TY - JOUR
A1 - Müller, Bernd R.
A1 - Lange, Axel
A1 - Harwardt, Michael
A1 - Hentschel, Manfred P.
A1 - Illerhaus, Bernhard
A1 - Goebbels, Jürgen
A1 - Bamberg, J.
A1 - Heutling, F.
T1 - Refraction computed tomography - Application to metal matrix composites
N2 - Erstmals wurden MMCs mit Hilfe der Interface-Kontrast verstärkenden Röntgen-Refraktions-Technik in Kombination mit der 3D-CT-Technik untersucht. Die Methode der Röntgen-Refraktions-Topography sowie der Röntgen-Refraktions-Tomography wurden in den letzten Jahren speziell für die zerstörungsfreie Charakterisierung von Leichtbau-Hochleistungs-Werkstoffen wie Verbund-Werkstoffen und Keramiken entwickelt. Die Technik basiert auf der Refraktion von Röntgenlicht an Grenzflächen zwischen Bereichen unterschiedlicher Elektronendichte wie z.B. Faser- und Matrix-Werkstoff. Auf Grund der kurzen Röntgen-Wellenlänge hat der Brechungsindex einen Wert dicht bei eins, sodass der Streuwinkel nur wenige Bogenminuten beträgt. Der Vorteil der kurzen Wellenlänge besteht jedoch darin, dass Poren und Risse detektiert werden können, deren Größe im Nanometerbereich liegen. Damit kann die Refraktions-Technik zum besseren Verständnis von Mikro- und Submikro-Strukturen in der Materialwissenschaft eingesetzt werden. Mit der hier vorgestellten Refraktions-CT wurden Ermüdungsmechanismen an MMCs, bestehend aus SiC-Faser verstärktem Titan (Ti6242) untersucht. Die Messungen wurden am Röntgen-Messplatz der BAM (BAMline) am Synchrotron-Speicherring-BESSY in Berlin Adlershof durchgeführt.
KW - X-ray refraction
KW - Computed tomography
PY - 2004
DO - https://doi.org/10.3139/120.100592
SN - 0025-5300
VL - 46
IS - 6
SP - 314
EP - 319
PB - Carl Hanser Verlag
CY - München
AN - OPUS4-5870
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Müller, Bernd R.
A1 - Lange, Axel
A1 - Harwardt, Michael
A1 - Hentschel, Manfred P.
A1 - Illerhaus, Bernhard
A1 - Goebbels, Jürgen
A1 - Bamberg, J.
A1 - Heutling, F.
T1 - 3D Refraction Computed Tomography Applied to Metal Matrix Composites
N2 - For the first time Metal Matrix Composites (MMC) have been investigated by 3D Computed Tomography combined with enhanced interface contrast due to X-ray refraction. X-ray refraction is a relatively new approach for the characterization of advanced materials. The related techniques of Refraction Topography and Refraction Computed Tomography have been developed and applied at our laboratory during the last decade to meet the actual demand for improved nondestructive characterization of high performance composites, ceramics and other low density materials and components. X-ray refraction occurs, when X-rays crosses interfaces of spherical or cylindrical shape (e.g. pores or fibres) in the same way as visible light is refracted by lenses. These X-ray optical effects can be observed at small scattering angles of few minutes of arc as the refractive index n of X-rays is nearly unity (n = 1 10-6). Due to the short X-ray wavelength of about 0.1 nm the technique determines the amount of inner surfaces and interfaces of nanometer dimensions. The technique is expected to solve many problems in understanding the meaning of micro and sub micro structures in materials science. With the results of the CT investigation, some questions could be clarified for a better understanding of fatigue failure mechanisms under cyclic loading conditions. The specimens for the test programme have been provided by MTU Aero Engines. They consist of a titanium matrix (Ti6242) reinforced by SiC fibres (SCS6). The investigations have been performed at the materials research station of BAM (BAMline) at the Synchrotron Facility BESSY in Berlin, Germany.
T2 - 35th International SAMPE technical conference
CY - Dayton, OH, USA
DA - 2003-09-28
KW - Non-Destructive Inspection (NDI)
KW - Characterization
KW - Titanium Metal Matrix Composites (Ti-MMC)
KW - Ti6242
KW - SCS6
PY - 2003
SN - 0-938994-95-6
PB - SAMPE
CY - Covina, Calif.
AN - OPUS4-2780
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Röhrich, J.
A1 - Damerow, T.
A1 - Hahn, W.
A1 - Müller, U.
A1 - Reinholz, Uwe
A1 - Denker, A.
T1 - A tandetron as proton injector for the eye tumor therapy in Berlin
N2 - The therapy of eye tumors with fast protons is an excellent tool giving very high local control rates. At the Helmholtz-Zentrum Berlin (HZB) almost 1800 patients were treated since 1998. A 2 MV Tandetron was installed as injector for the k = 132 HZB cyclotron. Using the standard 358 duoplasmatron ion source with direct extraction of negative hydrogen ions an extremely stable proton beam can be delivered, both on the short-term and the long-term scale. The hair-needle filaments made from thoriated tungsten wires have safe operation times of more than 1000 h.
KW - Biomedical equipment
KW - Duoplasmatrons
KW - Eye
KW - Particle beam extraction
KW - Radiation therapy
KW - Tumours
PY - 2012
DO - https://doi.org/10.1063/1.3662475
SN - 0034-6748
SN - 1089-7623
VL - 83
IS - 02B903
SP - 1
EP - 3
PB - American Institute of Physics
CY - Melville, NY
AN - OPUS4-25721
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tielemann, Christopher
A1 - Reinsch, Stefan
A1 - Maaß, Robert
A1 - Deubener, J.
A1 - Müller, Ralf
T1 - Internal nucleation tendency and crystal surface energy obtained from bond energies and crystal lattice data
N2 - We present an easy-to-apply method to predict structural trends in the internal nucleation tendency of oxide glasses. The approach is based on calculated crystal fracture surface energies derived from easily accessible diatomic bond energy and crystal lattice data. The applicability of the method is demonstrated on literature nucleation data for isochemically crystallizing oxide glasses.
KW - Glass
KW - Nucleation tendency
KW - Fracture surface energy
KW - Crystal lattice
KW - Bond energy
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-548814
DO - https://doi.org/10.1016/j.nocx.2022.100093
SN - 2590-1591
VL - 14
SP - 1
EP - 5
PB - Elsevier B.V.
AN - OPUS4-54881
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Seifert, Lando
A1 - Philipp, M.
A1 - Ebell, Gino
A1 - Moersch, J.
A1 - Müller, Thoralf
T1 - Gemeinsamer Schlussbericht zum Forschungsvorhaben - Entwicklung eines neuen Prüfverfahrens zur Beurteilung der Spannungsrisskorrosionsempfindlichkeit von Spannstählen für den Spannbetonbau
N2 - Für die Sicherheit von Spannbetonbauwerken ist eine Empfindlichkeitsprüfung von Spannstahlprodukten gegenüber der wasserstoffinduzierten Spannungsrisskorrosion zwingend erforderlich. Die derzeitig normativ festgelegten Prüfmethoden nach DIN EN ISO 15630-3 zeigen nachweislich Schwächen hinsichtlich der Reproduzierbarkeit der Ergebnisse und erschweren damit die eindeutige Bewertung der Empfindlichkeit. Ziel des Forschungsvorhabens der Förderinitiative WIPANO des BMWK war es, die Prüfmethode hinsichtlich der Reproduzierbarkeit und Aussagesicherheit zu verbessern. Im Projekt wurden durch materialseitige, elektrolytische und verfahrenstechnische Parameteränderungen konstante und reproduzierbare Prüfbedingungen geschaffen. Dies ermöglichte eine eindeutige Differenzierung zwischen Gut- und Schlechtprodukten. Innerhalb des Projekts wurde ein Ringversuch initiiert, welcher die Anwendbarkeit und Reproduzierbarkeit der neuen Prüfmethode bestätigte. Das neue Prüfverfahren wurde hinsichtlich der Anwendbarkeit für das Spannstahlerzeugnis Draht evaluiert. Ein entsprechender Normentwurf mit einem Vorschlag für ein Konformitätskriterium dieser Erzeugnisse wurde dem zuständigen ISO-Gremium präsentiert und zur Abstimmung überlassen. Nach aktueller Rückmeldung seitens des Gremiums wird der Normentwurf den Eingang in den informativen Anhang der Prüfnorm finden, dies könnte den Weg für eine Spiegelung auf europäischer und nationaler Normungsebene ebnen.
KW - Spannstahl
KW - Spannungsrisskorrosion
KW - ISO 15630-3
KW - Wasserstoff
KW - Permeationsmessung
KW - WIPANO
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-577922
DO - https://doi.org/10.26272/opus4-57792
SP - 1
EP - 106
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-57792
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Herzel, Hannes
A1 - Dombinov, V.
A1 - Vogel, Christian
A1 - Willbold, S.
A1 - Levandowski, G. V.
A1 - Meiller, M.
A1 - Müller, F.
A1 - Zang, J. W.
A1 - da Fonseca-Zang, W. A.
A1 - Jablonowski, N. D.
A1 - Schrey, S. D.
A1 - Adam, Christian
T1 - Soybean Fertilized by P-Phases from Bagasse-Based Materials: P-Extraction Procedures, Diffusive Gradients in Thin Films (DGT), and X-ray Diffraction Analysis (XRD)
N2 - The Brazilian sugarcane industry produced around 173 million tons (Mt) of bagasse in 2018. Bagasse is a by-product of juice extraction for ethanol and sugar production and is combusted in order to generate power, producing up to 10 Mt of ash per year. This ash contains various concentrations of plant nutrients, which allow the ash to be used as a crop fertilizer. However, the concentration and extractability of phosphorus (P), an essential plant nutrient, are low in bagasse ash. To increase the P content, we co-gasified and co-combusted bagasse with P-rich chicken manure. The resulting ash was thermochemically post-treated with alkali additives (Na2SO4 and K2SO4) to increase the availability of P to plants. We aimed to: (i) investigate the effect of thermochemical post-treatment of co-gasification residue and co-combustion ash on P availability to soybeans, (ii) explore the potential of chemical extraction methods (citric acid, neutral ammonium citrate, formic acid, and Mehlich-I) and diffusive gradients in thin films (DGT) to predict the availability of P to soybeans, and (iii) identify the responsible P-phases using X-ray diffraction . We evaluated P availability to soybeans growing in Brazilian Oxisol soil in two independent greenhouse pot experiments. The positive effect of thermochemical treatment on P availability from gasification residue was confirmed through the observation of increased P uptake and biomass in soybean plants. These findings were confirmed by chemical extraction methods and DGT. The gasification residue contained whitlockite as its main P-bearing phase. Thermochemical post-treatment converted whitlockite into highly soluble CaNaPO4. In contrast, co-combustion ash already contained highly soluble Ca(Na,K)PO4 as its main P-bearing phase, making thermochemical post-treatment unnecessary for increasing P availability. In conclusion, increased extractability and availability of P for soybeans were closely connected to the formation of calcium alkali phosphate. Our findings indicate that this combined methodology allows for the prediction of P-fertilization effects of ash.
KW - Sugar cane bagasse
KW - Chicken manure ash
KW - Thermochemical treatment
KW - Nutrient
KW - Plant availability
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509735
DO - https://doi.org/10.3390/agronomy10060895
VL - 10
SP - 895
EP - 6
PB - MDPI
AN - OPUS4-50973
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller, Christina
A1 - Bertovic, Marija
A1 - Pavlovic, Mato
A1 - Kanzler, Daniel
A1 - Ewert, Uwe
A1 - Pitkänen, J.
A1 - Ronneteg, U.
T1 - Holistically evaluating the reliability of NDE systems - paradigm shift
N2 - New methodologies for evaluating the reliability of NDE systems are discussed in accordance with the specific requirements of industrial application. After a review of the substantive issues from the previous decades, the go forward guidance is concluded. For high safety demands a quantitative probability of detection (POD) created from hit miss experiments or signal response analysis and ROC (Receiver Operating Characteristics) are typically created. The modular model distinguishes between the influence of pure physics and technique, industrial application factors and the human factor and helps to learn what factors are covered by modelling, open or blind trials. A new paradigm is offered to consider the POD or reliability of the system as a function of the configuration of input variables and use it for optimisation rather than for a final judgement. New approaches are considered dealing with real defects in a realistic environment, affordable but precisely like the Bayesian approach or model assisted methods. Among the influencing parameters, the human factor is of high importance. A systematic psychological approach helps to find out where the bottlenecks are and shows possibilities for improvement.
T2 - 18th WCNDT - World conference on nondestructive testing
CY - Durban, South Africa
DA - 16.04.2012
KW - Reliability of NDE
KW - POD
KW - ROC
KW - Modular Model
KW - Multiparameter-POD
KW - Bayesian Approach
KW - Human Factor
PY - 2012
SN - 978-0-620-52872-6
SP - 1
EP - 14 (Paper 591)
AN - OPUS4-27579
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dombinov, V.
A1 - Herzel, Hannes
A1 - Meiller, M.
A1 - Müller, F.
A1 - Willbold, S.
A1 - Zang, J. W.
A1 - da Fonseca-Zang, W. A.
A1 - Adam, Christian
A1 - Klose, H.
A1 - Poorter, H.
A1 - Jablonowski, N. D.
A1 - Schrey, S. D.
T1 - Sugarcane bagasse ash as fertilizer for soybeans: Effects of added residues on ash composition, mineralogy, phosphorus extractability and plant availability
N2 - Sugarcane bagasse is commonly combusted to generate energy. Unfortunately, recycling strategies rarely consider the resulting ash as a potential fertilizer. To evaluate this recycling strategy for a sustainable circular economy, we characterized bagasse ash as a fertilizer and measured the effects of co-gasification and co-combustion of bagasse with either chicken manure or sewage sludge: on the phosphorus (P) mass fraction, P-extractability, and mineral P phases. Furthermore, we investigated the ashes as fertilizer for soybeans under greenhouse conditions. All methods in combination are reliable indicators helping to assess and predict P availability from ashes to soybeans. The fertilizer efficiency of pure bagasse ash increased with the ash amount supplied to the substrate. Nevertheless, it was not as effective as fertilization with triple-superphosphate and K2SO4, which we attributed to lower P availability. Co-gasification and co-combustion increased the P mass fraction in all bagasse-based ashes, but its extractability and availability to soybeans increased only when co-processed with chicken manure, because it enabled the formation of readily available Ca-alkali phosphates. Therefore, we recommend co-combusting biomass with alkali-rich residues to increase the availability of P from the ash to plants.
KW - Combustion and gasification
KW - Phosphate extractability and availability
KW - X-ray diffraction (XRD)
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-567632
DO - https://doi.org/10.3389/fpls.2022.1041924
SN - 1664-462X
VL - 13
SP - 1
EP - 13
PB - Frontiers Media
CY - Lausanne
AN - OPUS4-56763
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Müller, U.
A1 - McMahon, Dino Peter
A1 - Rolff, J.
T1 - Exposure of the wild bee Osmia bicornis to the honey bee pathogen Nosema ceranae
N2 - Wild bees are important pollinators for agricultural crops and solitary species such as Osmia bicornis are particularly suitable for pollination management. Wild bees share floral resources with managed honey bees and may be exposed to emerging infectious diseases. Although studies have explored the prevalence of pathogens in solitary wild bee species, data regarding the impact of pathogens on solitary bee health are lacking.
We carried out experiments examining whether the solitary bee species O. bicornis is susceptible to infection with the emerging pathogen The results obtained indicate that N. ceranae may be able to infect O. bicornis but its impact on host fitness is negligible: survival rates did not differ between Control and inoculated bees, although male survival was marginally lower after infection. To explore the possible field-relevance of our findings, we collected wild bees near an infected and a non-infected hive and showed that N. ceranae was shared between managed and wild bees, although only the in presence of infected honey bees.
The findings of the present study show that O. bicornis is susceptible to pathogen spillover and could act as a potential reservoir host for N. ceranae in pollinator networks. Additional studies on this species incorporating sublethal effects, multiple infections and other interacting stressors are warranted.
KW - Wild bees
KW - Nosema ceranae
KW - Osmia bicornis
KW - Pathogen spillover
KW - Survival rates
PY - 2019
DO - https://doi.org/10.1111/afe.12338
SN - 1461-9555
SN - 1461-9563
VL - 21
IS - 4
SP - 363
EP - 371
PB - Wiley
AN - OPUS4-49648
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Welter, T.
A1 - Marzok, Ulrich
A1 - Deubener, J.
A1 - Reinsch, Stefan
A1 - Müller, Ralf
T1 - Hydrogen diffusivity in sodium aluminosilicate glasses
N2 - Hydrogen gas diffusivity of fourteen glasses of the Na2O-Al2O3-SiO2 system are studied along the joins quartzalbite-jadeite-nepheline (Qz-Ab-Jd-Np, fully polymerized) and albite-sodium disilicate (Ab-Ds, depolymerized).
Density measurements show that ionic porosity decreases from 54.4% (Qz) to 51.5% (Np) and from 52.4% (Ab) to 50.2% (Ds). Hydrogen diffusivity D follows similar trends but at another scale. D at 523 K decreases from 4×10−12 to 3×10−14m2 s−1 (Qz-Np) and from 4×10−13 to 3×10−15m2 s−1 (Ab-Ds). Charge compensating Na+ acting as a filling agent in fully polymerized network structures leads to up to one order of Magnitude higher diffusivities as depolymerized glass structures of the same SiO2 content where Na+ takes the role of a
modifier ion. Temperature dependence of the diffusivity indicates that both the activation energy involved with the moving H2 molecule as well as the accessible volume in the structure contribute to this compositional trend.
KW - Aluminosilicate glasses
KW - Hydrogen diffusivity
KW - Ionic porosity
PY - 2019
DO - https://doi.org/10.1016/j.jnoncrysol.2019.119502
VL - 521
SP - 119502
PB - Elsevier B.V.
AN - OPUS4-50392
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kiefer, P.
A1 - Deubener, J.
A1 - Müller, Ralf
A1 - Behrens, H.
T1 - Statistical analysis of propagation rates of indentation-induced radial cracks
N2 - Due to the stochastic nature of crack nucleation by Vickers indentation, a statistical analysis of propagation rates of 185 radial cracks was performed. Crack growth was observed directly using a video camera with high Image acquisition rate. It is found that propagation rates are controlled by the environmental reactions at the crack-tip shortly after their initiation (< 1 s). Calibration of the stress intensity KI showed that the residual stress factor χ and the exponent n of the equation KI==χPc−n (with P==load and c==crack length) are broadly distributed among the 185 analyzed cracks, ranging from 10−16 to 104 and from 0.1 to 5, respectively. For the most frequent crack, the equation KI==0.052Pc−1.47 holds. The results show that correlations of indentation-induced crack length to stress intensity necessitate the use of statistical significant data that are calibrated by the environmental reactions at the crack-tip.
KW - Stress intensity factor
KW - Vickers indentation
KW - Subcritical crack growth
KW - Soda-lime-silica glass
PY - 2019
DO - https://doi.org/10.1016/j.jnoncrysol.2019.119739
VL - 527
SP - 119739
PB - Elsevier B.V.
AN - OPUS4-50393
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller, I.
A1 - Moll, J.
A1 - Kexel, C.
A1 - Schubert, L.
A1 - Tschöke, K.
A1 - Prager, Jens
A1 - Lugovtsova, Yevgeniya
A1 - Bach, M.
A1 - Vogt, T.
T1 - SHM using Guided Waves – Recent Activities and Advances in Germany
N2 - Issues that prevent Structural Health Monitoring (SHM) based on Guided Waves (GW) from being a part of today’s monitoring solutions in industry are not all obvious to the scientific community. To uncover and overcome these issues, scientists working on SHM and GW problems joined in an expert committee under the patronage of the German Society for Non-Destructive Testing. An initiated online survey among more than 700 experts and users reveals the hurdles hindering the practical application of GWbased SHM. Firstly, methods for proof of reliability of SHM approaches are missing.
Secondly, detailed understanding of phenomenological described wave-damage interactions is needed. Additionally, there are significant unsolved implementation issues and unsolved problems of signal processing including handling of environmental influences.
To enable substantial proof of reliability without unaffordable experimental effort also efficient simulation tools including realistic damage interaction are needed, enabling the joint use of experimental and simulated data to predict the capabilities of the Monitoring system. Considering these issues, the committee focusses on simulation, signal processing, as well as probability of detection and standardization. In the presented work, recent activities of the expert committee starting with survey results are summarized. An open access data basis of life-like measurements is presented to allow testing and comparison of signal processing and simulation algorithms. Finally, a strategy for efficient proof of reliability increasing the acceptance of SHM in industry and for successful Integration of SHM into real-world engineering structures is proposed.
T2 - The 12th International Workshop on Structural Health Monitoring (IWSHM)
CY - Stanford, California, USA
DA - 10.09.2019
KW - Structural Health Monitoring
KW - Ultrasonic Guided Waves
KW - Non-Destructive Testing
KW - Survey
KW - Probability of Detection
KW - Reliability
PY - 2019
SP - 1
EP - 10
AN - OPUS4-49232
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Liens, A.
A1 - Reveron, H.
A1 - Douillard, T.
A1 - Blanchard, N.
A1 - Lughi, V.
A1 - Sergo, V.
A1 - Laquai, René
A1 - Müller, Bernd R.
A1 - Bruno, Giovanni
A1 - Schomer, S.
A1 - Fürderer, T.
A1 - Adolfsson, E.
A1 - Courtois, N.
A1 - Swain, M.
A1 - Chevalier, J.
T1 - Phase transformation induces plasticity with negligible damage in ceria-stabilized zirconia-based ceramics
N2 - Ceramics and their composites are in general brittle materials because they are predominantly made up of ionic and covalent bonds that avoid dislocation motion at room temperature. However, a remarkable ductile behavior has been observed on newly developed 11 mol.% ceria-stabilized zirconia (11Ce-TZP) composite containing fine alumina (8 vol.% Al2O3) and elongated strontium hexa-aluminate (8 vol.% SrAl12O19) grains. The as-synthesized composite also has shown full resistance to Low Temperature Degradation (LTD), relatively high strength and exceptionally high Weibull modulus, allowing its use in a broader range of biomedical applications. In this study, to deepen the understanding of plastic deformation in Ce-TZP based composites that could soon be used for manufacturing dental implants, different mechanical tests were applied on the material, followed by complete microstructural characterization. Distinct from pure Ce-TZP material or other zirconia-based ceramics developed in the past, the material here studied can be permanently strained without affecting the Young modulus, indicating that the ductile response of tested samples cannot be associated to damage occurrence. This ductility is related to the stress-induced tetragonal to monoclinic (t-m) zirconia phase transformation, analogue to Transformation-Induced Plasticity (TRIP) steels, where retained austenite is transformed to martensite. The aim of this study is to corroborate if the observed plasticity can be associated exclusively to the zirconia t-m phase transformation, or also to microcraking induced by the transformation. The t-m transformed-zones produced after bending and biaxial tests were examined by X-ray refraction and SEM/TEM coupled with Raman. The results revealed that the observed elastic-plastic behavior occurs without extensive microcracking, confirming a purely elastic-plastic behavior driven by the phase transformation (absence of damage).
KW - Zirconia
KW - Ceria
KW - Ceramic matrix composite
KW - Plasticity
KW - Phase transformation
KW - X-Ray Refraction
PY - 2020
UR - http://www.sciencedirect.com/science/article/pii/S1359645419307177
DO - https://doi.org/10.1016/j.actamat.2019.10.046
SN - 1359-6454
VL - 183
SP - 261
EP - 273
PB - Elsevier Ltd.
AN - OPUS4-49740
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Laquai, René
A1 - Müller, Bernd R.
A1 - Kasperovich, G.
A1 - Requena, G.
A1 - Haubrich, J.
A1 - Bruno, Giovanni
T1 - Classification of defect types in SLM Ti-6Al-V4 by X-ray refraction topography
N2 - Porosity in additively manufactured materials, such as laser powder bed fusion Ti-Al6-V4, can play an important role in their mechanical performance. Not only the total porosity but also the shape/morphology of the individual pores need to be considered. Therefore, it is necessary to determine the distributions of different defect types (especially fusing defects and keyhole pores) and their dependence on process parameters. We show that synchrotron X-ray refraction radiography allows analysis of large samples (up to several millimeters) without compromising the detectability of submicrometer defects. Correspondingly, a classification tool is introduced that is able to quantitatively distinguish defects such as keyhole pores and binding defects with a confidence level of 94 %, even when the shape cannot be discerned because of limited spatial resolution.
KW - Additive manufacturing
KW - Selective laser melting
KW - X-ray refraction
KW - Microscopy
KW - Porosity
KW - X-ray computed tomography
KW - BAMline
KW - Synchrotron Radiation
PY - 2020
DO - https://doi.org/10.1520/MPC20190080
SN - 2379-1365
VL - 9
IS - 1
SP - 82
EP - 93
PB - ASTM International
CY - West Conshohocken, PA
AN - OPUS4-50470
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cant, D. J. H.
A1 - Minelli, C.
A1 - Sparnacci, K.
A1 - Müller, Anja
A1 - Kalbe, H.
A1 - Stoger-Pollach, M.
A1 - Unger, Wolfgang
A1 - Werner, W. S. M.
A1 - Shard, A. G.
T1 - Surface-Energy Control and Characterization of Nanoparticle Coatings
N2 - Accurate and reproducible measurement of the structure and properties of high-value nanoparticles is extremely important for their commercialization. A significant proportion of engineered nanoparticle systems consist of some form of nominally core-shell structure, whether by design or unintentionally. Often, these do not form an ideal core-shell structure, with typical deviations including polydispersity of the core or shell, uneven or incomplete shells, noncentral cores, and others. Such systems may be created with or without intent, and in either case an understanding of the conditions for formation of such particles is desirable. Precise determination of the structure, composition, size, and shell thickness of such particles can prove challenging without the use of a suitable range of characterization techniques. Here, the authors present two such polymer core-shell nanoparticle systems, consisting of polytetrafluoroethylene cores coated with a range of thicknesses of either polymethylmethacrylate or polystyrene. By consideration of surface energy, it is shown that these particles are expected to possess distinctly differing coating structures, with the polystyrene coating being incomplete. A comprehensive characterization of these systems is demonstrated, using a selection of complementary techniques including scanning electron microscopy, scanning transmission electron microscopy, thermogravimetric analysis, dynamic light scattering, differential centrifugal sedimentation, and X-ray photoelectron spectroscopy. By combining the results provided by these techniques, it is possible to achieve superior characterization and understanding of the particle structure than could be obtained by considering results separately.
KW - Nanoparticles
KW - Core-shell
KW - XPS
KW - Size
KW - Thickness
KW - Damage
PY - 2020
DO - https://doi.org/10.1021/acs.jpcc.0c02161
VL - 124
IS - 20
SP - 11200
EP - 11211
PB - ACS
CY - Washington DC
AN - OPUS4-50899
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -