDco)–via MSE community-based curation procedures is shown.
The PMDco is designed in direct support of the FAIR principles to address immediate needs of the global experts community and their requirements. The illustrated findings show how the PMDco bridges semantic gaps between high-level, MSE-specific, and other science domain semantics, how the PMDco lowers development and integration thresholds, and how to fuel it from real-world data sources ranging from manually conducted experiments and simulations as well as continuously automated industrial applications.
T2 - MSE Congress 2024 - Materials Science and Engineering
CY - Darmstadt, Germany
DA - 24.09.2024
KW - Ontology
KW - Semantic Interoperability
KW - Knowledge representation
KW - FAIR Data Management
KW - PMD Core Ontology
PY - 2024
AN - OPUS4-61141
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Eisenbart, Miriam
T1 - Digitalization of a high-throughput alloy development process
N2 - Digitalization is nowadays the central key in developing pharmaceutical products, but it also becomes increasingly important in computer aided material development. In this work it is presented how a collaborative ontology development for the alloy development process is approached and a workflow for chemical optimization of copper alloys is introduced. This is done by employing a combination of a high-throughput alloy development method [1] with the calculation of the corresponding phase compositions.
The work presented here is part of the publicly funded project KupferDigital. The project is associated with the innovation platform MaterialDigital (PMD) and focusses on the digitalization of processes as well as knowledge representation along the life-cycle of copper and copper alloys. One part of this life cycle is the alloy development of copper alloys, in this case the alloy development employing a high throughput method based on diffusion couples. The alloy development process can be further broken down into several typical material processing steps such as casting, diffusion welding and annealing. As part of the copper life cycle, the constitution and the properties of an alloy play an important role for processes further down the road during product manufacturing and service life and are also crucial for the recycling properties of the alloy. It is therefore important to, on the one hand, communicate data concerning properties, process history and constitution to the following stations of the life cycle, on the other hand, it is also elementary for the material scientist to be aware of the recycling properties of the alloys constituents. This motivates sharing of data along the life cycle and the development of ontology based data spaces, where life-cycle information can be linked across all involved domains.
As part of the alloy development process, it is presented how experimental data created at fem are shared using linked data and ontologies with an example based on the digital representation of the chemical composition of copper alloys further processed by CALculation of PHAse Diagrams (CALPHAD) at the Fraunhofer IWM. The calculation results are used to correlate measured hardness data with the equilibrium phases of the alloys. Selected Compositions are cast and heat treated and subjected to mechanical testing at BAM and the resulting mechanical property-data are again linked to the measured and simulated data from the alloy development process.
T2 - MSE2024
CY - Darmstadt, Germany
DA - 24.09.2024
KW - Digitalization
KW - Alloy development
PY - 2024
AN - OPUS4-61150
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hilgenberg, Kai
T1 - Additive Fertigungsverfahren und Defekte
N2 - Überblick über die derzeitig wichtigsten additiven Fertigungsverfahren für metallische Werkstoffe in der Industrie (PBF, DED, BJT) und Berücksichtigung der wesentlichen Prozessmerkmale und Nachbearbeitungsschritte. Vorstellung der wichtigsten Defektphänomene und Nennung von Ursachen und Abhilfemaßnahmen.
T2 - BAM Akademie: Qualitätssicherung in der additiven Fertigung
CY - Online meeting
DA - 17.09.2024
KW - Additive Fertigung
KW - Defekte
KW - Überblick
PY - 2024
AN - OPUS4-61172
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schob, Daniela
T1 - Deformation-Induced Martensitic Transformation in Fused Filament Fabricated Austenitic Stainless Steels During Tension at Wide Range of Temperatures. Part 2: Numerical Simulation
N2 - Structural components of superconducting magnets (e.g., collars, bladders, or keys) with complex shapes, operating at cryogenic temperatures (4K, 77K), as well as additional elements of tanks for storing liquid hydrogen (20K), such as hoses and valves, are made of austenitic steel. With conventional manufacturing technologies, complex geometries are difficult to manufacture. In contrast, additive manufacturing offers the possibility of easier production of complex geometries, although the knowledge about the material behavior is not yet comprehensively available. The scientific objective of the project is the experimental identification and numerical simulation of the evolution of the deformation-induced martensitic transformation and the prediction of the material behavior of Fused Filemant Fabricated (FFF) 316L for cryogenic applications.
The material behavior of FFF-316L under tensile stress at both room temperature and 77K was characterized. Utilizing experimental data and microstructure analysis through scanning electron microscopy, a comprehensive material model [1] was used. This constitutive model is centered on the deformation-induced martensitic transformation at both ambient and cryogenic temperatures. The linear kinetic law of evolution of deformation-induced phase transformation in ASS is adopted [1]. It posits that the phase transformation is driven by the accumulated plastic strain. The model intricately links the intensity of plastic deformation to the phase transformation, employing a mixed kinematic/isotropic linear plastic hardening approach based on Mori-Tanaka homogenization. A numerical results will be verified experimentaly at room and at 77K.
T2 - 43rd Solid Mechanics Conference
CY - Wroclaw, Poland
DA - 16.09.2024
KW - Phase transformation
KW - Deformation-induced martensitic transformation
KW - 316L
KW - Fused Deposition Modelling
PY - 2024
AN - OPUS4-61181
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hohendorf, Stefan
T1 - Medea und Jason, Eine Radiologische Untersuchung im Neuen Palais Potsdam
N2 - Seit der Antike gehört die Medea-Sage zu den bekanntesten Geschichten der Weltliteratur. Der berühmte französische Künstler Carle Van Loo hat sich dieses Epos um 1759 angenommen und ein beeindruckendes Ölgemälde mit Abmessungen von 2,30x3,28m² erschaffen. Mit Mademoiselle Clairon als Medea und Henri Louis Le Kain als Jason ist ein Kunstwerk entstanden, das seitdem einige Veränderungen und Restaurierungen erfahren hat.
Die Bundesanstalt für Materialforschung und -prüfung (BAM) hatte 2020 die Möglichkeit, dieses und ein zweites Kunstwerk, im Neuen Palais in Potsdam, für die Stiftung Preußische Schlösser und Gärten Berlin-Brandenburg, radiografisch zu untersuchen. Hierbei wurden sowohl technologisch als auch kunsthistorisch einige interessante Entdeckungen gemacht, die im vorliegenden Beitrag vorgestellt werden.
T2 - DGZfP Jahrestatung 2022
CY - Kassel, Germany
DA - 23.05.2022
KW - Röntgen
KW - X-Ray
KW - Kunsstechnologisch
KW - Gemälde
KW - Untermalung
KW - Speicherfolie
KW - Strahlenschutz
PY - 2022
AN - OPUS4-56577
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Zhu, Jiangchao
A1 - Madia, Mauro
A1 - Schurig, M.
A1 - Schlums, H.
A1 - Zerbst, Uwe
T1 - Fracture mechanics-based structural integrity assessment of aeroengine turbine disks under overspeed conditions
N2 - Aero-engine turbine disks are safety-relevant components which are operated under high thermal and mechanical stress conditions. The actual part qualification and certification procedures make use of spin-tests conducted on productionsimilar disks. While these tests provide, on the one hand, a reliable definition of the critical conditions for real components, on the other hand they represent a relevant cost item for engine manufacturers. The aim of this work is to present part of a fracture mechanics-based procedure under development which aims at replacing the tests on production-similar disks with lab tests on fracture mechanics specimens. In particular, the rimpeeling failure mode is considered as case study. A semi-circular surface crack is modelled at the most stressed region at the diaphragm of a turbine disk, with the crack plane perpendicular to the radial direction. The crack is therefore subjected to a biaxial stress state and grows under increasing rotational speed until it triggers the rim-peeling failure. The finite element simulation of the cracked disk considers the real thermal and mechanical loading conditions. In order to design a lab representative specimen, beside the crack driving force, expressed in terms of � -integral, also the constraint to plastic deformation e.g., stress triaxiality, at the crack-tip must be similar for the same crack in the specimen and in the disk. This has been achieved and as expected, both the highest � -integral and constraint factor are calculated at the same location along the crack front for both disk and specimen. The results of the structural integrity assessment in the form of a Failure Assessment Diagram (FAD) show good agreement between designed specimen and disk both in terms of expected failure mode and value of the critical speed. Probabilistic aspects are also considered in the calculations.
T2 - ASME Turbo Expo 2022: Turbomachinery Technical Conference and Exposition (GT2022)
CY - Rotterdam, The Netherlands
DA - 13.06.2022
KW - Fracture mechanics
KW - Burst
KW - Turbine disk
PY - 2022
SP - 1
EP - 7
PB - ASME
AN - OPUS4-55903
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sechi, R.
A1 - Fackeldey, K.
A1 - Chewle, Surahit
A1 - Weber, M.
T1 - SepFree NMF: A toolbox for analyzing the kinetics of sequential spectroscopic data
N2 - This work addresses the problem of determining the number of components from sequential spectroscopic data analyzed by non-negative matrix factorization without separability assumption (SepFree NMF). These data are stored in a matrix M of dimension “measured times” versus “measured wavenumbers” and can be decomposed to obtain the spectral fingerprints of the states and their evolution over time. SepFree NMF assumes a memoryless (Markovian) process to underline the dynamics and decomposes M so that M = WH, with W representing the components’ fingerprints and H their kinetics. However, the rank of this decomposition (i.e., the number of physical states in the process) has to be guessed from pre-existing knowledge on the observed process. We propose a measure for determining the number of components with the computation of the minimal memory effect resulting from the decomposition; by quantifying how much the obtained factorization is deviating from the Markovian property, we are able to score factorizations of a different number of components. In this way, we estimate the number of different entities which contribute to the observed system, and we can extract kinetic information without knowing the characteristic spectra of the single components. This manuscript provides the mathematical background as well as an analysis of computer generated and experimental sequentially measured Raman spectra.
KW - Kinetics from experiments
KW - Separability assumption
KW - Sequential spectroscopic data
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-559046
DO - https://doi.org/10.3390/a15090297
SN - 1999-4893
VL - 15
IS - 9
SP - 1
EP - 16
PB - MDPI
CY - Basel
AN - OPUS4-55904
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Epperlein, Martin
T1 - Eine digital gestützte Qualitätssicherung für die additive Fertigung
N2 - Die Digitalisierung der Qualitätsinfrastruktur (QI) am Beispiel der Additiven Fertigung.
Der Vortrag erörtert, wie die Elemente einer digitalen QI zur Qualitätssicherung und Zertifizierung in der Additiven Fertigung beitragen können.
T2 - Treffen der Arbeitsgemeinschaft Additive Fertigung des VDMA
CY - Coburg, Germany
DA - 27.10.2022
KW - Qualitätsinfrastruktur
KW - Additive Fertigung
KW - Digitalisierung
PY - 2022
AN - OPUS4-56165
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Höhne, Patrick
T1 - Optimized spray granules for dry pressing by means of slurry destabilization and ultrasonic atomization
N2 - The homogeneous introduction of organic additives is a prerequisite for good processability of ceramic powders during dry pressing. The addition of organic additives by wet route via ceramic slurries offers advantages over dry processing. The organic content can be reduced and a more homogeneous distribution of the additives on the particle surface is achieved. In addition to the measurements of zeta potential and viscosity, sedimentation analysis by optical centrifugation was also tested and successfully used to characterize the ceramic slurries and accurately evaluate of the suitability of different types, amounts, and compositions of organic additives.
Spray drying of well-stabilized slurries usually results in mostly hollow granules with a hard shell leading to sintered bodies with defects and reduced strength and density. By purposefully degrading the slurry stability after dispersion of the ceramic powder, the drying behavior of the granules in the spray drying process and thus the granule properties can be influenced. Destabilization of the slurry and thus partial flocculation was quantified by optical centrifugation. Spray drying of the destabilized alumina slurries resulted in "non-hollow" granules without the detrimental hard shell and thus improved granule properties.
Further improvement of the granules was achieved by installing ultrasonic atomization in the spray dryer. A narrower granule size distribution was achieved, which had a positive effect on, among other things, the flowability of the granules.
Specimens produced from this granules had fewer defects of smaller size, leading to better results for the density and strength of the sintered bodies. The observations made for alumina could be transferred to zirconia and as well to ZTA with 20 wt% zirconia.
T2 - Ceramics in Europe 2022
CY - Krakau, Poland
DA - 10.07.2022
KW - Ultrasound
KW - Spray drying
KW - Slurry
PY - 2022
AN - OPUS4-56171
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bettge, Dirk
A1 - Klinger, Christian
T1 - Schadensanalyse an Fahrradkomponenten - Fraktographie, Ursachen, Prävention
N2 - Komponenten von Fahrrädern werden im Betrieb vorwiegend schwingend beansprucht. Typische Werkstoffe sind Stahl, Aluminiumlegierungen, Messing, CFK und thermoplastische Kunststoffe. Da es sich, unabhängig von der Preiskategorie, um konstruktiven Leichtbau handelt, werden einige Bauteile betriebsfest mehr oder weniger weit oberhalb der Dauerfestigkeit ausgelegt. Die im normalen Betrieb auftretenden Schäden sind daher weit überwiegend Schwingbrüche. Andere Schadensmechanismen wie z.B. Korrosion spielen quantitativ eine untergeordnete Rolle. Schwingbrüche treten nach einer Periode unbemerkten Risswachstums oft ohne Vorwarnung und ohne makroskopische Verformung auf. Im Falle von sicherheitsrelevanten Komponenten wie Rahmen, Gabeln, Lenkern, Sattelstützen, Kurbelarmen oder Pedalen kann dies zu erheblichen Personenschäden führen, die den Wert des ursächlichen Bauteilschadens weit überschreiten.
Über einen langjährigen Zeitraum wurden gebrochene Komponenten aus dem Alltag und aus Gerichtsverfahren analysiert. Das Hauptaugenmerk lag hierbei auf der fraktographischen Analyse, teilweise wurden die zu Grunde liegenden Schadensursachen ermittelt. Einflussfaktoren sind beispielsweise konstruktive Kerben an ungünstigen Stellen, aber auch Werkstoffwahl und Fertigungsqualität spielen eine Rolle. In den meisten Fällen wurde jedoch die konstruktive Lebensdauer überschritten. Diese wird praktisch nie mitgeteilt, und eine wiederkehrende Prüfung sicherheitsrelevanter Bauteile findet nicht statt.
Im Sinne der Vermeidung von Schäden und Unfällen könnte darauf hingewirkt werden, für sicherheitsrelevante Komponenten Lebensdauern besser abzuschätzen und von der Laufleistung abhängige Sichtprüfungen zu empfehlen.
T2 - DGM Tagung Werkstoffprüfung
CY - Dresden, Germany
DA - 26.10.2022
KW - Fraktographie
KW - Fahrrad
KW - Lebensdauer
KW - Öffentliche Sicherheit
KW - Schadensanalyse
KW - Schadensprävention
PY - 2022
AN - OPUS4-56122
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Braun, T.
T1 - Evaluation of electric conductivity and mechanical load capacity of copper deposits for application in large winding components for electrical high-voltage machines made with cold spray additive manufacturing
N2 - In line with the industrial trend of additive manufacturing, cold spray as a non-laser-based process is becoming increasingly important for many fields of application. For the evaluation of additive manufacturing of winding components made of copper for large electrical high-voltage machines, material and component properties such as electrical conductivity, mechanical load capacity and the component size that can be produced are of particular importance. In this context, the cold spray process offers advantages over laser-based additive manufacturing processes such as laser powder bed fusion (LPBF) or laser cladding by using the kinetic energy of the copper powder particles to generate particle cohesion. To investigate the electrical conductivity as well as the mechanical load capacity of cold spray parts, specimens were machined out of cold sprayed bulk copper deposits. The characteristic values were obtained with regard to the direction of deposition, which is defined by the direction of the robot’s movement. Thus, for the investigation of the component properties, specimens were provided that had been produced both longitudinally and transversely as well as orthogonally to the direction of deposition. The results of the investigations show that both the electrical conductivity and the mechanical load capacity of the specimen have a strong preferential direction of the specimen orientation with respect to the direction of deposition. Furthermore, it could be shown that by increasing the deposition height, there is an increasing oxygen content in the sample material, combined with increasingly significant defect networks. These effects have a negative impact on the electrical conductivity as well as on the mechanical load capacity. As a conclusion, further need for investigation is identified in the optimization of the process parameters as well as in the deposition strategy for the additive manufacturing of large-volume components with cold spray.
T2 - ITSC 2022
CY - Vienna, Austria
DA - 04.05.2022
KW - Cold Spray
KW - Copper powder particles
KW - Electrical conductivity
KW - Large electrical high-voltage machine
PY - 2022
AN - OPUS4-56127
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Braun, T.
A1 - Uhlmann, E.
A1 - Häcker, Ralf
A1 - Jäger, M.
A1 - Rauch, H.
A1 - Kondas, J.
A1 - Brach, K.
A1 - Singh, R.
T1 - Evaluation of electric conductivity and mechanical load capacity of copper deposits for application in large winding components for electrical high-voltage machines made with cold spray additive manufacturing
N2 - In line with the industrial trend of additive manufacturing, cold spray as a non-laser-based process is becoming increasingly important for many fields of application. For the evaluation of additive manufacturing of winding components made of copper for large electrical high-voltage machines, material and component properties such as electrical conductivity, mechanical load capacity and the component size that can be produced are of particular importance. In this context, the cold spray process offers advantages over laser-based additive manufacturing processes such as laser powder bed fusion (LPBF) or laser cladding by using the kinetic energy of the copper powder particles to generate particle cohesion. To investigate the electrical conductivity as well as the mechanical load capacity of cold spray parts, specimens were machined out of cold sprayed bulk copper deposits. The characteristic values were obtained with regard to the direction of deposition, which is defined by the direction of the robot’s movement. Thus, for the investigation of the component properties, specimens were provided that had been produced both longitudinally and transversely as well as orthogonally to the direction of deposition. The results of the investigations show that both the electrical conductivity and the mechanical load capacity of the specimen have a strong preferential direction of the specimen orientation with respect to the direction of deposition. Furthermore, it could be shown that by increasing the deposition height, there is an increasing oxygen content in the sample material, combined with increasingly significant defect networks. These effects have a negative impact on the electrical conductivity as well as on the mechanical load capacity. As a conclusion, further need for investigation is identified in the optimization of the process parameters as well as in the deposition strategy for the additive manufacturing of large-volume components with cold spray.
T2 - ITSC 2022
CY - Wien, Austria
DA - 04.05.2022
KW - Cold Spray
KW - Electrical conductivity
KW - Copper powder particles
KW - Large electrical high-voltage machine
PY - 2022
SP - 1
EP - 7
AN - OPUS4-56108
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pialat, A.
A1 - Kitos, A.
A1 - Witkowski, Tomasz
A1 - Cook, C.
A1 - Wang, S.
A1 - Hu, A.
A1 - Murugesu, M.
T1 - Achieving short ignition delay and high specific impulse with cyanoborohydride based hypergolic ionic liquids
N2 - The efficient design of hypergolic-ionic-liquid (HIL) fuels with attractive features, (e.g., short ignition delay and high specific impulse) can be achieved by fine-tuning the molecular organization comprising both cations with appropriate alkyl chains and cyanoborohydride-based hydrogen-rich anions. Attractive features of the presented derivatives were attained by combining cations with various substituents (substituted 1H-1,2,4-triazol-4-ium, pyrrolidinium, ammonium and pyridinium cations) and the cyanoborohydride anion. All shown HILs display high thermal stabilities with thermal decomposition temperatures over 154 °C and possess higher densities (from 0.82 to 1.02 g cm−3) compared to the unsymmetrical dimethylhydrazine (UDMH, 0.793 g cm−3). The hypergolic ignition behavior of the propellant combination was evaluated by a drop test setup using white fuming nitric acid (WFNA) as an oxidizer and recorded using a high-speed camera. All compounds feature ignition delay times (ID) under 50 ms, while the 1-hexyl-1-methylpyrrolidin-1-ium cyanotrihydroborate congener (17) exhibited the shortest ID time (5 ms), which is comparable to the ID time of UDMH (4.8 ms with WFNA as an oxidizer). In addition, these HILs exhibit higher heats of formation (187.6 to 392.6 kJ mol−1), heats of combustion (34.39 to 47.15 kJ g−1) and specific impulse (176 to 205 s) compared to UDMH.
KW - Hypergolic ionic liquids
PY - 2022
DO - https://doi.org/10.1039/D2NJ03372K
SN - 1144-0546
SP - 1
EP - 9
PB - RSC
CY - Cambridge
AN - OPUS4-56147
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Zhu, Jiangchao
T1 - Kennwertermittlung für die Bewertung der Integrität einer Turbinenscheibe bei Überdrehzahl
N2 - Turbinenscheiben sind thermisch und mechanisch hochbeanspruchte, sicherheitsrelevante Komponenten in Gasturbinen. Ihre Integrität wird in Bauteiltests unter Überdrehzahlbedingungen nachgewiesen. Kontext des Aufsatzes ist die Erarbeitung einer zusätzlichen Bewertungsebene auf der Grundlage von Versuchen unter monotoner Beanspruchung, die die Beanspruchung im Bauteil realistisch wiedergeben soll. Dazu werden zwei Typen von bruchmechanischen Proben anwendungsnah ausgelegt und aus einer Turbinenscheibe ausgeschnitten: Der erste Typ ist eine biaxiale Probe, die die Beanspruchung und den Dehnungsbehinderungszustand am Diaphragm der Turbinenscheibe abbildet, die zweite eine bruchmechanische Probe, die die einachsige Beanspruchung und den Dehnungsbehinderungszustand am Bore der Turbinenscheibe wiedergibt.
Im Rahmen eines Schadentoleranzansatzkonzepts ist anschließend jeweils ein halbelliptischer Riss an den genannten Stellen der Turbinenscheibe zu betrachten. Mittels numerischer Berechnungen wird ein kritischer Punkt auf der Rissfront des Risses am Diaphragm bestimmt, dort wo die höchste Rissspitzenbelastung (J-Integral) auftritt. Auf der Basis der Rissspitzenbelastung, des Dehnungsbehinderungszustands und des entsprechenden Spannungsverhältnisses an diesem kritischen Punkt wird eine Kreuzprobe mit einem Durchriss konzipiert, die diese Verhältnisse im Bauteil widerspiegelt. Die Versuche werden unter der Temperatur am Diaphragm der Turbinenscheibe durchgeführt. Die J-R-Kurve und die plastische Kollapsgrenze werden bestimmt. Auch die einachsigen Versuche werden unter der Temperatur am Bore der Turbinenscheibe durchgeführt. Die Zugprobe enthält halbelliptische Oberflächenrisse. Ähnlich wie bei der Auslegung der Kreuzproben werden die Rissspitzenbelastung, der Dehnungsbehinderungszustand und das Spannungsverhältnis vergleichbar mit der Turbinenscheibe eingestellt. Die J-R-Kurve und die plastische Kollapsgrenze werden bestimmt.
Mit den Versuchsergebnissen werden die kritischen Lasten für verschiedene Versagensmechanismen (instabiles Risswachstum, plastischer Kollaps) der bruchmechanischen Proben ermittelt, die der kritischen Überdrehzahl der Turbinenscheibe entsprechen.
T2 - 40. Vortrags- und Diskussionstagung Werkstoffprüfung 2022
CY - Dresden, Germany
DA - 27.10.2022
KW - Turbine disk
KW - Fracture mechanics
KW - Biaxial test
KW - Burst
PY - 2022
AN - OPUS4-56148
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Heßmann, Jennifer
T1 - New approach for multi material design: combination of laser beam and electromagnetic melt pool displacement by induced lorentz forces
N2 - Multi-material structures are a promising solution to reduce vehicle weight and save fuel or electric energy in automotive design. However, thermal joining of steel and aluminum alloys is a challenge to overcome due to different material properties and the formation of brittle intermetallic phases. In this study, a new joining approach for producing overlap line-shaped joints is presented. The lower joining partner (EN AW 5754) is melted by a laser beam and this melt is displaced into a line-shaped cavity of the upper joining partner (1.0330) by induced Lorentz forces. The melt solidifies in the cavity to a material and form-fitting joint. This approach needs no auxiliary joining elements or filler materials. Previous investigation to produce spot-shaped joints by using this approach showed that quality and reproducibility were limited by known melt pool dynamics of aluminum alloys (keyhole collapses). For line-shaped joints, the melt displacement can take place behind the keyhole. This allows the displacement process to be spatial uncoupled from the influence of the keyhole collapses. The study shows that this improved the process stability and the quality of the joint. The created line-shaped joints were microstructurally characterized by transversal sections. Intermetallic phases were identified by electron backscatter diffraction (EBSD) and EDX-Analysis. The detected intermetallic phases consist of a 5 µm - 6 µm compact phase seam of Al5.6Fe2 and a needle shaped phase of Al13Fe4. Tensile shear tests were carried out to quantify the load capacity. It was possible to create a joint with a load capacity of about 2 kN.
T2 - ICALEO Orlando 2022
CY - Orlando, Florida, USA
DA - 17.10.2022
KW - Electromagnetic forces
KW - Joining dissimilar materials
KW - Laser beam welding
KW - Steel and aluminium
PY - 2022
AN - OPUS4-56149
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Krüger, Jörg
T1 - Strahlenschutz beim Umgang mit Ultrakurzpuls-Lasern
N2 - Ultrakurzpuls-Lasertechnik ist heute der Schlüssel für eine Vielzahl von Anwendungen in der industriellen Lasermaterialbearbeitung. Beim Einsatz hoher Laser-Intensitäten kann allerdings unerwünschte Röntgenstrahlung erzeugt werden. Die Röntgendosis und Energieverteilung ist von Laser-, Material- und Prozessparametern abhängig. Es können Röntgendosen über den erlaubten Grenzwerten für die Exposition des Menschen erreicht werden.
T2 - Kolloquium des Bundesamtes für Strahlenschutz (BfS)
CY - Online meeting
DA - 29.09.2022
KW - Ultrakurze Laserpulse
KW - Materialbearbeitung
KW - Röntgenstrahlung
KW - Strahlenschutz
KW - Abschirmung
PY - 2022
AN - OPUS4-55893
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Raute, J.
A1 - Marquardt, R.
A1 - Biegler, M.
A1 - Rethmeier, Michael
T1 - Untersuchung zum Elektronenstrahlschweißen additiv gefertigter Ni-Basis-Bauteile
N2 - Die vorliegende Untersuchung befasst sich mit dem Einfluss des Additive Manufacturing auf die Schweißeignung von Bauteilen aus Inconel 718. Hierfür wurden Proben mittels DED und L-PBF hergestellt und ihr Verhalten in Blindschweißversuchen anhand eines Vergleichs mit konventionellen Gussblechen untersucht. Im zweiten Schritt wurden die verschiedenen additiv hergestellten Proben mit dem Gussmaterial im I-Stoß sowie untereinander verschweißt.
Als Schweißverfahren wurde für alle Proben das Elektronenstrahlschweißen angewandt. Zur Auswertung wurde anhand von Schliffen das Nahtprofil vermessen und die Proben auf Poren und Risse untersucht. Zusätzlich wurde die Dichte vermessen und eine Prüfung auf Oberflächenrisse durchgeführt. Das AM-Material zeigte dabei Unterschiede in Nahtform und Defektneigung im Vergleich zum Gusswerkstoff. Insbesondere die DED-proben neigten unter bestimmten Parameterkonstellationen verstärkt zu Porenbildung. Risse konnten nicht beobachtet werden. Trotz auftretender Nahtunregelmäßigkeiten wurde in den kombinierten AM-Schweißproben die Bewertungsgruppe C erreicht. Eine Prüfung der bestehenden Regelwerke zur Schweißnahtbewertung anhand der gewonnenen Erkenntnisse zu additiv gefertigten Proben im Elektronenstrahlschweißprozess zeigte keinen Ergänzungsbedarf.
T2 - #additivefertigung: Metall in bestForm
CY - Essen, Germany
DA - 26.10.2022
KW - Elektronenstrahlschweißen
KW - Additive Fertigung
KW - Schweißnahtbewertung
PY - 2022
SN - 978-3-96144-202-7
VL - 383
SP - 81
EP - 92
PB - DVS-Media GmbH
AN - OPUS4-56173
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ewert, U.
A1 - Jaenisch, Gerd-Rüdiger
A1 - Schumacher, David
A1 - Zscherpel, U.
A1 - Deresch, A.
A1 - Bircher, B.
A1 - Meli, F.
T1 - Schnelle Messung und tomographische Rekonstruktion von Brennflecken < 5 μm durch Aufnahmen strukturierter Prüfkörper
N2 - Im Europäischen EMPIR-Projekt „NanoXSpot“ (Measurement of the focal spot size of Xray tubes with spot sizes down to 100 nm) werden neue Messmethoden für Brennflecke von Röntgenröhren entwickelt. Teil des Projektes ist die Entwicklung eines zur Lochkameramethode äquivalenten Messverfahrens für kleine Brennflecke. ASTM E 1165-20, Annex A, beschreibt die Bestimmung von Brennfleckgrößen aus Kantenprofilen von Lochaufnahmen für Röntgenröhren mit Brennflecken > 50 μm. Es wurde bereits vorgeschlagen über die Analyse der richtungsabhängigen Kantenunschärfe einer Lochblende und anschließender CT-Rekonstruktion die Intensitätsverteilung des Brennflecks äquivalent zur Lochkameraaufnahme zu berechnen. Die Lochkameramethode, wie in EN 12543-2 und ASTM E 1165-20 beschrieben, ist im unteren Größenbereich für Mikrofokusröhren nicht geeignet, da Pinholes < 10 μm schwer zu fertigen sind und lange Belichtungszeiten erwartet werden. Mit Hilfe exakt gefertigter Lochblenden sowie strukturierter Targets mit
konvergierenden Strukturen wird der Bereich mit der Single-Shot-CT-Methode auf die Messung von Mikrofokusröhren, alternativ zur Vermessung von Kanten oder Strichgruppenkörpern, erweitert. Die rekonstruierten Brennfleckformen werden mit Kantenund Lochkameraaufnahmen quantitativ verglichen, um die Messgenauigkeit zu bewerten.
Außerdem werden CNR und Messzeit bestimmt, um die Wirtschaftlichkeit der Verfahren zu bewerten.
T2 - DGZfP-Jahrestagung
CY - Online meeting
DA - 10.05.2021
KW - Röntgenröhre
KW - Brennfleckmessung
KW - Prüfkörper
KW - Rekonstruktion
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-561846
SP - 1
EP - 2
AN - OPUS4-56184
LA - deu
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 - CONF
A1 - Schartel, Bernhard
T1 - Weathering Resistance of Halogen-free Flame Retardancy in E&E Plastics
N2 - - Durability of fire retardancy
- Impact of different exposure conditions
- Degradation with respect to different fire properties/tests
T2 - Fire Resistance in Plastics
CY - Cologne, Germany
DA - 28.11.2022
KW - Durability
KW - Flame retardant
KW - Thermoplastic Polyurethane
KW - Cable
KW - EVA
KW - Weathering
PY - 2022
AN - OPUS4-56444
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -