TY - CONF A1 - Kamaraj, Abinaya A1 - Erning, Johann Wilhelm A1 - Reimann, S. A1 - Ahrens, A. T1 - Susceptibility of 304 stainless steel to crevice corrosion in electrochemically active fluids N2 - The susceptibility of AISI 304 stainless steel to crevice corrosion on the effect of contact with electrochemically active fluids was investigated using exposure and stepwise potentiostatic polarisation. Crevice materials made up of 304 SS and Polyether ether ketone (PEEK) forming two kinds of crevices including 304 SS-to-PEEK and 304 SS-to-304 SS were tested. T2 - Corrosion 2019 NACE CY - Nashville, TN, USA DA - 24.03.2019 KW - Desinfection KW - Crevice corrosion KW - ECA PY - 2019 AN - OPUS4-49284 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hodoroaba, Vasile-Dan A1 - Mansfeld, Ulrich A1 - Pellegrino, F. A1 - Maurino, V. A1 - Marguet, S. A1 - Testard, F. A1 - Tache, O. A1 - Bartczak, D. T1 - New reference material candidates for traceable size measurement of non-spherical nanoparticles N2 - New model nanoparticles with well-controlled shape were synthesized within the EMPIR project nPSize - Improved traceability chain of nanoparticle size measurements. Their systematic characterization takes place by the traceable methods scanning/transmission electron microscopy, atomic force microscopy and small angle X-ray scattering. Following reference nanoparticle candidates are under investigation with respect to their homogeneity and stability: titania nanoplatelets (10-15 nm x 50-100 nm), titania bipyramides (~60 nm x 40 nm), titania acicular particles (100 nm x 15-20 nm; aspect ratio 5.5/6), gold nanorods (~10 nm x 30 nm), and gold nanocubes (~55 nm x 55 nm x 55 nm). T2 - HyMET Workshop on optical surface analysis methods for nanostructured layers CY - Berlin, Germany DA - 10.10.2019 KW - Nanoparticles KW - Reference materials KW - Traceability KW - Particle size distribution PY - 2019 AN - OPUS4-49285 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Szymoniak, Paulina A1 - Qu, Xintong A1 - Schönhals, Andreas T1 - Competition of mobilization and Immobilization Effects in Epox-Based Nanocomposites N2 - Two epoxy-based nanocomposites with different nanofillers (layered double hydroxide and boehmite) were investigated employing temperature modulated DSC, flash DSC and broadband dielectric spectroscopy. Detailed investigation on the molecular mobility of the two systems showed the effect of the fillers on the structure of the bulk epoxy matrix and the interface formed at the polymer/particle interface T2 - FOR 2021: Acting principles of Nano-Scaled Matrix Additives for Composite Structures CY - Berlin, Germany DA - 11.10.2019 KW - TMDSC KW - Nanocomposites KW - Rigid amorphous fraction KW - Boehmite KW - BDS PY - 2019 AN - OPUS4-49287 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Spranger, Felix A1 - Schirdewahn, S. A1 - Kromm, Arne A1 - Merklein, M. A1 - Hilgenberg, Kai T1 - On the Influence of TiB2 , TiC and TiN Hard Particles on the Microstructure of Localized Laser Dispersed AISI D2 Tool Steel Surfaces N2 - The control of friction and wear is a major concern in many industrial applications. A promising method for a tailored surface modification is the so-called laser implantation technique. This method combines surface texturing and material optimization in one processing step by a localized dispersing of hard ceramic particles using pulsed laser radiation. Wear resistant, protruding micrometric features (implants) with defined geometry can be created in deterministic pattern where needed on highly stressed surfaces, i.e. on forming or cutting tools. However, in order to maintain the implants over the tool’s lifetime, a suitable selection of hard ceramic particles is a prerequisite. They must provide a defect-free Metal Matrix Composite with a high share of homogeneously distributed particles and especially a high implant hardness. In this study TiN, TiC and TiB2 hard particles were compared as implant materials for the first time. By a systematic variation of the pulse power and pulse duration, their dispersing behavior and influence on the material properties of AISI D2 tool steel was investigated. Although all powder materials had grain sizes smaller than 10 µm, it was possible to disperse them by pulsed laser radiation and to obtain defect-free protruding implants. The highest share of dispersed particles (~64 %) was observed for TiB2. By scanning electron microscopy and energy dispersive X-ray spectroscopy, it was also shown that a significant share of the pre-placed particles was dissolved by the laser beam and precipitated as nanometer sized particles within the matrix during solidification. These in-situ formed particles have a decisive influence on the material properties. While the TiN and TiC implants have shown maximum hardness values of 750 HV1 and 850 HV1, the TiB2 implants have shown the highest hardness values with more than 1600 HV1. By X-ray diffraction, it was possible to ascribe the lower hardness values of TiC and TiN implants to high amounts of retained austenite in the metal matrix. By implanting TiB2, the formation of retained austenite was successfully suppressed due to the in-situ formation of TiC particles, which was proven by electron backscatter diffraction. In conclusion, all the implant materials are basically suitable for laser implantation on AISI D2 tool steel. However, TiB2 has shown the most promising results. T2 - 38th International Congress on Applications of Lasers & Electro-Optics CY - Orlando, FL, USA DA - 07.10.2019 KW - Laser implantation KW - Surface texturing KW - AISI D2 KW - TiB2 PY - 2019 AN - OPUS4-49316 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Brunner-Schwer, C. A1 - Graf, B. A1 - Rethmeier, Michael T1 - Laser-Plasma-Hybrid-Cladding: Possibilities in the combination of arc and laser for deposition welding N2 - Plasma-Transferred-Arc (PTA) welding is a process that enables high deposition rates, but also causes increased thermal 9 load on the component. Laser based Direct Energy Deposition (DED) welding, on the other hand, achieves a high level of 10 precision and thus comparatively low deposition rates, which can lead to high processing costs. Combining laser and arc 11 energy aims to exploit the respective advantages of both technologies. 12 In this study, different possibilities of this process combination are presented using a PTA system and a 2 kW disk laser. 13 This includes the combination in a common process zone as a highspeed plasma laser cladding technology (HPLC), which 14 achieves process speeds of 10 m/min. Besides that it is being examined whether a pre-running plasma arc can be used to 15 coat difficult-to-weld rail steel with a carbon content of 0.8 % due to a preheating effect. Furthermore, a smoothing of the 16 coating by a plasma arc following the laser is investigated. T2 - LiM 2019 CY - Aachen, Germany DA - 25.06.2019 KW - Plasma-Transferred-Arc KW - Direct Energy Deposition KW - Highspeed plasma KW - Laser cladding KW - Deposition welding PY - 2019 AN - OPUS4-49247 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Meng, Xiangmeng A1 - Artinov, Antoni A1 - Bachmann, Marcel A1 - Rethmeier, Michael T1 - A theoretical study of influence of electromagnetic stirring on transport phenomena in wire feed laser beam welding N2 - The additional element from the filler wire in the laser beam welding is usually distributed inhomogeneously in the final weld due to the high solidification rate of weld pool. It has been found that the electromagnetic stirring produced by an external oscillating magnetic field can enhance the material mixing in the weld pool to achieve a more uniform element distribution. However, the magnetic field has a highly non-linear and multi-coupled interaction with the weld pool behavior, which makes the quantitative explanation of the physical mechanism difficult. In this study, the effect of electromagnetic stirring on the transport phenomena in the wire feed laser beam welding is investigated by a numerical modelling. A 3D transient multi-physical model considering the magnetohydrodynamics, heat transfer, fluid flow, keyhole dynamics and element transport is developed. The multiple reflections and the Fresnel absorption of the laser on the keyhole wall are calculated using the ray tracing method. The numerical results show that a Lorentz force produced by the oscillating magnetic field and its induced eddy current gives significant influence on the transport phenomena in the molten pool. The forward and downward flow is enhanced by the electromagnetic stirring, which homogenizes the distribution of the additional elements from a nickel-based filler wire in a steel weld pool. The numerical results show a good agreement with the high-speed images of the molten pool, the fusion line from the optical micrograph and the element distribution from the energy dispersive X-ray spectroscopy. This work provides a physical base for the electromagnetic-controlled laser beam welding and some guidance for the selection of electromagnetic parameters. T2 - ICALEO 2019 CY - Orlando, US DA - 07.10.2019 KW - Magnetohydrodynamics KW - Molten pool dynamics KW - Element transport KW - Laser beam welding PY - 2019 AN - OPUS4-49300 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bäßler, Ralph A1 - Le, Quynh Hoa A1 - Yevtushenko, Oleksandra A1 - Bettge, Dirk T1 - Corrosion Aspects for Materials to be Used in CC(U)S Applications N2 - This contribution provides current findings regarding materials susceptibility for carbon capture, utilization and storage (CCUS) applications. Basing on results gathered in 2 German long-term projects (COORAL and CLUSTER) suitable materials are introduced as well as dominating impurities of the CO2-stream and corrosion mechanisms. Investigations cover the whole CCUS process chain and provide material recommendations for certain parts. T2 - 1st International Conference on Corrosion Protection and Application CY - Chongqing, China DA - 09.09.2019 KW - Carbon KW - Capture KW - Storage KW - Utilization KW - CCS KW - CCU KW - CO2 KW - Corrosion PY - 2019 AN - OPUS4-49302 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weltschev, Margit A1 - Pötzsch, Sina T1 - Compatibility of polymeric sealing materials with biodiesel heating oil blends at different temperatures N2 - Biodiesel is subject to degradation processes like oil and grease. The oxidative degradation products of vegetable oil esters in biodiesel particularly lead to enhanced sedimentation in blended fuels. The polarity of biodiesel increases its solvency and facilitates permeation and extraction. Solvation, swelling and/or extraction lead to changes in the physical properties and chemical changes of polymeric materials. It also accelerates the degradation (hydrolysis and oxidation) of these materials with the loss of additives and stabilizers. The objective of this research was to determine the resistance of frequently used polymeric materials such as ACM, EPDM, FKM, FVMQ, CR, CSM, IIR, HNBR, NBR, PA, PE; POM, PUR, PVC and VMQ in biodiesel and heating oil with 10 %/20 % biodiesel (B10/B20) at 40°C and 70°C. Mass, tensile strength and breaking elongation of the test specimens were determined before and after the exposure for 84 days in the biodiesel heating oil blends. The visual examination of some elastomer test specimens clearly showed the great volume increase until break or partial dissolution. Shore hardness A and D were determined before and after exposure of the test specimens in the biofuels for 42 days. The elastomers CR, CSM, EPDM, IIR, NBR and VMQ were generally not resistant to biodiesel and B10 at 40°C and 70°C. FKM, ACM, HNBR, PA, PE, POM, and PVC showed high compatibility in B10/B20 at 40°C. A lower compatibility was determined for ACM in biodiesel. ACM and HNBR were not resistant in B20 at 70°C. T2 - Biofuels & Bioenergy CY - Rome, Italy DA - 14.10.2019 KW - Heating oil-Biodiesel-Blend KW - Compatibility evaluations KW - Tensile properties KW - Shore hardness PY - 2019 AN - OPUS4-49306 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bachmann, Marcel A1 - Artinov, Antoni A1 - Karkhin, V. A1 - Bakir, Nasim A1 - Meng, Xiangmeng A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael T1 - Lamé curves approximation for the assessment of the 3-D temperature distribution in keyhole mode welding processes N2 - A novel approach for the reconstruction of an equivalent volumetric heat source from a known weld pool shape is proposed. It is based on previously obtained weld pool geometries from a steady-state thermo-fluid dynamics simulation. Hereby the weld pool dimensions are obtained under consideration of the most crucial physical phenomena, such as phase transformations, thermo-capillary convection, natural convection and temperature-dependent material properties. The algorithm provides a time and calibration efficient way for the reproduction of the weld pool shape by local Lamé curves. By adjusting their parameters, the identification of the finite elements located within the weld pool is enabled. The heat input due to the equivalent heat source is assured by replacing the detected nodes’ temperature by the melting temperature. The model offers variable parameters making it flexible and adaptable for a wide range of workpiece thicknesses and materials and allows for the investigation of transient thermal effects, e.g. the cooling stage of the workpiece. The calculation times remain acceptably short especially when compared to a fully coupled process simulation. The computational results are in good agreement with performed complete-penetration laser beam welding experiments. T2 - International Congress on Applications of Lasers & Electro-Optics (ICALEO 2019) CY - Orlando, FL, USA DA - 07.10.2019 KW - Weld pool shape approximation KW - Keyhole mode laser beam welding KW - Numerical simulation KW - Superelliptic Lamé curves PY - 2019 AN - OPUS4-49309 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Erning, Johann Wilhelm A1 - Kamaraj, Abinaya T1 - Susceptibility of 304 stainless steel to crevice corrosion in electrochemically active fluids N2 - The crevice corrosion behaviour of stainless steel 304 L n ECA fluids is investigated. Results are described, rules for operation are suggested T2 - Ceocor-Tagung 2019 CY - Copenhagen, Denmark DA - 21.05.2019 KW - Desinfection KW - Crevice corrosion KW - ECA PY - 2019 AN - OPUS4-49280 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Artinov, Antoni A1 - Bachmann, Marcel A1 - Rethmeier, Michael T1 - A decoupling numerical approach for the study of hot cracking formation during high power keyhole mode welding of steel plates with a high sheet thickness N2 - The weld pool dynamics and shape play a fundamental role in keyhole mode welding. The presented work aims the experimental and numerical investigation of the influence of the weld pool characteristics on the formation of hot cracking. The experimental procedure allows recording the molten pool in the longitudinal section of a butt joint configuration of 15 mm thick structural steel and transparent quartz glass by using a high-speed video camera and two thermal imaging cameras. The observations show that the dimensions of the weld pool vary depending on the depth. The regions close to the surface form a teardrop-shaped weld pool. A bulge-region and its temporal evolution are observed approximately in the middle of the depth of the weld pool, where hot cracking appears. A numerical framework including models for the weld pool dynamics, global temperature field, transient stress state, crystal growth, diffusion and macro-segregation and subroutines for their one-way couplings is developed. The numerically obtained and experimentally observed results are in a good agreement. It is shown that the bulge-region leads to a delay in the solidification behavior, increased temporal tensile stresses and accumulation of impurities in the defect region and hence enhance the probability of hot cracking formation. T2 - Colloquium, Dept. Materials Science & Engineering, The Ohio State University CY - Columbus, Ohio, USA DA - 18.10.2019 KW - Keyhole mode welding KW - Weld pool shape KW - Bulge KW - Hot cracking PY - 2019 AN - OPUS4-49339 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Artinov, Antoni A1 - Bachmann, Marcel A1 - Rethmeier, Michael A1 - Karkhin, V. T1 - Mathematical modeling of the geometrical differences between the weld end crater and the steady-state weld pool N2 - The geometrical characteristics of the weld end crater are commonly used for the validation of numerical results in welding simulation. A semi-analytical model calculating the cooling stage of the welding process after the moving energy source is turned off has been developed. A solution for various combinations of heat sources and workpieces has been found. The theoretical limits for the heat transfer of the absorbed energy during cooling in a thin plate and a semi-infinite body were studied. It is shown that after turning off the energy source, an additional melting of the base material in longitudinal direction may occur. The developed technique is applied to complete-penetration keyhole laser beam welding of a 2 mm thick austenitic chromium-nickel 316L steel plate at a welding speed of 20 mm/s and a laser power of 2.3 kW. The results show a theoretical increase of the weld end crater length in comparison to the length of the steady-state weld pool of up to 19 %. A shift of the centre of the end crater, in which the solidification of the liquid metal ends, towards the tail of the end crater relative to the axis of the heat source at the time of its termination, was computed. The speed and the direction of crystallization of the molten material in the weld pool and the end crater were found to be different. A good agreement between the computational results and the welding experiments was achieved. T2 - ICALEO 2019 - The International Congress on Applications of Lasers & Electro-Optics CY - Orlando, FL, USA DA - 07.10.2019 KW - Keyhole mode welding KW - Weld pool shape KW - End-crater KW - Heat conduction PY - 2019 AN - OPUS4-49341 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute T1 - Advanced characterization of nanomaterials N2 - The rational synthesis and use of nanomaterials require the characterization of many different properties, ranging from particle size and size distribution over surface chemistry to more applicationrelevant features like optical, electrochemical, and magnetic properties. In the following, several methods for the characterization of functional groups on nanomaterials, like polymer and silica nanoparticles, semiconductor quantum dots, and lanthanide-based upconversion nanocrystals are presented. Additionally, procedures for the measurement of the key spectroscopic performance parameters of nanomaterials with linear and nonlinear photoluminescence, such as the photoluminescence quantum yield, are presented for the UV/vis/NIR/SWIR. T2 - Summerschool CY - Bad Honnef, Germany DA - 22.07.2019 KW - Quantum yield KW - Nanoparticle KW - Fluorescence KW - Quantum dot KW - NIR KW - SWIR KW - Quality assurance KW - Calibration PY - 2019 AN - OPUS4-48630 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sachse, René A1 - Kotil, L. A1 - Hodoroaba, Vasile-Dan A1 - Bernsmeier, Denis A1 - Kraehnert, R. A1 - Hertwig, Andreas T1 - Spectroscopic ellipsometric analysis of elemental composition and porosity of mesoporous iridium-titanium mixed oxide thin films for electrocatalytic splitting of water N2 - Porous materials play an important role in several fields of technology, especially for energy applications like photovoltaics, electrolysis or batteries. The activity of porous films is affected by properties like porosity, film thickness, chemical composition of the material as well as the crystallinity of the framework. The complex morphology of such porous films constitutes a challenge for modern analytical techniques and requires approaches employing the combination/complementation of data of different analytical methods. In this contribution we characterize thin mesoporous iridium-titanium mixed oxide film properties by spectroscopic ellipsometry (SE). Mesoporous iridium oxide - titanium oxide (IrOx-TiOx) films were prepared via dip-coating of a solution containing a triblock-copolymer as structure-directing agent, an iridium precursor as well as a titanium precursor in ethanol. Deposited films with different amounts of iridium (0 wt%Ir to 100 wt%Ir) were synthesized and calcined in air. The thin films were analyzed with SE using the Bruggeman effective medium approximation (BEMA) for modelling. The results were compared with electron probe microanalysis (EPMA) as part of a combined SEM/EDS/STRATAGem Analysis. T2 - 8th International conference on spectroscopic ellipsometry (ICSE-8) CY - Barcelona, Spain DA - 26.05.2019 KW - Mesoporous iridium-titanium mixed oxides KW - Thin films KW - Spectroscopic ellipsometry KW - Oxygen evolution reaction KW - EPMA KW - Ellipsometric porosimetry PY - 2019 AN - OPUS4-48387 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Koerdt, Andrea A1 - An, Biwen Annie A1 - Kleinbub, Sherin A1 - Herrmann, Annett T1 - Investigation of methanogen-induced microbiologically influenced corrosion (Mi-MIC) using simulated marine environments under flowing conditions N2 - Microbiologically influenced corrosion (MIC) of iron is usually attributed to sulfate-reducing microorganisms (SRM) in oil and gas facilities. SRM act upon the metal by the re-activeness of hydrogen sulfide (HS-), and by withdrawal of the available electrons in electrical contact with the metal (EMIC). Methanogenic archaea (MA) can also cause MIC (Mi-MIC). Several MAs were identified to be corrosive by using elemental iron as the sole electron donor for methanogenesis, including Methanobacterium­-affliated IM1 and Methanococcus maripaludis Mic1c10. Currently, low corrosion rates were reported for MA, possibly due to the formation of siderite (4Fe + 5HCO3- + 5H+ ® 4FeCO3 + CH4 + 3H2O). Since MA do not produce HS-, withdrawal of electrons may be their main corrosive mechanism; however, mechanistic details and kinetics of the overall process are poorly understood. To investigate the corrosion potential of MA, we studied the EMIC methanogenic strains (IM1 and Mic1c10) individually or part of a syntrophic co-culture with SRM. Corrosion studies were conducted using an in-house developed flow-through system to simulate fluctuating environmental conditions. Results indicate that the rates of iron corrosion by MA (up to 0.4 mm/yr) are higher to that caused by the marine SRM Desulfovibrio alaskensis (0.15 mm/yr) and the co-culture (0.1 mm/yr). Scanning electron microscopy (SEM) images of the metal incubated with MA showed severe pitting corrosion. Genomic analysis of the EMIC MA was conducted to provide an insight on the possible cellular mechanisms that could be involved. Furthermore, low concentrations of MA-targeting biocides will be applied to EMIC MA in static and flow conditions to gain insights for possible mitigation strategies. Such knowledge and deeper understanding also from an electrokinetic point of view may not only provide further models in microbial electrophysiology, but also contribute to mitigation strategies in MIC. T2 - 7th International Symposium on Applied Microbiology and Molecular Biology in Oil Systems CY - Halifax, Canada DA - 18.06.2019 KW - MIC KW - Microbiologically influenced corrosion KW - Methanogens KW - SRB KW - Corrosion KW - Metalls PY - 2019 AN - OPUS4-48392 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bruno, Giovanni T1 - Engineering applications of neutrons at the ILL: retrospective, present, and future N2 - In this talk, the evolution of the demand for engineering applications of neutrons at the ILL in the last 10 years is presented. It is shown that small angle neutron scattering and diffraction are highly demanded by the materials science community. Further development in the field is foreseen, with the use of in-situ (furnace, tension/compression rig, humidity cells, etc.) techniques to associate to the neutron techniques. T2 - ILL 100th Scientific Council CY - Grenoble, France DA - 09.04.2019 KW - Neutron Diffraction KW - Residual Stress KW - Small Angle Neutron Scattering KW - Engineering applications KW - Institut Laue Langevin PY - 2019 AN - OPUS4-48396 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Evsevleev, Sergei A1 - Paciornik, Sidnei A1 - Gollwitzer, Christian A1 - Bruno, Giovanni T1 - Application of deep learning to the segmentation of synchrotron X-ray tomography data of multiphase metal matrix composites N2 - The 3D microstructure of an Al alloy matrix composite with two ceramic reinforcements was investigated by synchrotron X-ray tomography. A deep learning algorithm was used for the segmentation of four different phases. We show that convolutional networks with the U-Net architecture are able to solve complex segmentation tasks with small amount of training data. T2 - International Conference on Tomography of Materials & Structures CY - Cairns, Australia DA - 22.07.2019 KW - Synchrotron X-ray tomography KW - Deep learning KW - Segmentation KW - Metal matrix composite PY - 2019 AN - OPUS4-48606 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rabe, Torsten A1 - Schulz, Bärbel A1 - Paulick, C. T1 - Development of ceramic helical springs for sensor applications N2 - At high temperatures and in harsh environments ceramic springs are often superior to metallic ones and allow for innovative solutions. A further application was proposed by using ceramic springs as capacitive force sensor. Lower and upper coil surfaces are coated by electrically conducting layers. Deformation of such spring results in a change of capacity. Sensor application calls for helical springs with rectangular cross-section, a linear stress-strain characteristic over entire deformation range and low manufacturing tolerances relating to inner and outer diameter, coil cross section and spring pitch. Furthermore, complex spring design with integrated connecting elements has to be realized. Alumina, zirconia (Y-TZP) and silicon nitride springs were produced by hard machining starting from sintered hollow cylinders. After external and internal cylindrical grinding the hollow cylinders were filled with hard wax, followed by multi-stage cutting of spring coils with custom-made cutting discs. Finally, hard wax was removed by melting and burnout. Best surface and edge qualities of springs were reached using Y-TZP material and hot isostatic pressed alumina. Y-TZP springs produced with material-specifically selected cutting discs and optimized process parameters show sharp coil edges without spallings and mean roughness values of inner surfaces < 0.2 μm. Manufacturing tolerances of spring diameters, spring pitch, height and width of coil cross section are in the range of ± 10 microns. Good reproducibility of spring geometry by optimized hard machining technology allows for production of Y-TZP springs with spring constants differing less than ± 1 % within a series. According to DIN 2090 spring constant for rectangular coil cross section is proportional to the square of height and width of coil cross section and indirectly proportional to number of active coils and to the cube of the mean spring diameter. Hence, spring constants can be tailored over a range of many orders of magnitude by changing the spring dimensions. Good agreement was reached between calculated target spring constants and measured values on produced springs. Alumina and zirconia springs were characterized relating to deformation behavior under dynamic compression load with various deformation speeds and under static tensile loads over long periods of time. Contrary to alumina springs, a non-linear stress-strain behavior of TZP springs was proved in both test series. It is supposed, that pseudoelasticity caused by stress-induced transformation of tetragonal to monoclinic phase is responsible for this special feature of TZP springs. Therefore, TZP material cannot be used for capacitive spring sensors. T2 - European Ceramic Society Conference (ECerS) CY - Torino, Italy DA - 16.06.2019 KW - Ceramic spring KW - Sensor KW - Spring constant KW - Failure test KW - Microstructure PY - 2019 AN - OPUS4-48610 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lin, Xuebao A1 - Tan, Yi A1 - Wachtendorf, Volker A1 - Klack, Patrick A1 - Schoch, R. A1 - Lang, M. A1 - Schartel, Bernhard T1 - Weathering Resistance of Halogen-free Flame Retardance in E&E Polymeric Materials N2 - Nowadays, various polymeric materials are used in E&E applications with sufficient flame retardance by adding rather different flame retardants. It doesn’t matter whether cables are used outdoor or are installed indoor as building products, the weathering exposures such as UV radiation, humidity and variation in temperature occur and influence the flame-retardant property. Recently, the lifetime of the flame retardance itself becomes an increasingly important factor. In this work, several devices were used to perform accelerated artificial ageing simulating different environment exposures. The comprehensive and global understanding of the durability of flame retardance in dependence on the weathering or ageing conditions is still a matter of discussion. Therefore, the weathering resistance of various halogen-free fire-retarded polymers was investigated in this work. Polymeric systems with different kinds of fire retardants were chosen, including various fire retardant mechanisms. Ethylene Vinyl Acetate (EVA) blends with high amounts of inorganic flame retardant such as aluminum hydroxide (ATH), boehmite and synergists, which mainly dilutes the polymer resin work as heat sink and cooling agent, and enhance residue formation was examined. Thermoplastic Polyurethane (TPU) was modified with melamine cyanurate (MC), which mainly acts by changed melt flow and dripping behavior as well as fuel dilution. Additionally, aluminum diethylphosphinate and boehmite are induced as assistant flame retardant. Furthermore, glass fiber reinforced Polyamide 66 (PA) was investigated containing different kinds of aluminum diethylphosphinate based flame retardant mixtures, which acts by flame inhibition and additional char formation. The degradation of the surface was analyzed after the different weathering conditions. Most of the specimens exhibited an intensive material degradation at the top surface accompanied by a distinct discoloration, e.g. getting darker or showing yellowing. The weathering of the EVA samples lead to numerous cracks (already) after 4000 h. The corresponding changes in the chemical structure was investigated by ATR FT-IR for all materials. The flammability was investigated by cone calorimeter, UL-94 burning chamber, and oxygen index (LOI) using plate and bar specimens. The flame retardance of most of the materials studied degrades only slightly or were rather stable for the investigated exposure times. Interestingly, also some opposite results were found. EVA modified by different inorganic flame retardants such as ATH achieved higher LOI after exposing in the humidity chamber and the accelerated oxidation under water in the autoclaves. It is suggested that the particle size of ATH and boehmite plays an important role, when these flame retardants agglomerate at the surface during accelerated weathering. Both materials, EVA and TPU, were also investigated as cable jackets. While EVA modified with inorganic flame retardants exhibits low-smoke and non-dripping fire behavior, TPU flame-retarded with MC yields cables with pronounced melt-dripping. Cone calorimeter tests were carried out using cable rafts of the size of 100 mm * 100 mm as well as our self-made cable module test, which simulates the vertical full-scale test of a bundle of cables at the bench-scale. Both methods were used to investigate the weathering resistance of the flame retardance in cables. The results of the cable module test for the flame-retarded EVA cables were only slightly affected even when a long time hydrothermal ageing was carried out. This is because of inorganic residue which just delays the fire growth but does not extinguish. However, for the flame-retarded TPU cable jackets, the cable module test exhibited an accelerated fire spread and a melt-dripping behavior which was promoted by weathering exposure. T2 - FRPM 2019, 17th European Meeting on Fire Retardant Polymeric Materials CY - Turku, Finland DA - 26.06.2019 KW - Cable KW - Flame retardant KW - Weathering resistance KW - Durability KW - ethylene vinyl acetate KW - Thermoplastic polyurethane KW - Flammability PY - 2019 AN - OPUS4-48553 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hodoroaba, Vasile-Dan T1 - High-Quality Experimental Data in Electron Microscopy and Microanalysis – What can, and should we jointly do? N2 - There are different ways how to prove the quality of the results obtained by electron microscopy and related microanalysis techniques, e.g. use of validated standard operation procedures, participation in proficiency testing exercises, use of certified reference materials, etc. International standards are able to provide requirements, specifications, guidelines or characteristics of methods, instruments or samples with the final goal that these can be used consistently in accredited laboratories. In the field of electron microscopy and microbeam analysis standardization and metrology are terms which are encountered rather seldom at major conferences and scientific publications. Nevertheless, spectra formats like EMSA/MSA for spectral-data exchange or tagged image file format (TIFF) for SEM, guidelines for performing quality assurance procedures or for the specification of X-ray spectrometers as well as of certified reference materials (CRMs) in EPMA, or measurement of average grain size by electron backscatter diffraction (EBSD), or guidelines for calibrating image magnification in SEM or TEM are ISO standards already published and used successfully by a large part of the electron microscopy and microbeam analysis community. A main and continuous task of ISO/TC 202 and its subcommittees is to identify and evaluate feasible projects/proposals needed to be developed into new international standards, particularly in respect to recent but established technology, such the silicon drift detector (SDD) EDS one. Another international platform in the frame of which pre-standardization work can be organized is VAMAS (Versailles Project on Advanced Materials and Standards). International collaborative projects involving aim at providing the technical basis for harmonized measurements, testing, specifications, and standards to be further developed at ISO level. One key point of VAMAS activities is constituted by inter-laboratory comparisons for high-quality data. In the field of microbeam analysis, the technical working area (TWA) 37 Quantitative Microstructural Analysis deals with corresponding projects. Good ideas, e.g. on analysis of low-Z materials/elements and at low energies are particularly encouraged by directly contacting the author. Support and already available guidance will be supplied. T2 - Microscopy & Microanalysis 2019 CY - Portland, OR, USA DA - 03.08.2019 KW - Pre-standardisation KW - Inter-laboratory comparison KW - VAMAS KW - ISO KW - Electron microscopy KW - Microanalysis PY - 2019 AN - OPUS4-48672 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kromm, Arne A1 - Lausch, T. A1 - Schröpfer, Dirk A1 - Rhode, Michael A1 - Kannengießer, Thomas T1 - Influence of welding stresses on relaxation cracking during heat treatment of a creep-resistant 13CrMoV steel N2 - Over the past years economic and environmental considerations have led to a markedly increased demand for efficiency and flexibility in petrochemical plants. The operational temperatures and pressures required today can only be achieved by using new creep-resistant grades of steel. The modified 13CrMoV9-10 vanadium steel shows a good resistance against creep and compressed hydrogen and has been in use for the construction of petrochemical reactors since the mid-1990s. Nevertheless, processing of this type of steel requires extreme care during the welding procedure. This is due to its low toughness and high strength in the welded state when not post weld heat treated combined with increased susceptibility to cracking during stress relaxation. Previous research into crack formation in creep-resistant steels has largely focused on thermal and metallurgical factors; however, little knowledge has been gathered regarding the influence of the welding procedure on crack formation during post weld heat treatment considering real-life manufacturing conditions. The influence of heat control on the mechanical properties has been investigated by simulating the welding and subsequent post weld heat treatment operations during the construction of petrochemical reactors using a special 3-D testing facility on the laboratory scale. This work is subdivided in two parts. In part I of this study the stresses resulting from preheating, welding, dehydrogenation heat treatment and the final post weld heat treatment were analyzed during experiments under varied heat control. In all experiments stress relief cracks formed during post weld heat treatment could be observed. The total crack lengths correlated with the welding induced stresses. Part II of this work is dedicated to the characterization of the cracks and the microstructure. The application of a special acoustic emission analysis indicated that the cracks formed in a temperature range between 300 °C and 500 °C during the post weld heat treatment. In comparison to small scale specimens welded without additional shrinkage restraint, the toughness of the restrained welds was significantly decreased. SEM and TEM analyses of all samples revealed accelerated aging due to early precipitation of special carbides during post weld heat treatment under component relevant restraint. T2 - IIW Annual Assembly CY - Bratislava, Slovakia DA - 08.07.2019 KW - Welding KW - Creep-resistant steel KW - Post weld heat treatment KW - Stress relief cracking PY - 2019 AN - OPUS4-48580 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Theiler, Géraldine A1 - Gradt, Thomas T1 - High performance polymer materials for tribological applications in hydrogen and methane N2 - The development of hydrogen technologies is a key strategy to reduce greenhouse gas emission worldwide. Power-to-Gas is a challenging solution, in which hydrogen and methane can be used in mobility, industry, heat supply and electricity generation applications. This presentation deals with the tribological behaviour of polymer materials in hydrogen and methane, both in gas and in liquefied form. T2 - ECOTRIB 2019 CY - Vienna, Austria DA - 12.06.2019 KW - Sliding wear KW - Polymer materials KW - Hydrogen methane PY - 2019 AN - OPUS4-48250 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Léonard, Fabien T1 - Good practice guide on the correct choice of characterisation technique based on level of accuracy and type of measurement N2 - The characterisation of AM structures is an important aspect of the AM process, required in order to: 1. optimise the AM printing process 2. assess the quality of produced parts A wide range of characterisation techniques are available, and the selection can be complex, based on multiple factors. One output from the MetAMMi project is a good practice guide on the correct choice of characterisation technique. T2 - Workshop on additive manufacturing CY - Berlin, Germany DA - 13.05.2019 KW - X-ray computed tomography KW - Mechanical properties KW - Microstructural analysis KW - Defect detection PY - 2019 AN - OPUS4-48262 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Emmerling, Franziska T1 - New insights in cocrystal formations: in situ investigations of mechanochemical syntheses N2 - Mechanochemistry is increasingly used for synthesizing soft matter materials including metal organic compounds and cocrystals. The ever-increasing interest in this method is contrasted by a limited mechanistic understanding of the mechanochemical reactivity and selectivity. Time-resolved in situ investigations of milling reactions provide direct insights in the underlying mechanisms. We introduced a setup enabling in situ investigation of mechanochemical reactions using synchrotron XRD combined with Raman spectroscopy. The specific combination allows to study milling processes comprehensively on the level of the molecular and crystalline structure and thus obtaining reliable data for mechanistic studies. We discuss our recent results investigating the formation of (polymorphic) cocrystals. First investigations of a mechanochemical synthesis under controlled temperature which allow determining the activation barrier are presented.6 Furthermore, X-ray diffraction and in situ Raman spectroscopy coupled with thermography revealed a low temperature increase during milling reactions due to the mechanical impact and clear temperature increases as a result of the reaction heat. Our results indicate that in situ investigation of milling reactions offer a new approach to tune and optimize mechanochemically synthesized compounds. T2 - CSEC Seminar University of Edinburgh CY - Edinburgh, Scotland DA - 16.05.2019 KW - Mechanochemistry KW - Acoustic levitation KW - In situ PY - 2019 AN - OPUS4-48098 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Reinsch, Stefan A1 - Tielemann, Christopher A1 - Busch, R. A1 - Patzig, C. A1 - Müller, Ralf A1 - Höche, T. T1 - Oriented surface crystallization in 18BaO·22CaO·60SiO2 and MgO·CaO·2SiO2 glasses N2 - Up to now, oriented surface crystallization phenomena are discussed controversially, and related studies are restricted to few glasses. The vast majority of previous work does not consider possible effects of surface preparation and surrounding atmosphere. Moreover, very few observations of surface crystal orientation were made on separately grown crystals. The aim of our project is to advance the basic understanding of oriented surface crystallization, e.g. whether preferred orientation of surface crystals results from oriented nucleation or reorientation mechanisms during early crystal growth. In both cases, crystal orientation may reflect the orientation of the glass surface or that of anisotropic active surface nucleation sites. Therefore, we focus on orientation of surface crystals separately growing under controlled conditions. First results on diopside (MgCaSi2O6) and walstromite (BaCa2Si3O9) crystals growing from 18BaO·22CaO·60SiO2 and MgO·CaO·2SiO2 glass surfaces, respectively, indicate that different orientation mechanisms may occur. Neighbored walstromite crystals were found to gradually reorient themselves when they are going to impinge each other during stepwise isothermal treatments (log η = 4,5 Pa*s) of polished glass samples. Nevertheless, no preferred crystal orientation was evident for separate crystals. For diopside crystals growing from polished glass surfaces (1 μm diamond lapping foil), strong preferred orientation was observed for 3.5 to 85 min annealing at 850 °C. Electron Backscatter Diffraction (EBSD) studies showed that the c-axis of surface crystals is oriented parallel to the glass surface and that separated diopside crystals as small as 600 nm are already oriented. Studies on glass surfaces, polished with diamond lapping foils starting from 16 μm down to 1 μm grain, revealed that crystal orientation may scatter arround this preferential orientation and that this scatter progressively decreases with decreasing polishing grain size. T2 - 93rd Annual Meeting of the German Society of Glass Technology (DGG) in conjunction with the French Union for Science and Glass Technology (USTV) Annual Meeting CY - Nuremberg, Germany DA - 13.05.2019 KW - Surface crystallization KW - Orientation KW - Glass KW - Diopside PY - 2019 AN - OPUS4-48198 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn T1 - A survey of surface functionalization through laser-induced periodic surface structures N2 - Laser-induced periodic surface structures (LIPSS, ripples) are a universal phenomenon that can be observed on almost any material after the irradiation by linearly polarized laser beams, particularly when using ultrashort laser pulses with durations in the femtosecond to picosecond range. During the past few years significantly increasing research activities have been reported in the field of LIPSS, since their generation in a single-step process provides a simple way of nanostructuring and surface functionalization towards the control of optical, mechanical, biological, or chemical surface properties. In this contribution the mechanisms of formation and current applications of LIPSS are reviewed, including the colorization of technical surfaces, the control of surface wetting properties, the mimicry of the natural texture of animal integuments, the tailoring of surface colonization by bacterial biofilms, the advancement of medical pacemakers, and the improvement of the tribological performance of nanostructured metal surfaces. T2 - Seminar, ALPhANOV - Centre Technologique Optique et Lasers CY - Talence, France DA - 07.06.2019 KW - Laser-induced periodic surface structures, LIPSS KW - Surface functionalization KW - Applications KW - Femtosecond laser PY - 2019 AN - OPUS4-48199 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ehlers, Henrik A1 - Pelkner, Matthias T1 - Electromagnetic testing for additive manufacturing N2 - This talk presents a new application for high-spatial resolution eddy current testing (ET) with magneto resistive (MR) sensor arrays. With rising popularity and availability of additive manufacturing (AM), companies mainly in the aerospace sector, set high requirements on quality control of AM parts, especially produced with selective laser melting (SLM). Since it was shown that those parts are prawn to flaws like pores or cracks, every part needs to be tested. Therefore, NDT Methods, like ET, could help to characterize SLM parts. Research on ET has shown, that offline ET with high spatial resolution MR sensor arrays is possible and that flaws as small as 50 µm could be detected while significantly reducing testing time. In this talk a first approach on automated online ET method for testing SLM parts is proposed. An approach with hundreds of MR sensor is made to maintain spatial resolution and short testing times. Classic signal conditioning methods are used to reduce cost and complexity while maintaining high testing bandwidths. The proposed idea enables further research on automated generation of testing reports, process control or automated flaw curing. T2 - ICWAM 2019 CY - Metz, France DA - 05.06.2019 KW - GMR KW - Eddy Current KW - LBM KW - SLM KW - LPBF KW - Additive Manufacturing PY - 2019 AN - OPUS4-48201 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana T1 - Characterization of co (polyamide)s N2 - Characterization problems of technically relevant copolyamides applying size exclusion chromatography, interaction chromatography and their combination with MALDI-TOF-MS will be discussed. T2 - 23. Kolloquium Massenspektrometrie und synthetische Polymere CY - Berlin, Germany DA - 14.05.2019 KW - LCCC KW - Mass spectrometry of polymers KW - SEC KW - LC / MALDI-TOF-MS coupling PY - 2019 AN - OPUS4-48221 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias A1 - Grelle, Tobias A1 - Kömmling, Anja A1 - Wolff, Dietmar A1 - Völzke, Holger T1 - Long-term evaluation of sealing systems for radioactive waste packages N2 - The investigation of the long-term performance of sealing systems employed in containers for radioactive waste and spent nuclear fuel is one research focus area for division 3.4 “Safety of Storage Containers” at the Bundesanstalt für Materialforschung und -prüfung (BAM). Our investigations comprise investigations on metallic and elastomeric seals and covers experimental investigations to get a database on the component/material behaviour, work on analytical descriptions and numerical analysis. Our aim is to understand the long-term behaviour of the sealing systems for evaluation of their performance during possible extended interim storage and subsequent transportation. T2 - 3rd Workshop on Safety of Extended Dry Storage of Spent Nuclear Fuel CY - Garching, Germany DA - 05.06.2019 KW - Seal performance KW - Rubber seal KW - Metallic seal KW - Ageing PY - 2019 AN - OPUS4-48224 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lohrer, Christian T1 - Report from the Forum of Notified Bodies for Pyrotechnic Articles N2 - Aktuelle Themen aus dem Forum der benannten Stellen für Pyrotechnik bei der EU-KOM werden vorgestellt, unter anderem zu den Themen Kennzeichnung, Round Robin Test, Konformitätserklärungen, Sicherheitsabstände N2 - Current topics and challenges in the forum of notified bodies for pyrotechnics at the EU-COM will be presented: labelling, round robin tests, declarations of conformity, safety distances. T2 - Meeting of the group of experts on pyrotechnic articles CY - Brussels, Belgium DA - 17.06.2019 KW - Konformitätserklärung KW - Pyrotechnik KW - Kennzeichnung KW - RRT KW - Round robin tests KW - Labelling KW - Declarations of conformity KW - Pyrotechnics PY - 2019 AN - OPUS4-48227 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hodoroaba, Vasile-Dan T1 - Quantitative microstructural analysis - VAMAS/TWA 37 N2 - The 44th Meeting of the Versailles Project on Advanced Materials and Standards (VAMAS) Steering Committee has just taken place at NIST in Boulder (CO, USA). BAM participates with significant contributions in Technical Working Areas on nanoparticle and surface chemistry characterization, but also has positioned itself to new global material challenges and trends in the developement of advanced materials and their characterization, such as thermal properties, self-healing materials, and micro- and nanoplastic. T2 - Annual Meeting of the Versailles Project on Advanced Materials and Standards (VAMAS) Steering Committee CY - Boulder, CO, USA DA - 22.05.2019 KW - VAMAS KW - Nanoparticles KW - Microbeam analysis KW - Advanced materials PY - 2019 AN - OPUS4-48184 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pauw, Brian Richard T1 - Everything SAXS N2 - Introduction keynote for the "Small Angle Scattering Training School 2019", introducing a wide range of aspects around small-angle scattering. T2 - Small Angle Scattering Training School 2019 CY - Diamond Light Source, Didcot, UK DA - 04.06.2019 KW - X-ray scattering KW - Nanostructure KW - Introduction KW - Practical aspects PY - 2019 AN - OPUS4-48191 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pauw, Brian Richard A1 - Breßler, Ingo T1 - McSAS for SAS analysis: Usage, benefits, and potential pitfalls N2 - Introducing McSAS, the analytical tool (software) we developed for extracting form-free size distributions from X-ray scattering patterns. T2 - Small Angle Scattering Training School 2019 CY - Diamond Light Source, Didcot, UK DA - 04.06.2019 KW - X-ray scattering KW - SAXS KW - Software KW - Monte Carlo KW - Nanocharacterisation KW - Nanostructure PY - 2019 AN - OPUS4-48192 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pauw, Brian Richard A1 - Smales, Glen Jacob T1 - Experimenting on MAUS N2 - Initial results, findings and experience after 1.5 years of using the Multi-scale Analyser for Ultrafine Structures (MAUS), a bespoke wide-range SAXS instrument for the nanostructure quantification of demanding materials science samples. T2 - S4SAS Conference 2019 CY - Diamond Light Source, Didcot, UK DA - 06.06.2019 KW - X-ray scattering KW - SAXS KW - Nanostructure quantification KW - Nanocharacterisation PY - 2019 AN - OPUS4-48193 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Reinsch, Stefan A1 - Müller, Ralf A1 - Agea-Blanco, Boris A1 - Blaeß, Carsten A1 - Waurischk, Tina T1 - Sintering and foaming of silicate glass powders N2 - Glass powders are promising candidates for manufacturing a broad diversity of sintered materials like sintered glass-ceramics, glass matrix composites, glass bonded ceramics or pastes. Powder processing, however, can substantially affect sinterability, e.g. by promoting surface crystallization. On the other hand, densification can be hindered by gas bubble formation for slow crystallizing glass powders. Against this background, we studied sintering and foaming of silicate glass powders with different crystallization tendency for wet milling and dry milling in air, Ar, N2, and CO2 by means of heating microscopy, DTA, Vacuum Hot Extraction (VHE), SEM, IR spectroscopy, XPS, and ToF-SIMS. In any case, foaming activity increased significantly with progressive milling. For moderately milled glass powders, subsequent storage in air could also promote foaming. Contrarily, foaming could be substantially reduced by milling in water and 10 wt% HCl. Although all powder compacts were uniaxially pressed and sintered in air, foaming was significantly affected by different milling atmosphere and was found most pronounced for milling in CO2 atmosphere. Conformingly, VHE studies revealed that foaming is mainly driven by carbonaceous species, even for powders milled in other gases. Current results of this study thus indicate that foaming is caused by carbonaceous species trapped on the glass powder surface. T2 - IMAPS/ACerS 15th International Conference and Exhibition on Ceramic Interconnect and Ceramic Microsystems Technologies (CICMT 2019) CY - Shanghai, China DA - 16.04.2019 KW - Glass powder KW - Sintering KW - Foaming PY - 2019 AN - OPUS4-48196 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Askar, Enis A1 - Schröder, Volkmar T1 - The influence of strong ignition sources on the explosion and decomposition limits of gases N2 - Explosion and decomposition limits of flammable and chemically unstable gases were determined experimentally in a dosed autoclave with varying ignition energy up to 1000 J. The ignition source was a lightning arc caused by an exploding wire igniter as described in EN 1839 B .. In case of methane only the upper explosion limit was influenced significantly by the ignition energy, whereas the lower explosion limit was constant. In case of R32 however. it was the lower explosion limit that was influenced significantly by the ignition energy and not the upper explosion limit. A particularly strong dependency from the ignition energy was found for the decomposition limits of the chemically unstable gases in nitrogen. T2 - 16th International Symposium on Loss Prevention and Safety Promotion in the Process Industries CY - Delft, The Netherlands DA - 16.06.2019 KW - Explosionsgrenzen KW - Zündenergie KW - Chemisch instabile Gase KW - Kältemittel KW - Zündquellen PY - 2019 AN - OPUS4-48993 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Malow, Marcus A1 - Knorr, Annett A1 - Jungnickel, Ralf T1 - Different methods for the determination of calcium peroxide N2 - The CaO2 Content ist analyzed using different titration methods. The results and the methods are compared. CaO2 is a reference material in the UN Test method O.3. T2 - EOS IGUS Meeting CY - Brussels, Belgium DA - 21.05.2019 KW - Dangerous Goods KW - UN-Test O.3 KW - Calcium peroxid KW - Content of calcium peroxide PY - 2019 AN - OPUS4-49001 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weltschev, Margit A1 - Pötzsch, Sina A1 - Bäßler, Ralph T1 - Compatibility of polymers with heating oil with 20 % biodiesel at different temperatures under static and compressed conditions N2 - Biodiesel is viewed as a major source of energy. In areas such as the European Union, where 80 % of the oil-based fuel is imported, there is also the desire to reduce dependence on external oil supplies. Materials compatibility is a major concern whenever the fuel composition is changed. The question arises of whether polymeric materials are resistant to heating oil with 20 % biodiesel (B20) in comparison to pure heating oil. The polarity of biodiesel increases its solvency and facilitates permeation and extraction. Solvation, swelling and/or extraction lead to changes in the physical properties. Extraction alters the fuel chemistry. These chemical changes could also accelerate the degradation (hydrolysis and oxidation) of the polymeric material with the loss of additives and stabilizers. The objective of this research was to determine the resistance of frequently used materials for components in middle distillate facilities such as ACM, FKM, HNBR, PA, PE, POM, PUR and PVC in heating oil and heating oil blend B20 for 84 days at 40 °C, and FKM, HNBR, PA, POM, PUR and PVC at 70 °C. Mass, tensile strength, breaking elongation and Shore hardness A (D) of the test specimens were determined before and after exposure for 84 (42) days in the test fuels under static conditions. For the investigations under compressed conditions, the mass and the compression set of FKM test specimens were determined before and after exposure for 3, 7, 14, 28, 56 and 90 days in B20 at 40 °C and 70 °C according to ISO 815-1 “Rubber, vul-canized or thermoplastic - determination of compression set – Part 1: At ambient or elevated temperatures”. There is not determined a threshold for the reduction in tensile properties and Shore hardness in the international standards. Therefore, a threshold of 15 % was determined for the evaluation of the compatibility. The change of tensile strength and breaking elongation of test specimens made of ACM, FKM, HNBR, PA, PE, POM, PUR and PVC exposed to heating oil and the blend B20 was less than 15 % at 40 °C. A maximum reduction in Shore hardness A of 14 % was determined for ACM at 40 °C and for HNBR of 15 % at 70 °C. It can be concluded that ACM, FKM, HNBR, PA, PE, POM, PVC and PUR were resistant in B20 at 40°C. FKM, PA, POM and PVC were evaluated as resistant in heat-ing oil and B20 at 70 °C, HNBR and PUR were not resistant in these fuels at 70°C. Based on the mass increase and compression set values of FKM test specimens it can be stated that FKM is resistant in B20 under compressed conditions at 40 °C and 70 °C. T2 - EUROCORR 2019 CY - Sevilla, Spain DA - 09.09.2019 KW - Heating oil - biodiesel - blend KW - Polymeric materials KW - Compatibility KW - Tensile properties KW - Shore Hardness PY - 2019 AN - OPUS4-49002 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rethmeier, Michael A1 - Üstündag, Ö. A1 - Gumenyuk, Andrey T1 - Single-pass Hybrid Laser Arc Welding of Thick Materials Using Electromagnetic Weld Pool Support N2 - Hybrid laser-arc welding process allows single-pass welding of thick materials, provides good quality formation of joints with minimal thermal deformations and a high productivity in comparison with arc-based welding processes. Nevertheless, thick-walled steels with a thickness of 20 mm or more are still multi-pass welded using arc welding processes, due to increased process instability by increasing laser power. One limitation factor is the inadmissible formation of gravity drop-outs at the root. To prevent this, an innovative concept of electromagnetic weld pool support is used in this study. With help of such system a stable welding process can be established for 25 mm thick steel plates and beyond. Sound welds could be obtained which are tolerant to gaps and misalignment of the welded parts. The adaptation of this system to laser and hybrid laser-arc welding process can dramatically increase the potential field of application of these technologies for real industrial implementation. T2 - Lasers in Manufacturing Conference 2019 CY - Munich, Germany DA - 24.06.2019 KW - Full Penetration KW - Hybrid Laser Arc Welding KW - Electromagnetic Weld Pool Support KW - Thick Materials PY - 2019 AN - OPUS4-48975 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rethmeier, Michael A1 - Gook, S. A1 - Üstündag, Ö. A1 - Gumenyuk, Andrey T1 - Avoidance of end crater imperfections at high-power laser beam welding of closed circumferential welds N2 - The present work deals with the development of a strategy for the prevention of end crater defects in high-power laser welding of thick-walled circumferential welds. A series of experiments were performed to understand the influence of the welding parameters on the formation of end crater defects such as pores, cracks, excessive root-side drop-through and shrinkage cavities in the overlap area. An abrupt switch-off of the laser power while closing the circumferential weld leads to a formation of a hole which passes through the whole welded material thickness. A laser power ramp causes solidification cracks which are initiated on the transition from full-penetration mode to partial penetration. Strategies with a reduction of the welding speed shows a creation of inadmissible root sagging. Defocusing the laser beam led to promising results in terms of avoiding end crater defects. Cracks and pores in the overlap area could be effectively avoided by using defocusing techniques. A strategy for avoiding of end crater imperfections was tested on flat specimens of steel grade S355J2 with a wall thickness of 10 mm and then transferred on the 9.5 mm thick pipe sections made of high-strength steel X100Q. T2 - The 72nd IIW Annual Assembly and International Conference 2019 CY - Bratislava, Slovakia DA - 07.07.2019 KW - End crater KW - Laser beam welding KW - Circumferential welds PY - 2019 AN - OPUS4-48976 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rethmeier, Michael A1 - Üstündag, Ö. A1 - Gook, S. A1 - Gumenyuk, Andrey T1 - Mechanical Properties of Single-pass Hybrid Laser Arc Welded 25 mm Thick-walled Structures Made of Fine-grained Structural Steel N2 - The presented study deals with the performing and mechanical testing of single pass hybrid laser-arc welds (HLAW) on 25 mm thick plates made of steel grade S355J2. One of the challenges have to be solved at full penetration HLAW of thick plates is the drop formation occurring due to the disbalances of the forces acting in the keyhole and on the melt pool surface. Such irregularities mostly limit the use of high-power laser beam welding or HLAW of thick-walled constructions. To overcome this problem, an innovative concept of melt pool support based on generating Lorentz forces in the weld pool is used in this work. This method allows to perform high quality welds without sagging even for welding of 25 mm thick plates in flat position at a welding speed of 0.9 m min-1. For the obtain of full penetrated welds a laser beam power of 19 kW was needed. A high V-impact energy of up to 160 J could be achieved at the test temperature of 0 °C. Even at the most critical part in the weld root an impact energy of 60 J in average could be reached. The tensile strength of the weld reaches that of the base material. An introduce of the HLAW process with electromagnetic support of the melt pool in the industrial practice is an efficient alternative to the time- and cost-intensive arc-based multi-layer welding techniques which are established nowadays for joining of thick-walled constructions. T2 - 17th Nordic Laser Materials Processing Conference - NOLAMP17 CY - Trondheim, Norway DA - 27.08.2019 KW - Full Penetration KW - Hybrid Laser Arc Welding KW - Electromagnetic Weld Pool Support KW - Thick Materials PY - 2019 AN - OPUS4-48977 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thünemann, Andreas T1 - The Single Chain Architecture of (Bio)Polymers in Contact with Nanoplastics N2 - In contrast to microplastics, little is known about nanoplastics (1 to 100 nm). In order to make the dectecability of nanoplasics more reliable, we started to develop nanoplastic reference materials. This project also aims to anser the question of how the single chain conformation of bio(polymers) changes in contact with nanoplastics. Small-angle X-ray and neutron scattering methods are suitable methods for studing this topic. Recently the soft and hard interactions between polystyrene nanoplasics and human serum albumin corona was investigated with small-angle neutron scattering. Here we concentrate on small-angle X-ray scattering as our favorite method to study how (bio)polymers change their conformation in contact with nanoplastics. The scattering of bovine serum albumin in its native state can be detected easily. The scattering pattern of this biopolymer changes dramatically when its globular stucture changes to a coil structure. Modeling of chain conformations and the calculation of the scattering pattern is relatively easy to perform. Numerous model calculations will be provided to predict the changes of conformation of single bio(polymer) chains when in conatact with nanoplastics. These predictions will be compared with recent experimenal results from in situ measurments of bio(polymers) in contact with nanoplastics. The impact of temperature, polymer concentration and salt on the single-chain conformation changes will be discussed. T2 - PolyDays 2019 CY - Berlin, Germany DA - 11.09.2019 KW - Small-angle X-ray scattering KW - SAXS KW - Nanoparticle KW - Protein KW - Nanoplastics PY - 2019 AN - OPUS4-48959 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gradt, Thomas A1 - Theiler, Géraldine T1 - Influence of cryogenic hydrogen environment on the tribological properties of materials N2 - The presentation gives an overview over the LH2-activities during 20 years of tribological research in cryogenic environments at BAM. T2 - 2019 Hydrogenius & I2CNER Tribology Symposium CY - Fukuoka, Japan DA - 30.01.2019 KW - Friction KW - Wear KW - Hydrogen KW - Cryogenic Engineering KW - Hydrogen Embrittlement PY - 2019 AN - OPUS4-47339 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gradt, Thomas T1 - Tribological Research in Germany - Overview and Examples from the Federal Institute for Materials Research and Testing (BAM) N2 - The talk gives a historical introduction and introduces some of the biggest and most important research institutes in Germany dealing with tribology at Universities, scientific societies and companies. Some examples for research projects and focus areas are given. As an example for a research institute with a long history in tribological research the activities of BAM in Berlin are presented. T2 - Joint Tribology Symposium of Kyushu University and Yokohama National University KY7 CY - Fukuoka, Japan DA - 01.02.2019 KW - Friction KW - Lubrication KW - Wear PY - 2019 AN - OPUS4-47345 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bellon, Carsten A1 - Burger, Karin A1 - Gollwitzer, Christian T1 - Virtual CT acquisition and reconstruction of complex and noisy scanning trajectories in aRTist N2 - In modern CT imaging, simulation has become an important tool to minimize cost- and time-intensive measurements. It is increasingly used to optimize techniques for complex applications, to support the preparation of written procedures, and for educational purposes. We extended the CT simulation software ‘aRTist’ with a module to set-up arbitrary trajectories including disturbing influences during the scan. Moreover, such geometric deviations can be compensated by the internal reconstruction tool. T2 - 9th Conference on Industrial Computed Tomography (iCT) CY - Padua, Italy DA - 13.02.2019 KW - Simulation KW - Arbitrary trajectories KW - Projection matrix KW - Filtered back projection PY - 2019 AN - OPUS4-47476 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lohrer, Christian T1 - Topics concerning pyrotechnic articles – news from the notified bodies N2 - Presentation of latest develeopements regarding conformity assessments of pyrotechnic articles within the forum of notified bodies according to article 37 of the EU Directive 2013/29/EU OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 12 June 2013 on the harmonisation of the laws of the Member States relating to the making available on the market of pyrotechnic articles (recast). T2 - 14th Meeting of the AdCo Pyrotechnic Articles CY - Rotterdam, The Netherlands DA - 27.02.2019 KW - Pyrotechnics KW - Notified bodies KW - Market surveillance PY - 2019 AN - OPUS4-47469 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schoenhals, Andreas T1 - Structure property relationships of thin polymer films N2 - Polymers at interfaces play a major role in a broad variety of applications ranging from engineering purposes (for instance polymer based nanocomposites) to high tech implications (for instance light emitting diodes). Here, thin films with thicknesses down to few nanometers are prepared on different substrates as model systems for polymer composites. The thin films are investigated by a combination of surface analytical and volume sensitive methods. As surface analytical methods atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and contact angle measurements (CAM) are employed. As volume sensitive broadband dielectric spectroscopy (BDS), specific heat spectroscopy (SHS), and ellipsometry are used. Especially attention is paid to understand the glass transition behavior of thin films because the glass transition is the key phenomenon determines the application of polymers also in thin films. To understand the glass transition behavior of thin films, which is controversially discussed in literature, a three layer model is discussed. Firstly, a mobile surface layer is assumed at polymer air interface of the film due to missing of segment/segment interactions. Secondly, in the middle of the film a bulk-like layer should be expected. Thirdly, for polymers having non-repulsive interactions with the substrate an irreversibly adsorbed layer is expected to be formed. Due the adsorption the molecular mobility of the segments in this layer is slowed down. What is measured for the glass transition of thin films is a complicated average of all of these effects. The different layers are hardly to address separately. Therefore, in the presentation especially model systems are selected and investigated to verify the layer model. T2 - Seminarvortrag Universität Dortmund CY - Dortmund, Germany DA - 29.01.2019 KW - Thin polymer films PY - 2019 AN - OPUS4-47289 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gollwitzer, Christian A1 - Scholz, Philipp A1 - Ulbricht, Alexander A1 - Joshi, Yogita A1 - Weidner, Steffen T1 - Synchrotron based absorption edge tomography for the analysis of 3D printed polymer MOF N2 - Absorption edge tomography is a method which exploits the sudden change of the attenuation coefficient, when the photon energy crosses the absorption edge of an element. The beamline BAM line at BESSY II, which is operated by the Federal Institute for Materials Research and Testing, can provide a monochromatized beam in a photon energy range from 5 keV up to 80 keV with a bandwidth of 2%. Together with the microtomography setup, this enables differential tomography sensitive to any element with N >= 24 (Cr) by using an appropriate K- or L-edge in this range. Here, a polymer filament embedding metal organic framework (MOF) was prepared and used for 3D printing. Absorption edge tomography at the copper K edge was employed to perform a non-destructive 3D characterization of the microstructure of the embedded MOF. Data fusion was then used to determine the size distribution of the embedded MOF. T2 - iCT 2019 CY - Padua, Italy DA - 12.02.2019 KW - Synchrotron tomography KW - BAMline KW - MOF KW - Absorption edge tomography PY - 2019 AN - OPUS4-47392 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Koch, Claudia T1 - Standardization for emerging technologies - Additive manufacturing case study N2 - This was a short presentation on the role of Standards and standardization for the development and diffusion of an emerging technology - using additive manufacturing as an example. T2 - 6th Annual Meeting of the Indo-German Working Group on Quality Infrastructure CY - Berlin, Germany DA - 17.01.2019 KW - 3D-Printing KW - Additive Manufacturing KW - Emerging technologies KW - Standardization KW - Standards KW - Technological innovation PY - 2019 AN - OPUS4-47397 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute A1 - Weigert, Florian A1 - Frenzel, Florian A1 - Würth, Christian A1 - Hoffmann, Katrin A1 - Martynenko, Irena A1 - Dhamo, Lorena T1 - Photoluminescence Properties of Different Types of Nanocrystals at the Ensemble and Single Emitter Level N2 - Correlating the photoluminescence (PL) properties of nanomaterials like semiconductor nanocrystals (QDs) and upconversion nanocrystals (UCNPs) assessed in ensemble studies and at the single particle level is increasingly relevant for applications of these nanomaterials in the life sciences like bioimaging studies or their use as reporters in microfluidic assays. Here we present a comparison of the spectroscopic properties of ensembles and single emitters for QDs like II/VI QDs and cadmium-free AIS/ZnS QDs as well as different UCNPs. The overall goal of this study was to derive particle architectures well suited for spectroscopic and microscopic applications. T2 - BIOSSPIE CY - San Francisco, CA, USA DA - 02.02.2019 KW - Quantum yield KW - Nanomaterial KW - Photoluminescence KW - Absolute fluorometry KW - Integrating sphere spectroscopy, KW - NIR KW - IR KW - Fluorescence KW - Nanoparticle KW - Semiconductor KW - Quantum dot KW - Single particle spectroscopy KW - Surface chemistry PY - 2019 AN - OPUS4-47358 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krüger, Jörg A1 - Legall, Herbert A1 - Schwanke, Christoph A1 - Bonse, Jörn T1 - X-ray emission during ultrashort pulse laser processing N2 - The industrial use of ultrashort laser pulses has made considerable progress in recent years. The reasons for this lie in the availability of high average powers at pulse repetition rates in the several 100 kHz range. The advantages of using ultrashort laser pulses in terms of processing precision can thus be fully exploited. However, high laser intensities on the workpiece can also lead to the generation of unwanted X-rays. Even if the emitted X-ray dose per pulse is low, the accumulated X-ray dose can become significant for high-repetition-rate laser systems so that X-ray exposure safety limits must be considered. The X-ray emission during ultrashort pulse laser processing was investigated for a pulse duration of 925 fs at 1030 nm wavelength and 400 kHz repetition rate. Industrially relevant materials such as steel, aluminum and glass were treated. Tungsten served as reference. X-ray spectra were recorded, and X-ray dose measurements were performed for laser treatment in air. For laser intensities > 2 × 10^13 W/cm2, X-ray doses exceeding the regulatory exposure limits for members of the public were found. Suitable X-ray protection strategies are proposed. T2 - SPIE Photonics West CY - San Francisco, USA DA - 02.02.2019 KW - Laser-induced X-ray emission KW - Ultrashort laser material interaction KW - Radiation protection PY - 2019 AN - OPUS4-47361 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Yusenko, Kirill A1 - de Oliveira Guilherme Buzanich, Ana A1 - Radtke, Martin A1 - Reinholz, Uwe A1 - Riesemeier, Heinrich A1 - Emmerling, Franziska T1 - BAMline 2.0 – further technical developments for a broader multipurpose hard X-ray beamline at BESSY II N2 - We show further development of our beamline in the contexst of further itermational collaboration. T2 - PACC and AfSC CY - Accra, Ghana DA - 28.01.2019 KW - Synchrotron radiation PY - 2019 AN - OPUS4-47317 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - de Oliveira Guilherme Buzanich, Ana T1 - Hard X-ray spectroscopy and imaging at the BAMline and MySpot beamlines at BESSY II (Berlin, Germany) N2 - Overview of the X-ray based analytical methods conducted at the BAMline and µSpot Beamline for structure analysis. T2 - Pccr2 + AfLS conference CY - Accra, Ghana DA - 29.01.2019 KW - X-ray spectroscopy KW - Synchrotron KW - Beamline KW - Material characterization PY - 2019 AN - OPUS4-47319 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Emmerling, Franziska T1 - May the Force be with you - Mechanochemical syntheses studied in situ N2 - Mechanochemistry is a fast and efficient method applicable for the synthesis of new organic, metal-organic, and inorganic compounds. The direct monitoring of milling reactions is still challenging. The underlying reaction mechanisms remain often unclear. In the last years, have established a tandem in situ approach for investigating mechanochemical reactions using time-resolved in situ XRD coupled with Raman spectroscopy. Here, we present an in situ coupling of synchrotron XRD, Raman spectroscopy, and thermography allowing the observation of mechanochemical reactions in real time. Information on the crystalline, molecular, and temperature state of the materials during grinding could be collected. The chemical composition of the reaction mixture was found to be directly correlated with changes in the temperature profile of the reaction. Furthermore, the presented setup allows the detection of crystalline, amorphous, eutectic as well as liquid intermediates. The resulting deeper kinetic and thermodynamic understanding of milling processes is the key for future optimization of mechanochemical syntheses. T2 - Seminar Universität Montpellier CY - Montpellier, France DA - 24.01.2019 KW - Mechanochemistry KW - In situ PY - 2019 AN - OPUS4-47261 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Emmerling, Franziska T1 - New insights in mechanochemical processes using real-time in situ investigations N2 - Use of synchrotron radiation for special sample conditions. Recent work of the group at BESSY II. T2 - DESY Usermeeting Satelite Workshop CY - Hamburg, Germany DA - 22.01.2019 KW - XRD KW - In situ KW - Rietveld KW - Synchrotron PY - 2019 AN - OPUS4-47262 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute A1 - Würth, Christian A1 - Kaiser, Martin A1 - Pauli, Jutta A1 - Hoffmann, Katrin T1 - Relative and Absolute Methods for Measuring Photoluminescence Quantum Yields of UV/vis/NIR Emitters N2 - One of the key spectroscopic performance parameters of molecular and particulate emitters is the photoluminescence quantum yield (PL QY) that provides a direct measure for the number of emitted per absorbed photons. This triggered the interest in methods suitable for measuring this property for emitters in various environments in the UV/vis/NIR and above 1000 nm as well as on the ensemble and single emitter level. Moreover, for nonlinear emitters like lanthanide-based upconversion nanocrystals methods including instrumentation for power density-dependent PL QY studies are required. An overview of the research activities in Division Biophotonics of BAM is given and suitable relative and absolute methods for the deter-mination of PL QY of organic dyes and different types of application-relevant nanomaterials in dispersion and in the solid state are presen-ted. This covers also the design and calibration of integrating sphere setups, achievable uncertainties, and candidates for PL QY reference materials. T2 - OSRAM Veranstaltung CY - Regensburg, Germany DA - 09.01.2019 KW - Quantum yield KW - Calibration KW - Reference material KW - Uncertainty KW - Absolute fluorometry KW - Integrating sphere spectroscopy KW - NIR KW - IR KW - Fluorescence KW - Nanoparticle KW - Dye PY - 2019 AN - OPUS4-47263 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Taparli, Ugur Alp A1 - Griesche, Axel A1 - Kannengießer, Thomas A1 - Jacobsen, L. A1 - Michalik, K. A1 - Mory, D. T1 - In situ TIG-Welding monitoring using Laser-Induced Breakdown Spectroscopy N2 - Chemical composition of the welding seam and HAZ has significant effect on weld quality. Current inspection methods for weld seams measure and investigate post factum and cannot prevent weld defects. Element burn-off may significantly affect solidification leading to embrittlement or cracking. Control of weld chemical compositions insures a controlled solidification and resistance to related weld defects. “Industry 4.0” is the current trend of automation and data exchange in manufacturing technologies. With this trend “intelligent” welding machines will be developed. LIBS can provide significantly important online data for such systems. T2 - Forschungsseminar OvGU Magdeburg CY - Magdeburg, Germany DA - 24.01.2019 KW - In situ measurement KW - LIBS TIG welding KW - Austenitic stainless steels KW - Chemical composition PY - 2019 AN - OPUS4-47266 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bruno, Giovanni A1 - Evans, Alexander T1 - Avoid living dangerously: non-destructive characterization of AM parts from powder to end-of-life N2 - The freeform and the revolutionary design possibilities offered by additive manufacturing have skyrocketed the amount of optimization studies in the realm of engineering, and metallic additive manufactured parts are becoming a reality in industry. Not surprisingly, this has not been paralleled by a similar enthusiastic wave in the realm of materials science, and still very little is known about AM materials properties. This has the consequence that, typically, conventional materials properties are still used in design and even in simulations. lt is necessary to dig a lot deeper than at present, in order to understand these new materials classes, and in particular their microstructure and their intemal stresses, largely different from their cast or wrought companions. T2 - ISAM Konferenz 2019 CY - Dresden, Germany DA - 29.01.2019 KW - Computed Tomography KW - Microstructure KW - Metals KW - Additive Manufacturing PY - 2019 AN - OPUS4-47331 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Feldkamp, Martin A1 - Quercetti, Thomas A1 - Wille, Frank T1 - Fire reference test for IAEA package thermal testing in a propane gas fire test facility N2 - Packages for the transport of radioactive material shall withstand severe accidents. Therefore, the IAEA Regulations define different test scenarios to cover severe hypothetical accident conditions. One of these tests defined in detail is the thermal test, mainly consisting of a 30 minute fully engulfing 800 °C pool fire or an equally severe fire test. The heat fluxes into the package are of significant importance and depend substantially on the fire characteristics and the surface temperature of the package. In order to investigate the heat fluxes over a wide range of surface temperatures during a propane gas fire test and to get information about local fire impact a fire reference package, representing the outer geometry of a specific type of transport cask for radioactive waste, was designed. A closed steel sheet cylinder with a wall thickness of 10 mm was chosen as fire reference package. The cylinder was filled with refractory insulation material and instrumented with thermocouples distributed all over the cylinder. The local steel sheet temperatures measured allow the determination of local as well as global heat fluxes as a function of time and surface temperature. With this fire reference package three open-air propane gas fire tests were performed at BAM’s open air fire test stand. The flame exposure time period was changed for the different fire tests. Furthermore, the wind conditions changed between and during the tests. Test stand parameters like wind shield location and propane gas volume flow were chosen constant for the three tests. The test results were used to determine the changes of heat flux into the fire reference package in relation to the package surface temperature. This data also allows the calculation of local characteristics of the propane gas fire as there are the flame temperature, the fire convection coefficient and the radiation exchange coefficient in a first approach. The recently conducted tests provide an initial picture of local fire characteristics of the propane gas fire test facility. The test shows that the propane gas fire covers the IAEA-fire over a wide range of surface temperatures with the chosen test stand parameters. T2 - 19th International Symposium on the Packaging and Transportation of Radioactive Materials PATRAM 2019 CY - New Orleans, LA, USA DA - 04.08.2019 KW - Thermal testing KW - Convection coefficient KW - IAEA fire KW - Propane gas fire test facility PY - 2019 AN - OPUS4-48841 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kömmling, Anja A1 - Jaunich, Matthias A1 - Wolff, Dietmar T1 - Comparison of different test methods for lifetime prediction of O-ring seals N2 - Elastomeric O-ring seals are used in a wide range of applications due to their excellent elasticity. However, like all polymers, elastomers degrade under the influence of e.g. time, temperature, oxygen, radiation and mechanical stress. Especially in applications where a replacement of seals after a certain time is hard or almost impossible, it is important to know the seal lifetime. Therefore, an extensive ageing programme with elastomers made of EPDM, HNBR and other materials was started with the aim of determining suitable methods for accelerated ageing and lifetime prediction. In order to determine the lifetime of polymeric parts, the time-temperature superposition principle is commonly used to shift property changes obtained by accelerated ageing at higher temperatures to lower temperatures. If the shift factors yield a straight line in an Arrhenius diagram, a corresponding activation energy can be determined. However, we have found that the shift factors and thus the predicted lifetime depends on the test method that yielded the shifted data. For example, the shift factor between 125 °C and 150 °C ageing temperature was roughly the same (5/5/4.5 respectively) for hardness, density and maximum of loss factor tan  measured on HNBR, but different for elongation at break (8) and compression set (2.2, excluding DLO-affected data). A possible explanation might be that while the different oxidation reactions proceed with a fixed activation energy, they have differing impact on the measured properties. For example, hardness is lowered by chain scission reactions, and increases by crosslinking reactions during ageing. As usually both chain scission and crosslinking reactions occur during ageing, the measured hardness increase reflects only the net effect of both reaction types. On the other hand, compression set is influenced additively by both reaction types: chain scission leads to an increase of the remaining deformation, as broken chains lose their recovery potential, and crosslinking reactions during ageing fix the compressed geometry, which also leads to less recovery. Thus, compression set reflects the total number of changes in the network and shows degradation effects much faster, which results in lower shift factors and lower activation energy. This phenomenon was observed for EPDM as well. In order to verify our hypotheses and to gain further insights, temperature-dependent oxygen consumption measurements are currently being performed and results will be presented at the conference. The shift factors and activation energy determined by oxygen consumption measurements are expected to be close to the values for compression set. T2 - Polymer Degradation Discussion Group Conference CY - Malta DA - 01.09.2019 KW - Compression set KW - Time-temperature superposition KW - Arrhenius KW - HNBR KW - EPDM KW - FKM KW - Activation energy PY - 2019 AN - OPUS4-48907 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lugovtsova, Yevgeniya A1 - Johannesmann, S. A1 - Henning, B. A1 - Prager, Jens T1 - Analysis of Lamb wave mode repulsion and its implications to the characterisation of adhesive bonding strength N2 - Lamb waves are widely used for non-destructive evaluation of material parameters as well as for detection of defects. Another application of Lamb waves is quality control of adhesive joints. Researchers are currently investigating shear horizontal and zero-group velocity modes for characterisation of the adhesive bonding strength. In a new approach, Lamb wave mode repulsion is used to obtain the coupling strength between different layers to characterise the adhesive bonding strength. The modes of the individual layers become coupled in the multilayered systems forming particular regions, the so-called mode repulsion regions. This study investigates these modes and their interaction in two-layered plate-like structures with varying coupling strength both numerically, with the Scaled Boundary FEM, and experimentally. T2 - International Congress on Ultrasonics CY - Bruges, Belgium DA - 03.09.2019 KW - Lamb waves KW - Multi-layered system KW - Adhesive joint KW - Mechanical strength KW - Scaled Boundary FEM PY - 2019 AN - OPUS4-48910 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Baensch, Franziska A1 - Brunner, A. J. T1 - Towards predictor development for assessing structural integrity of components made from wood materials using Acoustic Emission monitoring and signal analysis N2 - Against the background of sustainable resource management and efficiency, wood-based materials are currently experiencing a revival and, among others, plywood, Laminated Veneer Lumber and glued laminated timber are becoming increasingly more important in the building sector. Even though these materials are so-called engineered products, the element wood is naturally grown with intrinsic variability in mechanical properties and requires professional handling on-site. Otherwise, load-bearing structures made of wood materials may entail certain risks. Critical situations can, in principle, be avoided by implementing a structural health monitoring system into components or structures made from wood material. The aim is to indicate accumulation of mechanical damage and to eliminate or at least significantly reduce the risk of unexpected failure. Toward this purpose, the failure behavior of several layered wood materials under quasi-static tension was investigated in laboratory-scale experiments by means of acoustic emission (AE) measurement. Based on spectral analysis and pattern recognition, two classes of AE signals are identified for each investigated lay-up that are characterized by either low or high frequency contents in the respective power spectra. AE activity and intensity of both signal classes are analyzed, striving for predictors appropriate for AE monitoring concepts. T2 - 5th International Conference on Smart Monitoring, Assessment and Rehabilitation of Civil Structures CY - Potsdam, Germany DA - 27.08.2019 KW - Wood materials KW - Acoustic Emission KW - Structural integrity PY - 2019 AN - OPUS4-48802 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Serrano Munoz, Itziar A1 - Mishurova, Tatiana A1 - Thiede, Tobias A1 - Nadammal, Naresh A1 - Bruno, Giovanni T1 - Influence of scanning strategies on the development of residual stresses in a LPBF IN718 alloy N2 - This presentation is a brief summary on the activites that 8.5 division has been carrying out on the measurements of residual stresses of a Laser Power Bed Fusion IN718 alloy. T2 - Euromat 2019 CY - Stockholm, Sweden DA - 02.09.2019 KW - Laser Powder Bed Melting KW - AM IN718 alloy KW - Residual stresses KW - Neutron diffraction KW - Synchrotron Energy Dispersive Diffraction PY - 2019 AN - OPUS4-48895 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sachse, René A1 - Hodoroaba, Vasile-Dan A1 - Hertwig, Andreas A1 - Matjacic, L. A1 - McMahon, G. A1 - Kotil, L. A1 - Bernsmeier, D. A1 - Kraehnert, R. T1 - Analysis of elemental composition and porosity of mesoporous iridium titanium mixed oxide thin films for energy application by SEM/EDS N2 - Porous materials play an important role in several fields of technology, especially for energy applications like photovoltaics, electrolysis or batteries. The activity of porous films is affected by properties like porosity, film thickness, chemical composition of the material as well as the crystallinity of the framework. The complex morphology of such porous films constitutes a challenge even for modern analytical techniques and requires new approaches employing the combination/complementation of data of different analytical methods. In this contribution we characterize thin mesoporous iridium-titanium mixed oxide film properties by Electron Probe Microanalysis (EPMA) with energy dispersive X-ray spectroscopy (EDS) at an SEM. T2 - Microscopy & Microanalysis 2019 Meeting CY - Portland, OR, USA DA - 04.08.2019 KW - Mesoporous mixed metal oxide films KW - SEM/EDS/STRATAGem KW - EPMA KW - Ellipsometry KW - NanoSIMS PY - 2019 AN - OPUS4-48767 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stephan-Scherb, Christiane T1 - Unravelling high temperature oxidation phenomena by in situ x-ray techniques N2 - Unravelling high temperature oxidation phenomena by in situ x-ray techniques. A multi techqnique approach to study high temperature gas corrosion is presented. T2 - Gordon Research Conference on High Temperature Corrosion CY - New London, NH, USA DA - 20.07.2019 KW - Corrosion KW - High temperature KW - Diffraction KW - Spectroscopy PY - 2019 AN - OPUS4-48772 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Waniek, Tassilo A1 - Zarinwall, A. A1 - Silbernagl, Dorothee A1 - Garnweitner, G. A1 - Sturm, Heinz T1 - Mechanical coupling of matrix and nanoparticles depending on particle surface modification N2 - Boehmite nanoparticles has been successfully functionalized with APTES. After APTES functionalization further modification with tailored molecules e.g. via carboxylic acids is possible. The tailored surface functionalization is strongly enhanced by improved coupling protocols. Arbitrary variation of the functionalization degree is possible. Thereby the temperature stable APTES functionalization enables a wide range of functional groups. By TGA-MS analysis strong evidence for the bonding situation of the APTES on the boehmite surface has been found. Additionally first experiments has been performed to predict the polymer-particle compatibility enhancement via reverse wetting angle measurements with AFM. T2 - Workshop Acting Principles of Nano-Scaled Matrix Additives for Composite Structures CY - BAM, Berlin, Germany DA - 11.10.2019 KW - Surface modification KW - Nanocomposites KW - Boehmite KW - Silane KW - Thermogravimetry KW - Mass spectrometry PY - 2019 AN - OPUS4-49435 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Evans, Alexander A1 - Bruno, Giovanni A1 - Sprengel, Maximilian A1 - Madia, Mauro A1 - Kromm, Arne T1 - Residual stresses in Laser Beam Melting (LBM) – Critical Review and outlook of activities at BAM N2 - Additive manufacturing (AM) technologies have experienced an exceedingly rapid growth, which is coupled with the knowledge about the resulting material properties and performance. In particular, residual stress (RS) was soon recognized as an important issue in AM parts, such that parts are usually subjected to a post build-heat-treated. Significant effort has been spent on simulations of RS in AM, especially using finite element methods. As a consequence, the experimental determination of RS has thereby become increasingly important as a validation tool for simulations, as well as a method for assessing the influence of process parameters. In particular, diffraction methods, which are fundamentally non-destructive, offer enormous possibilities to gain knowledge on the residual stress state in real components, since synchrotron radiation and neutrons can penetrate even heavy metals up to several millimeters or centimeters, respectively. Indeed, significant progress has been achieved, in the understanding of the origins of the RS fields as a function of process parameters, as well as their stability under thermal and/or mechanical exposure. In this paper, a few success stories will be outlined. It will be shown how the determination of RS in metallic parts (with the focus on those produced by laser powder bed fusion) has even revealed that process parameters that were previously considered unimportant (e.g. the position and orientation on the base plate) play a major role in the onset of residual stress accumulation. However, while RS characterization is starting to be considered in the component design, deposition strategy (e.g. build plate temperature), and even in the definition of the relevant metric to assess the quality of a part, much is still to be investigates about the hypotheses underlying its experimental determination. Therefore, some aspects to be aware of, or even those which to date are unclear, will also be discussed. These include the determination of the stress-free reference and of the principal axes of stress. All of these aspects will lead towards a comprehensive understanding of the process-structure-performance relationships in AM materials and parts. T2 - Fourth ASTM Symposium on Structural Integrity of Additive Manufactured Materials and Parts CY - Gaylord National Resort And Convention Center; National Harbor, MD DA - 07.10.2019 KW - Diffraction KW - Additive Manufacturing KW - Residual stress PY - 2019 AN - OPUS4-49367 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Charmi, Amir A1 - Falkenberg, Rainer A1 - Skrotzki, Birgit A1 - Ávila, Luis A1 - Sommer, Konstantin T1 - Virtual-lab-based determination of a macroscopic yield function for additively manufactured parts N2 - This work aims for an yield function description of additively manufactured (AM) parts of S316L steel at the continuum-mechanical macro-scale by means of so-called virtual experiments using a crystal plasticity (CP) model at meso-scale. Additively manufactured parts require the consideration of the specific process-related microstructure, which prevents this material to be macroscopically treated as isotropic, because of crystallographic as well as topological textures. EBSD/CT-Scans from in-house additively manufactured specimen extract the unique microstructural topology which is converted to a representative volume element (RVE) with grain structure and crystal orientations. Crystal plasticity model parameters on this RVE are calibrated and validated by means of mechanical testing under different texture angles. From virtual experiments on this RVE, yield loci under various loading conditions are simulated. The scale bridging from meso- to macro-scale is realised by the identification of the simulated yield loci as a modified anisotropic Barlat-type yield model representation. T2 - The First European Conference on Structural Integrity of Additively Manufactured Materials (ESIAM19) CY - Trondheim, Norway DA - 09.09.2019 KW - Virtual experiments KW - Additive manufacturing KW - Anisotropy KW - Crystal plasticity KW - Scale-bridging PY - 2019 AN - OPUS4-49376 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Koerdt, Andrea A1 - An, Biwen Annie A1 - Kleinbub, Sherin A1 - Herrmann, Annett T1 - Investigation of methanogen-induced microbiologically influenced corrosion (Mi-MIC) using simulated marine environments under flowing conditions N2 - Microbiologically influenced corrosion (MIC) of iron is usually attributed to sulfate-reducing microorganisms (SRM) in offshore industries, such as the oil and gas pipelines, due to the high concentrations of sulfate in the seawater. SRM act upon the metal by the reactiveness of hydrogen sulfide (HS-), and by withdrawal of the available electrons (Fe --> Fe2+ + 2e-; E° = -0.47 V) in electrical contact with the metal (EMIC). However, methanogenic archaea can also cause MIC. Because they do not produce HS-, withdrawal of electrons may be their main corrosive mechanism; however, mechanistic details and kinetics of the overall process are poorly understood. To investigate the corrosion potential of methanogens, we studied the EMIC methanogenic strains isolated from marine sediments (Methanobacterium-affiliated strain IM1) and crude oil tanks (Methanococcus maripaludis Mic1c10), in an in-house developed flow-through cell to simulate a fluctuating environment. A co-culture of M. maripaludis and D. alaskensis was also established to study the effect of syntrophic growth on metal corrosion that may occur in industrial pipelines. Results indicate that the rates of iron corrosion due to coupled methanogenesis (up to 0.4 mm/yr) are higher to that caused by the marine SRM Desulfovibrio alaskensis (0.15 mm/yr). Surface analyses of the metal showed severe pitting with high methane production. Genomic analysis of the EMIC methanogen M. maripaludis Mic1c10 will provide an insight on the mechanisms of MIC. Such knowledge and deeper understanding also from an electrokinetic point of view may not only provide further models in microbial electrophysiology, but also contribute to mitigation strategies in MIC T2 - Archaea Meeting-Schmitten VAAM Fachgruppe CY - Schmitten, Germany DA - 12.09.2019 KW - Corrosion KW - MIC KW - Archaea KW - Methanogens KW - Environmental Simulation PY - 2019 AN - OPUS4-49405 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Werner, Tiago A1 - Madia, Mauro A1 - Zerbst, Uwe A1 - Sprengel, Maximilian A1 - Ulbricht, Alexander A1 - Evans, Alexander T1 - Experimental investigation on cyclic R-curves for additively manufactured 316L steel N2 - The present study deals with the experimental characterization of short crack propagation in SLM (selective-laser-melting) manufactured stainless steel. More specifically, the determination of cyclic R-curves is discussed. This describes the dependency of the crack propagation threshold on crack growth during the short crack propagation stage. For metals, the threshold, starting at a material-intrinsic value, increases until it reaches a value independent of the crack length due to crack closure phenomena which build up at that stage. The cyclic R-curve, when used in the frame of a cyclic R curve analysis, characterizes the resistance of a material to fatigue crack growth and the ability to arrest a physically short crack. Thus, it is the link between classical fatigue and fracture mechanics. In the high-cycle-fatigue range, the short crack propagation stage dominates the overall lifetime, i.e., the number of cycles until failure. Below the fatigue limit crack arrest of hitherto propagable micro-cracks will occur. The effort for the experimental characterization of the short fatigue crack propagation behavior and the cyclic R-curve is very high compared to experiments on long crack propagation. A very exact measurement of crack extension is required, since small increments need to be depicted. Pre-cracking must leave a closure free initial crack, since closure must be build up only by the cyclic R-curve. The closure-free status is achieved by compression pre-cracking. The aim of the present study is an insight into the influence of an AM process on the short crack propagation threshold. Cyclic R-curves are experimentally determined at different load-ratios for 316L austenitic steel specimens produced by SLM and conventional manufacturing. Residual stresses are measured in the crack plane and their influence on the cyclic R-curve is discussed. T2 - ESIAM19 CY - Trondheim, Norway DA - 09.09.2019 KW - fatigue crack growth KW - Additive Manufacturing KW - 316L KW - Cyclic R-curve KW - Laser Powder Bed Fusion KW - AM KW - L-PBF PY - 2019 AN - OPUS4-49412 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Madia, Mauro A1 - Werner, Tiago A1 - Sprengel, Maximilian A1 - Evans, Alexander A1 - Serrano Munoz, Itziar A1 - Zerbst, Uwe T1 - Effect of residual stresses on crack propagation in Laser Beam Melted (LBM) additively manufactured 316L N2 - Residual stresses count among the most limiting factors in the application of additively manufactured materials in safety relevant components subject to cyclic loading. The source of such stresses is inherent in the manufacturing Laser Beam Melted (LBM) process due to rapid cooling and solidification and their distribution in the specimen or component is not homogeneous, but it is usually characterized by high gradients. Moreover, the magnitude of the residual stress field depends very much on the orientation, being higher in the build direction. Many works in the literature advise to carry out a post-LBM treatment to relieve residual stresses, even though particular attention should be paid in choosing the parameters for the thermal treatment in order to avoid microstructural/phase transformations, which would affect greatly the mechanical properties of the material. Particularly in the case of the austenitic stainless steel 316L, it has been shown that annealing at high temperatures (above 900°C), besides relieving the residual stresses, may cause recrystallization, grain growth and even phase transformation. In contrast, if a too low annealing temperature is chosen in order to preserve the microstructure, the residual stresses cannot be completely relieved. This work aims to address the effect of residual stresses on short and long crack propagation for SEN(B) specimens made of 316L fabricated by LBM, in which notches have been machined by electro-discharge machining (EDM) on the mid-plane, perpendicular to the build direction. The specimens underwent different annealing treatments in inert atmosphere, in which the maximum temperature has been varied up to 900°C. The amount of residual stresses and their distribution has been measured by X-ray and neutron diffraction and the specimens have been subject to cyclic loading in a resonant testing machine. The tests show a massive influence of the residual stresses in the build direction on the resistance to fatigue crack propagation of additively manufactured 316L. Finally, a comparison with conventionally manufactured 316L is presented. T2 - Fourth Symposium on Structural Integrity of Additive Manufactured Materials and Parts CY - Gaylord National Resort And Convention Center; National Harbor, MD, USA DA - 07.10.2019 KW - Fatigue Crack Propagation KW - Additive Manufacturing KW - Residual Stresses PY - 2019 AN - OPUS4-49415 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fabry, Çağtay A1 - Pittner, Andreas A1 - Rethmeier, Michael T1 - Digitalization and Open Science in Welding Research N2 - The talk will give an overview of past, ongoing and future activities at BAM welding divisions, specifically those regarding prospects and challenges of the ongoing digital transformation and the move to more accessible research data (open science) with concerns to welding research. We will discuss current ways to publish and share research results inside the welding community and highlight approaches and advancements from other scientific fields to improve accessibility and reproducibility. We would also like to discuss the feasibility of integrating open science principles into the current IIW landscape of meetings, publications and education. In Addition we will introduce our upcoming series of workshops organized by BAM focusing on defining and implementing an open source file format specifically designed to publish and exchange high quality welding research data. T2 - The 72nd IIW Annual Assembly and International Conference 2019 CY - Bratislava, Slovakia DA - 07.07.2019 KW - Digitalization KW - Open science KW - Welding KW - Open data KW - Research data management PY - 2019 AN - OPUS4-49381 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fabry, Çağtay A1 - Pittner, Andreas A1 - Rethmeier, Michael T1 - WelDX - towards a common file format for open science in welding N2 - WelDX is a newly started research project at BAM publicly funded by the German Federal Ministry of Education and Research. Over the course of three years the project aims to build the foundation for a publicly accessible file format and to foster research collaboration in arc welding on a national and international level. The talk will motivate benefits and discuss challenges of using a common file format designed to describe, store and share arc welding research data in the scope of "Open Science". By using common open source software and tools, welding data will be made more accessible and reusable so that new scientific practices may emerge. The proposed file format aims to be easy to use for common welding applications while also offering the possibility to describe complex experiments for state of the art welding research. In addition the talk will illustrate how in the future other facilities and researchers will be able to use experimental arc welding data generated at BAM for their own research, for example to conduct their own data analysis or welding process and thermo-mechanical simulations. T2 - The 72nd IIW Annual Assembly and International Conference 2019 CY - Bratislava, Slovakia DA - 07.07.2019 KW - Welding KW - Research data management KW - Open science KW - Open data KW - Digitalization PY - 2019 AN - OPUS4-49382 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mohr, Gunther A1 - Altenburg, Simon A1 - Ulbricht, Alexander A1 - Hilgenberg, Kai T1 - In-situ defect detection in Laser Powder Bed Fusion (L-PBF) by using thermography and optical tomography N2 - Laser powder bed fusion (L-PBF) is one of the most promising additive manufacturing (AM) technologies for the production of complex metallic real part components. Due to the multitude of factors influencing process conditions and part quality and due to the layer-wise characteristic of the process, monitoring of process signatures seems to be mandatory in case of the production of safety critical components. Here, the iterative process nature enables unique access for in-situ monitoring during part manufacture. In this talk, the successful test of the synchronous use of a high-frequency infrared camera and a camera for long time exposure, working in the visible spectrum (VIS) and equipped with a near infrared filter (NIR), will be introduced as a machine manufacturer independent thermal detection monitoring set-up. Thereby, the synchronous use of an infrared camera and a VIS NIR camera combines the advantages of high framerate and high spatial resolution. The manufacture of a 316L stainless steel specimen, containing purposely seeded defects and volumes with forced changes of energy inputs, was monitored during the build. The measured thermal responses are analysed and compared with a defect mapping obtained by micro X-ray computed tomography (CT). The first results regarding methods for data analysis, derived correlations between measured signals and detected defects as well as sources of possible data misinterpretation are presented in this talk. T2 - 45. MPA Seminar - Fit for Future – Advanced Manufacturing Technologies, Materials and Lifetime CY - Stuttgart, Germany DA - 01.10.2019 KW - Data fusion KW - Laser Powder Bed Fusion (L-PBF) KW - Selective Laser Melting (SLM) KW - Additive Manufacturing (AM) KW - Process monitoring KW - Infrared thermography KW - Optical tomography KW - Computed tomography (CT) KW - Lack-of-fusion PY - 2019 AN - OPUS4-49386 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mohr, Gunther A1 - Seeger, Stefan A1 - Hilgenberg, Kai T1 - Measurement of particle emissions in Laser Powder Bed Fusion (L-PBF) processes and its potential for in-situ process monitoring N2 - Laser Powder Bed Fusion (L-PBF) is a promising additive manufacturing (AM) technology for metal part production especially for complex and lightweight structures or functional designs. In L PBF processes several by-products including welding plume and its condensates, spatter and ejected powder are generated during laser exposure. Investigations of micro- and nano-sized by-products have received little attention in literature. This study focuses on the analysis of particle emissions in L PBF of 316L stainless steel using a scattered light aerosol spectrometer and a fast mobility particle sizer spectrometer during the process which allows for in-situ analysis of particle sizes in the range of 6 nm to 100 µm. A distinct correlation of emission signals to part position can be revealed. In addition, a significant influence of laser scanning vector directions on emission signals is presented. Furthermore, differing powder layer thicknesses can be recognised by deviations in emission signals. T2 - Euro PM2019 CY - Maastricht, The Netherlands DA - 13.10.2019 KW - Aerosol measurements KW - Laser Powder Bed Fusion (L-PBF) KW - Additive Manufacturing (AM) KW - Spatter KW - Fume KW - Plume KW - Particle gas emission PY - 2019 AN - OPUS4-49387 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hübner, Oskar A1 - Kage, Daniel A1 - Hoffmann, Katrin A1 - Wegner, Karl David A1 - Dhamo, Lorena A1 - Göhde, W. A1 - Resch-Genger, Ute T1 - Luminescence lifetime encoding for flow cytometry with quantum-dot-encoded beads N2 - Spectral encoding of cells or particles and the discrimination of multiple spectral codes are a critical process in flow cytometry (FCM). Typical issues in spectral encoding are, e.g., the spectral overlap of codes, or the increasing complexity of instruments . The exploitation of the photoluminescence lifetime (LT) as an encoding parameter could be used to circumvent both of these issues, as it adds another dimension to the parameter space, or, when used as a stand-alone parameter, requiring only one excitation light source and one detector. While LT encoding was considered already decades ago it is still not implemented as a routine technique in FCM yet, mainly due to the challenge of very few photons being available within the limited transition time of a cell or particle through the laser spot. Recently, we demonstrated LT-FCM based on luminophores with ns LTs in a compact and low-cost flow cytometer. Measurements on polymer microbeads containing luminophores with distinctly different excited state LTs enabled the complete discrimination of three LT codes and five codes in total could be identified. Now, we have extended our approach towards considerably longer LTs by custom-made polymer microbeads loaded with different ratios of InP/ZnS and AgInS2 quantum dots. The use of these materials significantly expands the usable time range for LT encoding to up to several hundred ns. Our studies demonstrate the possibility to further increase the number of viable LT codes for multiplexing in LT-FCM without the need for extensive hardware modifications. T2 - Visions in Cytometry - 29th Annual Conference of the German Society for Cytometry CY - Berlin, Germany DA - 25.07.2019 KW - Multiplexing KW - Lifetime KW - Bead KW - Flow cytometry KW - Fluorescence KW - Quantum dot KW - InP KW - AIS KW - Dye KW - Encoding KW - Barcoding KW - Assay KW - Method PY - 2019 AN - OPUS4-49390 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Simkin, Roman A1 - Kranzmann, Axel A1 - Pfennig, Anja T1 - Selective oxidation of FeCr and FeCrCo model alloys in dry synthetic air N2 - The life time of mechanical components in high temperature applications is basically determined by their workings. Corrosion determines the loss of material corresponding to the loss of the effective load-bearing section and consequently increasing stress levels. To improve the material selection for such applications a numerical life prediction corrosion model for different alloys and environments is needed. Based on the ferritic alloys FeCr and FeCrCo a first quantitative model is to be developed. For this purpose, the alloys are aged at 600 °C, 650 °C and 700 °C in synthetic air under normal pressure for between 10 and 240 hours. The first objective is to establish a quantitative relationship between the oxidation rate as a function of composition and microstructure of the alloys. The influence of the inner interface as an essential parameter for transport by diffusion on the oxidation kinetics is discussed in this paper. T2 - EUROCORR 2019 CY - Sevilla, Spain DA - 09.11.2019 KW - High temperature corrosion KW - Ooxidation KW - Synthetic air KW - Modeling KW - FeCr- alloys PY - 2019 AN - OPUS4-49465 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Voigt, Marieke A1 - von Werder, Julia A1 - Meng, Birgit T1 - Investigation of the zonation of thermally treated ultra high performance concrete N2 - Ultra high performance concrete (UHPC) is characterised by its high compressive strength of more than 150 MPa and its high durability. Due to thermal treatment at 90°C a strength comparable to the 28-days-strength can be achieved immediately after the treatment and in some cases can be even further increased up to 30 %. The explanations for the increase in strength are the accelerated hydration of the clinker minerals and the intensified pozzolanic reaction contributing to a denser microstructure and hence, a high performance in compressive strength. Former research shows that thermal treatment can lead to inhomogeneities in form of a visible zonation within the cross-section. The width of the margin increases with shorter pre-storage time before the thermal treatment and with omitting protective measures against desiccation during the treatment. Specimens exhibiting a zonation typically show a lower compressive strength compared to the undisturbed reference whereas changes in chemistry, mineral content and microstructure were not reported in detail. In this study the zonation of thermally treated UHPC is investigated with respect to its chemistry, mineral composition and microstructure to allow predictions on durability and strength development. Measurements show a change in pore sizes, minerals phase composition and element distribution leading to the visible zonation and weaker bending tensile strength compared to the reference. T2 - 2nd International Conference of Sustainable Building Materials CY - Einhoven, Netherlands DA - 11.08.2019 KW - UHPC KW - Thermal treatment KW - Zonation KW - Desiccation KW - Microstructure KW - Durability PY - 2019 AN - OPUS4-49472 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Florian, Camilo A1 - Kirner, Sabrina V. A1 - Krüger, Jörg A1 - Bonse, Jörn T1 - Applications on Surface Functionalization by Laser-Induced Periodic Surface Structures (LIPSS) N2 - In recent years, the understanding on the formation of laser-induced periodic surface structures (LIPSS) has led to an emerging variety of applications that modify the optical, mechanical and chemical properties of many materials. Such structures strongly depend on the used polarization and are formed usually after irradiation with ultrashort linearly polarized laser pulses. Some specific formation mechanisms to explain every situation are still to be uncovered, but the most accepted explanation relies on the interference of the incident laser beam with electromagnetic surface waves that propagate or scatter at the surface of the irradiated materials. This leads to an intensity modulation that is finally responsible for the selective ablation in the form of parallel structures with periodicities ranging from hundreds of nanometers up to some micrometers. The versatility when forming such structures is based on the high reproducibility with different wavelength, pulse duration and repetition rate laser sources, customized micro- and nanometric spatial resolutions and compatibility with industrially relevant processing speeds when combined with fast scanning devices. In this contribution, we review the latest applications in the rapidly emerging field of surface functionalization through LIPSS, including biomimetic functionalities on fluid transport, control of the wetting properties, specific optical responses in technical materials, improvement of tribological performance on metallic surfaces and bacterial and cell growth for medical devices among many others. T2 - 38th International Congress on Applications of Lasers and Electro Optics (ICALEO 2019) CY - Orlando, FL, USA DA - 07.10.2019 KW - Laser-induced periodic surface structures, LIPSS KW - Femtosecond laser ablation KW - Surface functionalization KW - Applications PY - 2019 AN - OPUS4-49473 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Frei, Vivian A1 - Thiele, Marc A1 - Pirskawetz, Stephan A1 - Meng, Birgit A1 - Rogge, Andreas T1 - Characterizing the Fatigue Behavior of High-Performance Concrete for Wind Energy Structures N2 - Severe mechanical fatigue conditions for worldwide proliferating windfarms are a Major challenge for high-performance concrete in towers, connecting joints and foundations of wind turbines. High-performance concrete offers potential for the application in offshore windfarms, not only regarding its good mechanical, but also chemical resistivity due to low diffusivity in the highly densified microstructure. For a more reliable fatigue assessment, monitoring based on nondestructive testing can be a valuable complement to design rules. Both approaches demand reliable experimental data, information about scalability and the development of standardized testing methods. This article presents results of an ongoing research program of BAM (Bundesanstalt für Materialforschung und -prüfung), which is a part of a joint national project (WinConFat) funded by the German Federal Ministry for Economic Affairs and Energy. The subproject implemented by BAM examines the fatigue behavior in dependence of size and slenderness for varying concrete strength at different stress levels. Besides fatigue strength, nondestructive testing is carried out additionally. Methods used are strain measurement and ultrasonic testing. The change of strain, stiffness and ultrasonic pulse velocity in the fatigue process is discussed. Results disclose a deeper insight into the damage process under cyclic loading of high-performance concrete and contribute to improve nondestructive monitoring. T2 - LORCENIS - Long Lasting Reinforced Concrete for Energy Infrastructue under Severe Operating Conditions CY - Gent, Belgium DA - 10.09.2019 KW - Compressive Cyclic loading KW - Fatigue KW - High-strength concrete KW - Non destructive testing KW - Ultrasonic testing PY - 2019 AN - OPUS4-49474 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Zerbst, Uwe A1 - Madia, Mauro A1 - Hildenberg, Kai A1 - Hrabe, N. T1 - Thoughts on damage tolerance and safe life design in metallic AM structures N2 - Der Vortrag bietet eine Diskussion zur Abschätzung des Schadenstoleranzverhaltens metallischer AM - Komponenten. Im Fokus stehen Probleme bei der Ermittlung repräsentativer Materialdaten, der Einfluss von Materialdefekten und Eigenspannungen. Ausgehend von derzeitigem Stand auf dem Gebiet werden Möglichkeiten der Schadenstoleranten Bauteileauslegung von AM diskutiert. N2 - The presentation provides a discussion and damage tolerant assessment of metallic AM components. In the focus are problems of the determination of representative material data, the effect of material defects and residual stresses. Starting with the actual state-of-the-art in the field, options and possibilities of a damage tolerant design for AM are discussed. T2 - BAM/NIST-Workshop on Fatigue of Additive Manufactured Metallic Components CY - Berlin, Germany DA - 16.05.2019 KW - Schadenstolerante Bauteilauslegung KW - Repräsentative Werkstoffeigenschaften KW - Defekte Eigenspannung KW - Damage tolerant component design KW - Representative material properties KW - Residual stresses PY - 2019 AN - OPUS4-48810 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Geißler, Daniel A1 - Resch-Genger, Ute T1 - Development of reference materials (WP1) and reference methods (WP2) for the standardisation of concentration measurements of extracellular vesicles N2 - BAM provides leading expertise in preparation, characterisation and application of fluorescent reference standards and biomedical relevant nanomaterials, as well as in traceable, absolute, and quantitative fluorometric measurements of transparent and scattering systems in the ultraviolet, visible, and near infrared spectral region. BAM will prepare solid low-RI particles in WP1, will develop reference methods to determine the fluorescence intensity and RI of reference materials in WP2, and will measure the fluorescence intensity of EVs in biological test samples of WP3. T2 - EMPIR 18HLT01 "MetVesII" Kick-off meeting CY - Delft, The Netherlands DA - 17.06.2019 KW - Reference materials KW - Reference methods KW - Extracellualr vesicles PY - 2019 AN - OPUS4-48813 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Buljak, V. A1 - Bruno, Giovanni T1 - Modeling of elastic modulus evolution in porous ceramics due to thermally induced cracking N2 - Within polycrystalline porous ceramics used in automotive applications as diesel particulate filters, it is evidenced that during cooling from firing temperature micro cracks are gradually formed. The cracks are formed as a consequence of strong thermal anisotropy of grains. Typically these micro cracks are granting better thermal shock resistance, with respect to dense materials, but reduce stiffness. The reduction can be quantified by measuring the drop in elastic properties of bulk material which, depending on the level of porosity, can decrease even by 50% with respect to its value at high temperature. It is further observed that upon subsequent heating these cracks are closing and partially or totally healing at very high temperatures. Such peculiar behavior results in partial or complete recovery of the elastic properties of bulk material upon completing one thermal cycle. Despite its evident practical application, still there is no constitutive description of this phenomenon, capable of predicting the evolution of Young's modulus as a function of temperature history. For reliable numerical simulation of this phenomenon, it is required to model fracture. To model inter-crystalline fracture, an effective strategy is to use cohesive elements, since crack patterns are a priori known. Major limitation of this approach is that the cohesive elements already implemented within commercial codes cannot take into account crack healing upon subsequent heating. In this study new cohesive element is developed and numerically implemented within ABAQUS commercial finite element code, capable to model crack opening, closing and healing. Further on, a computer code is generated to build numerical model of porous ceramic specimens that takes into account experimentally measured crystallographic orientation and porosity, and models the microstructure by using Voronoi polygons. The developed numerical tools serve as a framework for more realistic simulations, required to study the hysteresis in elastic properties within porous ceramics provoked by thermal cyclic. In a subsequent phase, an inverse analysis procedure is developed, in which macroscopic properties are used to calibrate parameters entering into micro crack model. The approach is centered on a minimization of a discrepancy function designed to quantify the difference between experimentally measured quantities and their computed counterpart. The model is calibrated on the basis of experimental data regarding the drop of bulk Young's modulus with decrease of temperature. Developed procedure is tested with porous cordierite sample, and obtained results are quit promising despite the current limitation of using only two-dimensional model. T2 - European Ceramic Society Conference 2019 CY - Turin, Italy DA - 16.06.2019 KW - Microcracking KW - Cordierite KW - Inverse Problems KW - Finite elements KW - Cohesive Elements KW - Young's modulus PY - 2019 AN - OPUS4-48926 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Eisentraut, Paul A1 - Hassanein, Yosri A1 - Elert, Anna Maria A1 - Braun, Ulrike T1 - Understanding degradation mechanisms of microplastics in environmental samples N2 - Im Vortrag wird die Problematik Mikroplastik eingeführt und ein Probenset aus dem Mittelmeer mit ersten Ergebnissen besprochen. Die Alterung von Polymeren im Umweltkontext sowie Möglichkeiten der Analyse von Polymeralterungsfortschritten werden diskutiert. Die thermoanalytische Methode mit Zersetzungsgasanalytik (TED-GC-MS) wird eingeführt und deren Einsatzmöglichkeiten in der Thematik umrissen. T2 - EuroMech Colloquium 607 Marine Aging of Polymers CY - Brest, France DA - 28.08.2019 KW - Microplastics KW - Tara Mediterranee KW - Polymer aging KW - TED-GC-MS PY - 2019 AN - OPUS4-49110 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute A1 - Kage, Daniel A1 - Weigert, Florian A1 - Martynenko, Irina A1 - Dhamo, Lorena A1 - Soares, J. X. T1 - Luminescent nanocrystals – Photophysics and applications for lifetime multiplexing N2 - Bioanalytical, diagnostic, and security applications require the fast and sensitive determination of a steadily increasing number of analytes or events in parallel in a broad variety of detection formats.[1,2] Ideal candidates for spectral encoding and multiplexing schemes are luminescent nanocrystals like semiconductor quantum dots (QDs), particularly Cd-containing II/VI QDs with their narrow and symmetric emission bands. With the availability of relatively simple and inexpensive instrumentation for time-resolved fluorescence measurements, similar strategies utilizing the compound-specific parameter fluorescence lifetime or fluorescence decay kinetics become increasingly attractive.[3-5] The potential of different types of QDs like II/VI, III/V and Cd-free ternary QDs such as AgInS (AIS) QDs for lifetime-based encoding and multiplexing has been, however, barely utilized, although the lifetimes of these nanocrystals cover a time windows which is barely accessible with other fluorophores. Here we present a brief insight into the photophysics of AIS QDs and show the potential of dye- and QD-encoded beads for lifetime-based encoding and detection schemes in conjunction with flow cytometry and fluorescence lifetime imaging microscopy T2 - Nanax 2019 CY - Hamburg, Germany DA - 16.09.2019 KW - Nano KW - Microparticle KW - Bead KW - Encoding KW - Lifetime KW - Multiplexing KW - Flow cytometry KW - Bead-based assay KW - Fluorescence KW - Dye KW - LT-FCM KW - Time-resolved flow cytometry KW - Method PY - 2019 AN - OPUS4-49039 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn A1 - Florian, Camilo A1 - Kirner, Sabrina V. A1 - Krüger, Jörg T1 - Femtosecond laser-induced periodic surface structures: from light localization to applications N2 - This presentation reviews the current state in the field of Laser-induced Periodic Surface Structures (LIPSS). These surface nanostructures are a universal phenomenon and can be generated on almost any material by irradiation with intense linearly polarized laser radiation. LIPSS are formed in a “self-ordered” way and are often accompanying material processing applications. They can be produced following a single-step process and enable surface functionalization through the adaption of optical, mechanical and chemical surface properties. Their structural sizes typically range from several micrometers down to less than 100 nanometers exhibiting a clear correlation with the polarization direction of the laser radiation. Various types of surface structures are classified, relevant control parameters are identified, and their material specific formation mechanisms are analyzed for different types of inorganic solids, i.e., metals, semiconductors, and dielectrics, through time-resolved optical experiments and theoretical simulations. Finally, technological applications featuring surface functionalization in the fields of optics, fluidics, medicine, and tribology are discussed. T2 - International Conference on Advanced Laser Technologies (ALT'19) CY - Prague, Czech Republic DA - 15.09.2019 KW - Laser-induced periodic surface structures, LIPSS KW - Femtosecond laser KW - Surface functionalization KW - Electromagnetic scattering PY - 2019 AN - OPUS4-49098 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Crasselt, Claudia A1 - Schmidt, Wolfram A1 - Sturm, Heinz T1 - Influence of rheology modifying admixtures on early hydration of cementitious suspensions N2 - The presence of polycarboxylate ether (PCE) based superplasticizers (SPs) has enormous influence on the early hydration of cement. C3A as the most reactive phase of Portland cement plays a significant role in early hydration reactions and affects the rheological performance. Therefore, this talk presents experimental results about the influence of delayed addition of PCEs on the Hydration of alite and C3A-gypsum pastes investigated by isothermal heat flow calorimetry. Complementary in-situ XRD was carried out on C3S and C3A-gypsum pastes to analyze hydration and phase changes related to the addition of PCE. Cement pastes with a delayed addition of PCE showed less retardation compared to simultaneous addition. The alteration caused by PCE is much more pronounced for C3A-gypsum mixes. With a delayed addition of SP, the hydration of C3A is less retarded or even accelerated. It is obvious that there is less retardation the later the addition of SP. Furthermore, the PCE alter the hydration of C3A when added delayed and exhibit changes in kinetics and Hydration rates. XRD results showed that more C3A is dissolved in the presence of PCE. Also, the gypsum depletion occurs earlier in the presence of PCE and even faster with delayed addition. Without PCE AFm starts to form just after the gypsum depletion. However, in the presence of PCE AFm already starts to form at the beginning of the hydration. Due to the faster gypsum depletion in the presence of PCE, also the transformation from ettringite into AFm begins earlier, but takes longer as without SP. T2 - 15th International Congress on the Chemistry of Cement CY - Prague, Czech Republic DA - 16.09.2019 KW - Cement KW - Alite KW - C3S KW - C3A KW - Early hydration KW - Polycarboxylate ether (PCE) KW - Delayed addition PY - 2019 AN - OPUS4-49103 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Le, Quynh Hoa A1 - Bäßler, Ralph A1 - Schiller, B.N A1 - Beck, M. A1 - Bettge, Dirk T1 - On the corrosion behaviour of CO2 injection pipe steels: Role of cement N2 - Carbon Capture and Storage (CCS) is identified as an excellent technology to reach the target of CO2 reduction. However, the safety issue and cost-effectiveness hinder the future of CCS. For the reliability and safety issues of injection wells, the corrosion resistance of the materials used needs to be determined. In this study, representative low-cost materials including carbon steel 1.8977 and low alloyed steel 1.7225 were investigated in simulated pore water at 333 K and under CO2 saturation condition to represent the worst-case scenario: CO2 diffusion and aquifer fluid penetration. These simulated pore waters were made from relevant cement powder to mimic the realistic casing-cement interface. Electrochemical studies were carried out using the pore water made of cement powder dissolved in water in comparison with those dissolved in synthetic aquifer fluid, to reveal the effect of cement as well as formation water on the steel performance. Two commercially available types of cement were investigated: Dyckerhoff Variodur® and Wollastonite. Variodur® is a cement containing high performance binder with ultra-fine blast furnace slag which can be used to produce high acid resistance concrete. On the other hand, Wollastonite is an emerging natural material mainly made of CaSiO3 which can be hardened by converting to CaCO3 during CO2 injection. The results showed the pH-reducing effect of CO2 on the simulated pore water/aquifer (from more than 10 to less than 5) leading to the active corrosion process that happened on both 1.8977 and 1.7225. Electrochemical characterization showed negative free corrosion potential and polarisation curves without passive behaviors. The tested coupons suffered from pitting corrosion, which was confirmed by surface analysis. Interestingly, basing on the pit depth measurements from the tested coupons and the hardness of cement powder, it is suggested that Variodur® performed better than Wollastonite in both aspects. The electrochemical data was compared to that resulted from exposure tests to give a recommendation on material selection for bore-hole construction. T2 - EUROCORR 2019 CY - Sevilla, Spain DA - 09.09.2019 KW - Carbon capture KW - Utilization, and storage (CCUS) technology KW - Corrosion KW - Carbon steel KW - Mortel KW - Crevice corrosion PY - 2019 AN - OPUS4-49105 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - von Oertzen, Alexander T1 - New Standardisation Tasks under the European Explosives Directive: Electronic Detonators, On-site Mixed Explosives N2 - Several decades have passed since the initial drafting of the European standards for explosives subject to European Directive 2014/28/EU, and this field as experienced some substantial technical innovations. While at the turn of the millenium the concept of electronic detonators had just been conceived, and it is mentioned in a Technical Specification, today electronic detonators exist in many variants, also regarding communication means between shotfirer and the detonating cap. Questions regarding safe functioning and prevention of inadvertent ignition have to be asked in a quite different way, where delicate electronic circuits are used, and where information is transmitted by radio waves. In addition, the safety of functioning is partly found in software components and the corresponding standards need to be reviewed thoroughly on these grounds. A different but in recent times more and more popular technology, is the on-site production of explosives, being mostly emulsion explosives, ANFO, or combined products. Also here software in the machinery is starting to play an important role. The on-site produced explosive must fulfil safety requirements and has to be, in addition, quality controlled. This cannot solely be left to the hopefully proper design of the software and machinery, but needs to be made accessible to verification. Since this area seems broader in approach, it is not going to be addressed by a new standard. The state of the art technology shall be described in a Technical Specification with a perspective from requirements of the above mentioned European Directive. T2 - EFEE 10th anniversary World Conference on Explosives and Blasting CY - Helsiniki, Finland DA - 15.09.2019 KW - Standardisation KW - Harmonised Standards KW - Technical Specification KW - Electronic Detonators KW - On-site mixed Explosives PY - 2019 AN - OPUS4-49106 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Frei, J. A1 - Biegler, M. A1 - Rethmeier, Michael T1 - Resistance spot welding under external load for evaluation of LME susceptibility of zinc coated advanced high strength steel sheets N2 - Some zinc coated advanced high strength steels (AHSS), under certain manufacturing conditions, are known to be prone to liquid metal embrittlement (LME) during resistance spot welding. LME is an undesired phenomenon, which can cause both surface and internal cracks in a spot weld, potentially influencing its strength. An effort is made to understand influencing factors of LME better, and evaluate geometry-material combinations regarding their LME susceptibility. Manufacturers benefit from such knowledge because it improves the processing security of the materials. The experimental procedure of welding under external load is performed with samples of multiple AHSS classes with strengths up to 1200 MPa, including dual phase, complex phase and TRIP steels. This way, externally applied tensile load values are determined, which cause liquid metal embrittlement in the samples to occur. In the future, finite element simulation of this procedure gives access to in-situ stress and strain values present during LME formation. The visualization improves the process understanding, while a quantification of local stresses and strains allows an assessment of specific welded geometries. T2 - ESDAD 2019 CY - Dusseldorf, Germany DA - 24.06.2019 KW - RSW KW - LME KW - Advanced high strength steel KW - Testing method KW - Zinc coated steel PY - 2019 AN - OPUS4-49079 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute A1 - Würth, Christian A1 - Frenzel, Florian A1 - Grauel, Bettina A1 - Nirmalananthan-Budau, Nithiya A1 - Pauli, Jutta A1 - Hoffmann, Katrin T1 - Photoluminescence at BAM – Photoluminescence at BAM – Photophysical Studies, Quantum Yield Measurements, Multiplexing Strategies, and Standards N2 - Photoluminescence applications in the life and material sciences require bright molecular and nanocrystalline emitters, stimuli-responsive optical probes, signal enhancement, multiplexing, and barcoding strategies and traceable methods to quantify the signal-relevant optical properties of luminescent materials at the ensemble and single molecule/particle level. In this context, current research at Division Biophotonics of BAM is presented ranging from dye and nanocrystal photophysics, absolute measurements of photoluminescence quantum yields in the UV/vis/NIR/SWIR, lifetime multiplexing, and the development of different types of fluorescence standards for validating optical-spectroscopic measurements. T2 - Institutskolloquium IPHT CY - Jena, Germany DA - 22.10.2019 KW - Surface group analysis KW - NIR KW - SWIR KW - Quantum dot KW - Lanthanide KW - Cleavable probe KW - Lifetime KW - Multiplexing KW - Sensor KW - Assay PY - 2019 AN - OPUS4-49360 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute A1 - Pauli, Jutta A1 - Würth, Christian A1 - Güttler, Arne A1 - Richter, Maria A1 - Schneider, Thomas T1 - Determining Photoluminescence Quantum Yields of Molecular and Nanocrystal Emitters in the UV/vis/NIR/SWIR N2 - The comparison of different emitter classes and the rational design of the next generation of molecular and nanoscale reporters require accurate and quantitative photo-luminescence measurements. This is of special importance for all photoluminescence applications in the life and material sciences and nanobiophotonics. In the following, procedures for the determination of the spectroscopic key parameter photoluminescence quantum yield, i.e., the number of emitted per absorbed photons, in the UV/vis/NIR/SWIR are presented including pitfalls and achievable uncertainties and material-specific effects related to certain emitter classes are addressed. T2 - Kolloqium National Center for Nanoscience and Technology CY - Peking, People's Republic of China DA - 18.10.2019 KW - Fluorescence KW - Quantum yield KW - Integrating sphere spectroscopy KW - Dye KW - Nanocrystal KW - NIR KW - SWIR KW - Quantum dot KW - Fluorescence standard KW - Uncertainty KW - Calibration PY - 2019 AN - OPUS4-49362 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Evans, Alexander A1 - Mohr, Gunther A1 - Hilgenberg, Kai A1 - Straße, Anne A1 - Gumenyuk, Andrey A1 - Winterkorn, René A1 - Pittner, Andreas A1 - Sommer, Konstantin A1 - Bettge, Dirk A1 - Kranzmann, Axel A1 - Nolze, Gert A1 - Avila, Luis A1 - Rehmer, Birgit A1 - Charmi, Amir A1 - Falkenberg, Rainer A1 - Skrotzki, Birgit A1 - Werner, Tiago A1 - Madia, Mauro A1 - Zerbst, Uwe A1 - Ulbricht, Alexander A1 - Sprengel, Maximilian A1 - Kromm, Arne A1 - Thiede, Tobias A1 - Bruno, Giovanni T1 - Ageing in additively manufactured metallic components: from powder to mechanical failure” an overview of the project agil N2 - An overview of the BAM funed Focus Area Materials Project "AGIL" will be presented. AGIL focussed on the stdiy of the ageing characteristics of additively manufactured austenitic stainless steel with a "powder to mechanical failure" Approach. Recent Highlights are presented and a perspective for future studies. T2 - Workshop on Additive Manufacturing CY - BAM, Berlin, Germany DA - 13.05.2019 KW - Residual stress KW - Additive Manufacturing KW - Non-destructive testing KW - Microstructure characterisation KW - Tensile testing KW - Fatigue KW - Crystal Plasticity Modelling KW - Crack propagation PY - 2019 AN - OPUS4-49823 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Avila, Luis A1 - Rehmer, Birgit A1 - Skrotzki, Birgit A1 - Graf, B. A1 - Rethmeier, Michael A1 - Ulbricht, Alexander T1 - Low cycle fatigue behavior and failure mechanisms of additively manufactured Ti-6Al-4V N2 - Despite of the significant advances in AM process optimization there is still a lack of experimental results and understanding regarding the mechanical behavior and microstructural evolution of AMparts, especially in loading conditions typical for safety-relevant applications e.g. in the aerospace or power engineering. Within the scope of the presented investigations, a characterization of the fatigue behavior of additively manufactured Ti-6Al-4V in the low cycle fatigue regime was carried out in the range of 0.3 to 1.0 % strain amplitude at room temperature, 250°C and 400°C. The Ti-6Al-4V specimens are machined out of lean cylindrical rods, which were fabricated using powder laser metal deposition (LMD) with an improved build-up strategy. The improved strategy incorporates variable track overlap ratios to achieve a constant growth in the shell and core area. The low-cycle-fatigue behavior is described based on cyclic deformation curves and strain-based fatigue life curves. The lifetimes are fitted based on the Manson-Coffin-Basquin relationship. A characterization of the microstructure and the Lack-of-Fusion (LoF)-defect-structure in the as-built state is performed using optical light microscopy and high-resolution computed tomography (CT) respectively. The failure mechanism under loading is described in terms of LoF-defects-evolution and crack growth mechanism based on an interrupted LCF test with selected test parameters. After failure, scanning electron microscopy, digital and optical light microscopy and CT are used to describe the failure mechanisms both in the longitudinal direction and in the cross section of the specimens. The fatigue lives obtained are comparable with results from previous related studies and are shorter than those of traditionally manufactured (wrought) Ti-6Al-4V. In this study new experimental data and understanding of the mechanical behavior under application-relevant loading conditions (high temperature, cyclic plasticity) is gained. Furthermore, a better understanding of the role of LoFdefects and AM-typical microstructural features on the failure mechanism of LMD Ti-6Al-4V is achieved. T2 - First European Conference on Structural Integrity of Additively Manufactured Materials (ESIAM19) CY - Trondheim, Norway DA - 09.09.2019 KW - High Temperature Testing KW - Titanium KW - Ti-6Al-4V KW - Additive Manufacturing KW - Computed Tomography KW - Microstructure KW - Tensile Properties KW - Low Cycle Fatigue PY - 2019 AN - OPUS4-49492 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schaupp, Thomas A1 - Yahyaoui, Hamza A1 - Rhode, Michael A1 - Kannengießer, Thomas T1 - Effect of weld penetration depth on hydrogen-assisted cracking of high-strength structural steels N2 - The need for steels with highest mechanical properties is a result of the increasing demands for energy and resource efficiency. In this context, high-strength structural (HSS) steels are used in machine, steel and crane construction with yield strength up to 960 MPa. However, welding of HSS steels requires profound knowledge of three factors in terms of avoidance of hydrogen-assisted cracking (HAC): the interaction of (1) microstructure, (2) local stress/strain and (3) local hydrogen concentration. In addition to the three main factors, the used weld-arc process is also important for the performance of the welded joint, especially when using modern arc variants. In the past, the conventional transitional arc process (Conv. A) was mainly used for welding of HSS grades. In the past decade, the so-called modified spray arc process (Mod. SA) has been used increasingly for welding production. This modified process enables reduced seam opening angles with increased deposition rates compared to the conventional process. Economic benefits of using this arc type are: a reduced number of necessary weld beads and a lower weld seam volume, which result in decreased total welding time and costs. Nonetheless, investigations on a high-strength S960QL showed significantly higher hydrogen concentrations in the weld metal at a reduced seam opening angle with Mod. SA. This indicates an increased susceptibility of the welded component to HAC. Hence, existing recommendations on HAC-avoidance cannot be transferred directly to the Mod. SA-process. In the present study, the susceptibility to HAC of the HSS steel S960QL with same type of filler material was investigated. For that purpose, both Conv. A and Mod. SA were used with same heat input at different deposition rates. For assessment of the HAC susceptibility, the externally loaded implant test was used. Both conducted test series with Conv. A and Mod. SA showed similar crack critical stress of about 280 MPa. Below this value, no delayed fracture appeared. The welds with Mod. SA showed higher hydrogen concentrations. The fracture occurred in the heat-affected zone (HAZ) or in the weld metal (WM). However, the test series with Mod. SA showed a significant extension of the time to failure of several hours compared to tests carried out with Conv. A. T2 - 72nd IIW Annual Assembly and International Conference: Commission II-A CY - Bratislava, Slovakia DA - 07.07.2019 KW - Hydrogen KW - Implant test KW - High-strength steels KW - Fractography PY - 2019 AN - OPUS4-48462 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Artinov, Antoni A1 - Karkhin, Victor A1 - Khomich, P. A1 - Bachmann, Marcel A1 - Rethmeier, Michael T1 - Assessment of welding thermal cycles by boundary element method N2 - A numerical framework simulation of the steady-state thermal behaviour in keyhole mode welding has been developed. It is based on the equivalent heat source concept and consists of two parts: computational thermo-fluid dynamics and heat conduction. The solution of the thermo-fluid dynamics problem by the finite element method for a bounded domain results in a weld pool interface geometry being the input data for a subsequent heat conduction problem solved for a workpiece by proposed boundary element method. The main physical phenomena, such as keyhole shape, thermo-capillary and natural convection and temperaturedependent material properties are taken into consideration. The developed technique is applied to complete-penetration keyhole laser beam welding of a 15 mm thick low-alloyed steel plate at a welding speed of 33 mm/s and a laser power of 18 kW. The fluid flow of the molten metal has a strong influence on the weld pool geometry. The thermo-capillary convection is responsible for an increase of the weld pool size near the plate surfaces and a bulge formation near the plate middle plane. The numerical and experimental molten pools, cross-sectional weld dimensions and thermal cycles of the heat affected zone are in close agreement. T2 - 72nd IIW Annual Assembly and International Conference CY - Bratislava, Slovakia DA - 07.07.2019 KW - Numerical simulation KW - Boundary element method KW - Themral cycles KW - Keyhole mode welding KW - Bulging PY - 2019 AN - OPUS4-48467 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Li, Wei T1 - Fatigue on carbon fiber reinforced composite under thermal cycling: Progress in the microscopic experiment N2 - Fiber-reinforced-polymers (FRPs) are in current research focus in the lightweight construction industry, because of their extraordinary characteristics (stiffness and strength-to-density relation). The structure of polymer matrix and the interaction with reinforcement are crucial for optimization of the mechanical and thermal properties of FRPs. Due to the macromolecular chain structure, the mechanical properties of a polymer strongly vary with temperature: Below the glass transition, the chain segments of a polymer are “frozen”. Regarding fracture, the total changed energy during fracture if only dissipates for the generation of the new surfaces. However, in the region of the glass transition, the polymer chain segments start to get “unfrozen”, and the energy is not only required for generating new surfaces, but also for irreversibly deformation. This irreversible deformation is affected by the global temperature and the local temperature near the crack tip, which is affected by the local strain rate and crack propagation velocity. Hence, in this research project, the irreversible deformation of neat and reinforced polymers will be controlled by changing the global temperature as well as the local temperature. With using different fracture experiments, the amount of energy required for creating new surfaces and for the irreversible deformation will be separated. In this presentation, I summarized of the first 15 months the whole project. In this period, the basic crack propagation theory for neat polymers is established and the special fracture experiment sample is prepared and tested at room temperature. In addition, the model of the specimen is first established. T2 - Doktorandenseminar von Abteilung 5 CY - Berlin, Germany DA - 25.01.2019 KW - Crack Propagation KW - Polymer PY - 2019 AN - OPUS4-48473 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Duwe, M. A1 - Fischer, Daniel A1 - Quast, J.-H. A1 - Schneider, S. A1 - Beck, Uwe T1 - Curved-surface metrology by imaging Mueller-matrix ellipsometry N2 - Outline - maging ellipsometry: oncept and setup - Basic theory: ellipsometry on tilted/curved surfaces - Geometric considerations - Tilt-induced cross-polarization - Application: coating analysis on microlensarray - Mueller-Matrix Imaging - Conversion to Delta-Psi Image - Layer-thickness of ITO coating T2 - 8th International conference on spectroscopic CY - Barcelona, Spain DA - 26.05.2019 KW - Spectroscopic Imaging KW - Mueller-Matrix Ellipsometry KW - Curved surfaces PY - 2019 AN - OPUS4-48366 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rütter, H. A1 - Le, Quynh Hoa A1 - Knauer, S. A1 - Bettge, Dirk A1 - Kranzmann, Axel T1 - Combining CO2 streams from different emitters ‐ a challenge for pipeline transportation N2 - Depending on the CO2 generating and the capture process as well as on consecutive purification steps applied, CO2 streams from different emitters may differ in their composition. When CO2 streams with different compositions are fed into a larger pipeline network, there are several aspects that must be considered: i) chemical reactions, such as acid formation, may occur within the joint CO2 stream; ii) there may be a variation of mass flow rate and CO2 stream composition within the pipeline network if the feed-in behavior of different CO2 sources changes with time. Potential impacts of changing CO2 stream compositions and mass flow rates in CCS cluster systems were investigated in the collaborative project "CLUSTER" (see also www.bgr.bund.de/CLUSTER). In this presentation, we focus on the experimental investigations of formation and condensation of strong acids and their impacts on the corrosion of pipeline steels. When SO2, NO2, O2 and H2O are present simultaneously in CO2 streams chemical cross-reactions may occur leading to the formation of strong acids such as sulfuric and nitric acid. To prevent this acid formation the concentration of at least one of these four impurities must be kept very low (e.g., Rütters et al., 2016). At temperatures below the acid dew point temperature, acids will condense, e.g., on pipeline steel surfaces. In turn, these acid condensates may trigger steel corrosion. To better understand the process of acid formation and condensation and its implications for steel corrosion, exposure tests were performed on pipeline steel X70 in dense CO2 with varying SO2, NO2 and O2 concentration under high pressure and at 278 K in an observable autoclave, in which water was added as droplets or as vapor. Further, electrochemical tests were carried out with X70 specimens immersed in 500 mL CO2-saturated synthetic condensate solution or in droplets of the same solution on the specimen’s surface. Depending on impurity concentrations in the CO2 streams, condensates consisting of different relative amounts of nitric and sulfuric acid were formed. In condensates containing both nitric and sulfuric acid, corrosion rates were higher than the sum of those of the individual acids. In addition, corrosion products and forms depended on the condensate composition. Investigations of water droplets on steel surfaces in impurity-containing dense-phase CO2 revealed the diffusion of SO2 and NO2, followed by cross-reactions forming corresponding acids. An increase in droplet size (from 1 to 5 µl) lead to higher corrosion rates. However, in comparison to measurements in bulk solution, corrosion reactions in droplets resulted in thick, high-resistance corrosion products and observed droplet corrosion rates were significantly lower. In addition, the possibility of acid droplet formation and growth in impure liquid CO2 is influenced by the wetting behavior of the acid droplet on the steel surface. Thus, the contact angle between a water droplet and the surface steel specimens in a CO2 atmosphere was investigated in a high pressure view cell following the sessile drop method. The contact angle wasand found to be larger at higher CO2 pressures (studied from 5 to 20 MPa) and at higher temperatures (e.g. 278 K to 333 K). Further, measured contact angles were larger on rough than on smooth metal surfaces. In addition, acid formation reduced the contact angle, i.e. lead to better wetting, thereby stimulating condensation that was followed by a corrosion process. These detailed insights on the complex interplay of acid formation, condensation, wetting behavior and corrosion allow a better assessment of material suitability for pipeline transportation of impure CO2 streams T2 - TCCS-10 The 10th Trondheim Conference on Carbon Capture, Transport and Storage CY - Trondheim, Norway DA - 17.06.2019 KW - arbon capture KW - utilization, and storage (CCUS) technology KW - corrosion KW - condensate KW - electrochemical characterization KW - pitting corrosion KW - impurities KW - carbon steel PY - 2019 UR - https://www.sintef.no/globalassets/project/tccs-10/dokumenter/tccs10---book-of-abstracts.pdf AN - OPUS4-48369 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Beck, Uwe A1 - Hielscher-Hofinger, Stefan A1 - Lange, Thorid A1 - Stockmann, Jörg M. A1 - Weise, Matthias A1 - Rietz, U. A1 - Lerche, D. T1 - Centrifugal force meets materials testing – analytical centrifuge as multipurpose tool for tensile and compressive stress testing N2 - Up until several years ago, tensile and compressive tests have been exclusively carried out as single-sample tests within a tensile, hardness or universal testing machine. The availability of centrifuge technology changed this situation in 2013 in several ways because centrifugal force is used as testing force within a rotational reference frame. Firstly, multiple-sample strength testing became feasible for both tensile load condi-tions, e.g. determination of composite, bonding or adhesive strength, and compressive load conditions, e.g. hardness, compressibility and compactibility. Secondly, there is no need for a two-sided sample clamping and double-cardanic suspensions as samples are simply inserted using a one-sided sample support. Thirdly, shear forces can be avoided by means of guiding sleeves which steer test stamps acting as mass bodies for either tensile or compressive testing. Fourthly, up to eight samples can be tested under identical conditions within a very short period of time, typically within 15 minutes including sample loading and unloading. Hence, either a reliable statistics (of identical samples) or a ranking (of different samples) can be derived from one test run. The bench-top test system is described in detail and demonstrated that centrifugal force acts as testing force in an appropriate way because Euler and Coriolis force do not affect the testing results. Examples for both tensile strength testing, i.e. bonding strength of adhesives-bonded joints and adhesive strength of coatings, and compres-sive strength testing, i.e. Vickers-, Brinell- and ball indentation hardness and deter-mination of spring constants, are presented, discussed and compared with conven-tional tests within tensile, hardness or universal testing machines. At present, a maximum testing force of 6.5 kN can be realized which results at test stamp diameters of 5 mm, 7 mm, and 10 mm in tensile or compressive stress values of 80 MPa, 160 MPa, and 320 MPa. For tensile strength, this is already beyond bonding strength of cold- and warm-curing adhesives. Moreover, centrifuge technology is compliant to standards such as EN 15870, EN ISO 4624, EN ISO 6506/6507 and VDI/VDE 2616. Programmable test cycles allow both short-term stress and log-term fatigue tests. Based on a variety of examples of surface and bonding technology, applications in both fields R&D and QC are presented. Meanwhile, centrifuge technology is also accredited according to DIN EN ISO/IEC 17025. T2 - Intermationa Conference Dispersion Analysis & Materials Testing CY - Berlin, Germany DA - 22.05.2019 KW - Centrifugal Force KW - Compressive Stress KW - Tensile Stress PY - 2019 AN - OPUS4-48310 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -