FG Struktur und Eigenschaften von Materialien

27 Items

Recent Submissions
The Neutron Imaging Instrument CONRAD—Post-Operational Review

Kardjilov, Nikolay ; Manke, Ingo ; Hilger, André ; Arlt, Tobias ; Bradbury, Robert ; Markötter, Henning ; Woracek, Robin ; Strobl, Markus ; Treimer, Wolfgang ; Banhart, John (2021-01-19)

The neutron imaging instrument CONRAD was operated as a part of the user program of the research reactor BER-II at Helmholtz-Zentrum Berlin (HZB) from 2005 to 2020. The instrument was designed to use the neutron flux from the cold source of the reactor, transported by a curved neutron guide. The pure cold neutron spectrum provided a great advantage in the use of different neutron optical compon...

Study on Cell Deformation of Low Porosity Aluminum Foams under Quasi‐Static Compression by X‐Ray Tomography

Wang, Ningzhen ; Chen, Xiang ; Maire, Eric ; Kamm, Paul H. ; Cheng, Ying ; Li, Yanxiang ; García-Moreno, Francisco (2020-06-03)

Understanding the correlation between cell deformation and initial cell structure during compression is important for improvement and development of effective applications of aluminum foams. Foams with porosities lower than 75% now get more attention because of more spherical cells and better mechanical performance. Herein, two low porosity aluminum foam samples are deformed by a compressive de...

Visualizing the morphological and compositional evolution of the interface of InLi-anode|thio-LISION electrolyte in an all-solid-state Li–S cell by in operando synchrotron X-ray tomography and energy dispersive diffraction

Sun, Fu ; Dong, Kang ; Osenberg, Markus ; Hilger, André ; Risse, Sebastian ; Lu, Yan ; Kamm, Paul H. ; Klaus, Manuela ; Markötter, Henning ; García-Moreno, Francisco ; Arlt, Tobias ; Manke, Ingo (2018-10-24)

Dynamic and direct visualization of interfacial evolution is helpful in gaining fundamental knowledge of all-solid-state-lithium battery working/degradation mechanisms and clarifying future research directions for constructing next-generation batteries. Herein, in situ and in operando synchrotron X-ray tomography and energy dispersive diffraction were simultaneously employed to record the morph...

Multi-stage ageing in an Al-Mg-Si alloy

Yang, Zi (2020)

Solute clustering and precipitation in Al-Mg-Si alloys have been extensively studied in the past decades oweing to an increasing importance of these alloys in industrial applications. However, many details are still not well understood, especially during multi-stage ageing. In this study, several aspects of multi-stage ageing in a commercial AA6014 alloy were systematically investigated, namely...

The Influence of Alloy Composition and Liquid Phase on Foaming of Al−Si−Mg Alloys

García-Moreno, Francisco ; Radtke, Laurenz Alexander ; Neu, Tillmann Robert ; Kamm, Paul Hans ; Klaus, Manuela ; Schlepütz, Christian Matthias ; Banhart, John (2020-01-28)

The foaming behaviour of aluminium alloys processed by the powder compaction technique depends crucially on the exact alloy composition. The AlSi8Mg4 alloy has been in use for a decade now, and it has been claimed that this composition lies in an “island of good foaming”. We investigated the reasons for this by systematically studying alloys around this composition by varying the Mg and Si cont...

Characterization of battery anode materials by X-ray and electron-based imaging techniques

Dong, Kang (2020)

To tackle the problem of increasing carbon dioxide emissions, Li batteries have been proposed as a promising storage medium of electricity harvested from renewable clean energy sources. In addition, Li batteries are the predominant power sources in cell phones, laptops and electric vehicles. However, state-of-art Li-ion batteries with an energy density below 300 Wh kg-1 cannot meet the ever-inc...

Electrochemical performance and structural changes of Na0.67Mn0.67Ni0.33O2 as cathode for sodium ion batteries

Zhang, Li (2019)

P2- and P3-type Na0.67Mn0.67Ni0.33O2 materials are potential cathodes for sodium ion batteries. P3-type Na0.67Mn0.67Ni0.33O2 demonstrates higher initial discharge capacity (233 mAh∙g-1) in the voltage range 1.5 - 4.5 V than P2-type Na0.67Mn0.67Ni0.33O2. However, the severe capacity fading in P3-type Na0.67Mn0.67Ni0.33O2 hinders its practical utilization as cathode for sodium ion batteries. Usin...

Influence of Sn addition on the ageing behavior of Al-Mg-Si alloys

Zhang, Xingpu (2019)

In this work, the ageing behavior of age hardenable Al-Mg-Si(Sn) alloys has been systematically studied by positron annihilation lifetime spectroscopy (PALS), hardness measurements, differential scanning dilatometry (DSC), electrical resistivity measurements and transmission electron microscopy (TEM). At room temperature, i.e. around 20 °C, vacancies, which can assist the diffusion of solute a...

Imaging with Polarized Neutrons

Kardjilov, Nikolay ; Hilger, André ; Manke, Ingo ; Strobl, Markus ; Banhart, John (2018-01-16)

Owing to their zero charge, neutrons are able to pass through thick layers of matter (typically several centimeters) while being sensitive to magnetic fields due to their intrinsic magnetic moment. Therefore, in addition to the conventional attenuation contrast image, the magnetic field inside and around a sample can be visualized by detecting changes of polarization in a transmitted beam. The ...

In Operando Neutron Radiography Analysis of a High-Temperature Polymer Electrolyte Fuel Cell Based on a Phosphoric Acid-Doped Polybenzimidazole Membrane Using the Hydrogen-Deuterium Contrast Method

Lin, Yu ; Arlt, Tobias ; Kardjilov, Nikolay ; Manke, Ingo ; Lehnert, Werner (2018-08-24)

In order to characterize high temperature polymer electrolyte fuel cells (HT-PEFCs) in operando, neutron radiography imaging, in combination with the deuterium contrast method, was used to analyze the hydrogen distribution and proton exchange processes in operando. These measurements were then combined with the electrochemical impedance spectroscopy measurements. The cell was operated under dif...

Influence of the Heating Rate on the Foaming Behavior of Various Aluminium Alloys

Neu, Tillmann Robert ; Pfretzschner, Beate ; García-Moreno, Francisco ; Banhart, John (2017-08-23)

Powders of metallurgically prepared precursors expand to a foam differently depending on how fast they are heated to their foaming temperature. The foaming behavior of four alloys was studied with heating rates varying from 0.1 K/s to 18 K/s. It was found that each alloy shows its own non-linear behavior of expansion values. Alloys not containing magnesium exhibit a maximum at intermediate heat...

Influence of Stoichiometry on the Two-Phase Flow Behavior of Proton Exchange Membrane Electrolyzers

Panchenko, Olha ; Giesenberg, Lennard ; Borgardt, Elena ; Zwaygardt, Walter ; Kardjilov, Nikolay ; Markötter, Henning ; Arlt, Tobias ; Manke, Ingo ; Müller, Martin ; Stolten, Detlef ; Lehnert, Werner (2019-01-23)

In order for electrolysis cells to operate optimally, mass transport must be improved. The key initial component for optimal operation is the current collector, which is also essential for mass transport. Water as an educt of the reaction must be evenly distributed by the current collector to the membrane electrode assembly. As products of the reaction, hydrogen and oxygen must also be directed...

Coalescence Avalanches in Liquid Aluminum Foams

Paeplow, Marlen ; García-Moreno, Francisco ; Meagher, Aaron Joseph ; Rack, Alexander ; Banhart, John (2017-08-04)

Coalescence is the rupture of a film between two adjacent bubbles in any type of liquid foam and has pronounced influence on the development of its macrostructure after solidification, mostly leading to larger pores and a wider size distribution. Foamable AlSi6Cu4 + 0.5 wt % TiH2 precursors made following the powder metallurgical route were foamed in a gas-tight X-ray transparent furnace under ...

Structural characterisation of A-site deficient Pr2-xNiO4+δ by X-ray diffraction, neutron diffraction and X-ray absorption spectroscopy

Ning, De (2019)

The crystal and electronic structures of Pr2-xNiO4+δ (x = 0 - 0.2), as potential materials for solid oxide fuel cell cathodes, are studied by X-ray diffraction, neutron diffraction and X-ray absorption spectroscopy. It turned out that A-site deficiency causes generation of vacancies at equatorial and apical oxygen sites but does not influence the interstitial oxygen content. In-situ X-ray diffr...

Einfluss der Kompaktierung auf das Schäumverhalten von pulvermetallurgisch hergestellten Metallhalbzeugen

Neu, Tillmann Robert (2019)

Die Herstellung von metallischen Schäumen ist von vielen Einflussfaktoren abhängig. Bei der pulvermetallurgischen Herstellung der Schaumhalbzeuge spielt neben anderen Gegebenheiten auch die Kompaktierung eine wichtige Rolle. Um diesen Einfluss besser zu verstehen, wurden in dieser Arbeit Halbzeuge mit verschiedenen konventionellen Kompaktierungsvarianten (uniaxiales Pressen, Strangpressen und W...

Schädigungscharakterisierung an Faser-Kunststoff-Verbunden im Schwingversuch mittels Röntgenrefraktionstopographie unter Berücksichtigung der Matrixeigenschaften

Müller, Alexander (2019)

In the present thesis different epoxy resin systems were characterized. Two systems with different fracture mechanical properties were selected for the production of equivalent GFRP and CFRP laminates with fiber orientations in 0/90° and ±45°. These laminates were examined for their damage onset and their damage evolution characteristics in tensile tests and fatigue tests with a stress ratio of...

An X-ray tomographic study of rechargeable Zn/MnO2 batteries

Osenberg, Markus ; Manke, Ingo ; Hilger, André ; Kardjilov, Nikolay ; Banhart, John (2018-08-21)

We present non-destructive and non-invasive in operando X-ray tomographic investigations of the charge and discharge behavior of rechargeable alkaline-manganese (RAM) batteries (Zn-MnO2 batteries). Changes in the three-dimensional structure of the zinc anode and the MnO2 cathode material after several charge/discharge cycles were analyzed. Battery discharge leads to a decrease in the zinc parti...

Microscopic aspects of ageing in Al-Mg-Si alloys

Madanat, Mazen Adel (2018)

Al-Mg-Si alloys with a low solute content (0.4 %Mg, 0.4 %Si) and higher contents (Mg+Si=1.4 %, all in wt.%) were solutionized, quenched and then either artificially aged (AA) at 180 °C or naturally pre-aged (NPA) for 2 weeks at room temperature and then reverse aged (RA) at 250 °C. Subsequently, positron annihilation lifetime spectroscopy was applied with the objective of obtaining information ...

Der Schäumprozess von Aluminiumlegierungen: Tomoskopische Untersuchung der Gasnukleation

Kamm, Paul Hans (2018)

Die Verbesserung der Struktur metallischer Schäume und damit ihrer Eigenschaften bedarf eines tieferen Verständnisses der während des Schäumens und der späteren Degradation ablaufenden Mechanismen. Um diesen dynamischen Prozess in seiner dreidimensionalen Komplexität und zeitlichen Veränderung zu erfassen wurde in dieser Arbeit das Verfahren der zeitaufgelösten Tomographie (Tomoskopie: Ein Kuns...

Suitability of various complex hydrides for foaming aluminum alloys

Kamm, Paul H. ; García-Moreno, Francisco ; Jiménez, Catalina ; Banhart, John (2013)

Some hydrides that could replace TiH2 as the hitherto most suitable blowing agent for foaming aluminum alloys were investigated. Hydrides taken from the group MBH4 (M = Li, Na, K) and LiAlH4 were selected since these have not been studied in the past although their decomposition characteristics appear to be suitable. Foamable precursors of alloy AlSi8Mg4 were manufactured by pressing blends of ...