TY - CONF A1 - Falkenhagen, Jana T1 - Copolymer structure elucidation by multidimensional techniques with focus on UPLC x ESI-TOF-MS N2 - Structure elucidation of complex synthetic copolymers still represents a challenge. An one-dimensional separation technique cannot give the answer to the question: What are the molar mass distribution (MMD), the functionality distribution (FTD), the chemical composition distribution (CCD), the monomer sequence distribution (MSD), the topology differences within a single broad distributed polymer sample? Since the first LC/ ESI-MS experiment of the Nobel prize winner John B. Fenn in 1984, the coupling of liquid chromatographic to mass spectrometric techniques gained a continuous rapid development. Often the deficiencies of stand-alone methods can be bridged. LC, blind to structural information needs mass spectrometry as one of the most powerful detectors able to give detailed information on e.g. the repeat units, functionalization or copolymer composition of the chromatographic separated constituents. A separation prior to MS reduces radical the dispersity which is one of the reasons for failing of MS. Also problems with different ionization probabilities in complex mixtures can partly be overcame. Different LC separation techniques as size exclusion chromatography (SEC), liquid adsorption chromatography (LAC), liquid chromatography at critical conditions (LCCC) and gradient elution liquid chromatography (GELC) combined with Matrix assisted Laser Desorption Ionization (MALDI) respectively Electrospray Ionization (ESI) Time of Flight (TOF) mass spectrometry are able to give information which otherwise are completely inaccessible. In some cases CID tandem mass spectrometry is applied. Fragmentation of suitable precursor ions resulted in typical fragment ion patterns. This technique enables an additional information on e.g. sequences, structural defects and topology of complex polymer mixtures. Herein a new approach is demonstrated to provide evidence of different functionalities and short block sequences in statistical EO-PO copolymers. Furthermore silsesquioxane mixtures and Polyglycerols are investigated concerning occurring topology effects. T2 - 253rd ACS National Meeting CY - San Francisco, CA, USA DA - 02.04.2017 KW - Copolymer KW - Microstructure KW - Liquid chromatography KW - Mass spectrometry PY - 2017 AN - OPUS4-43372 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Cabeza, Sandra A1 - Thiede, Tobias A1 - Mishurova, Tatiana A1 - Nadammal, Naresh A1 - Kromm, Arne A1 - Bruno, Giovanni T1 - Development of residual stresses in IN718 parts obtained by SLM N2 - Additive Manufacturing by Selective Laser Melting (SLM) offers ample scope for producing geometrically complex parts as compared to the traditional subtractive manufacturing strategies. However, the residual stresses (RS) developed during the processing can reduce the load bearing capacity as well as induce unwanted distortion, limiting the application of SLM parts. In the present work, residual stresses in additivly manufactured IN718 part were analised by means of neutron diffraction and synchrotron X-ray diffraction. T2 - ISAM 2017 CY - Dresden, Germany DA - 07.02.2017 KW - Additive manufacturing KW - Residual stress KW - Inconel 718 KW - Netron diffraction KW - Microstructure PY - 2017 AN - OPUS4-39139 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Huang, S. G. A1 - Vleugels, J. A1 - Mohrbacher, H. A1 - Woydt, Mathias T1 - Effect of carbon content on the microstructure and mechanical properties of NbC-Ni based cermets N2 - The aim of this work was to correlate the carbon content in NbC-Ni starting powders with the resulting microstructure, hardness and fracture toughness of Ni-bonded NbC cermets. T2 - 19. Plansee Seminar CY - Reutte, Austria DA - 29.05.2017 KW - Cermet KW - Liquid phase sintering KW - Microstructure KW - Hardness KW - Carbon PY - 2017 AN - OPUS4-40647 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Huang, S. G. A1 - Vleugels, J. A1 - Mohrbacher, H. A1 - Woydt, Mathias T1 - Effect of carbon content on the microstructure and mechanical properties of NbC-Ni based cermets T2 - International Conference on Refractory Metals and Hard Materials N2 - The aim of this work was to correlate the carbon content in NbC-Ni starting powders with the resulting microstructure, hardness and fracture toughness of Ni-bonded NbC cermets. T2 - 19. Plansee Seminar CY - Reutte, Austria DA - 29.05.2017 KW - Cermet KW - Liquid phase sintering KW - Microstructure KW - Hardness KW - Carbon PY - 2017 SP - HM 109/1 EP - HM 109/11 AN - OPUS4-40595 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stegemann, Robert A1 - Cabeza, Sandra A1 - Pelkner, Matthias A1 - Lyamkin, Viktor A1 - Sonntag, Nadja A1 - Bruno, Giovanni A1 - Skrotzki, Birgit A1 - Kreutzbruck, Marc T1 - Evaluation of high spatial resolution imaging of magnetic stray fields for early damage detection T2 - AIP Conference Proceeding N2 - The paper discusses the evaluation of elastic and plastic strain states in two low-carbon steels of the same steel group with high spatial resolution GMR (giant magneto resistance) sensors. The residual stress distributions of tungsten inert gas welded plates were determined by means of neutron diffraction as a reference. The normal component of local residual magnetic stray fields arise in the vicinity of the positions of maximum stress. The experiments performed on flat tensile specimen indicate that the boundaries of plastic deformations are a source of stray fields. The spatial variations of magnetic stray fields for both the weld and the tensile samples are in the order of the earths magnetic field. T2 - 43rd Annual Review of Progress in Quantitative Nondestructive Evaluation, Volume 36 CY - Atlanta, Georgia, USA DA - 17.07.2016 KW - Plastic deformation KW - GMR KW - Neutron diffraction KW - Residual stress KW - Microstructure KW - Low carbon steel KW - TIG weld PY - 2017 SN - 978-0-7354-1474-7 DO - https://doi.org/10.1063/1.4974688 SN - 0094-243X VL - 1806 IS - 1 SP - Article UNSP 110010-1 EP - 10 PB - AIP Publishing CY - Melville, NY 11747 AN - OPUS4-39279 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rhode, Michael A1 - Mente, Tobias A1 - Steppan, Enrico A1 - Steger, Joerg A1 - Kannengießer, Thomas T1 - Hydrogen trapping in T24 steel weld joints - microstructure influence vs. experimental design effect on activation energy for diffusion N2 - In general, hydrogen assisted cracking is a result of a critical combination of local microstructure, mechanical load and hydrogen concentration. In that connection, welded microstructures of low-alloyed creep-resistant steels can show different hydrogen trapping kinetics. That influences the adsorbed hydrogen concentration as well as the diffusion itself in terms of moderate or strong trapping. A common approach to describe trapping is by the activation energy that is necessary to release hydrogen from a specific trap site. In the present study, T24 base material and weld metal were investigated. For that purpose, electrochemically hydrogen charged specimens were analyzed by thermal desorption analysis(TDA) with linear heating using a mass spectrometer. The results showed a microstructure effect on hydrogen trapping kinetics at elevated temperatures. Additionally, it is necessary to monitor the specimen temperature. A comparison between idealized temperature profile and real specimen temperature showed that the calculated activation energy varied up to a factor of two. Thus, the assigned trap character(moderate or strong) changed. In case of high temperature peaks, this effect could be more important compared to the microstructure effect itself. T2 - 70th IIW Annual Assembly, Commission II-A CY - Shanghai, People's Republic of China DA - 25.06.2017 KW - Creep resisting materials KW - Welding KW - Hydrogen diffusion KW - Thermal desorption analysis KW - Microstructure KW - Experimental design PY - 2017 AN - OPUS4-40954 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thiede, Tobias A1 - Mishurova, Tatiana A1 - Cabeza, S. A1 - Nadammal, Naresh A1 - Bode, Johannes A1 - Kromm, Arne A1 - Haberland, C. A1 - Bruno, Giovanni T1 - Influence of deposition hatch length on residual stress in selective laser melted Inconel 718 N2 - Additive Manufacturing (AM) by Selective Laser Melting (SLM) offers ample scope for producing geometrically complex parts in comparison to the traditional subtractive manufacturing strategies. Developing during the manufacturing process, residual stresses may limit the application of SLM parts by reducing the load bearing capacity as well as induce unwanted distortion depending on the boundary conditions specified in manufacturing. The present study aims to evaluate the bulk residual stresses in SLM parts by using neutron diffraction measurements performed at E3 line -BER II neutron reactor- of Helmholtz-Zentrum für Materialien und Energie (HZB) Berlin. Together with microstructure characterization and distortion measurements, it is possible to describe the stress state throughout the whole sample. The sample was measured in as-build condition (on a build plate) and after releasing from the build plate. The used material is the nickel based superalloy 718. This alloy is widely used in aerospace and chemical industries due to its superior corrosion and heat resistant properties. Obtained results indicated different residual stress states for each of the transversal, longitudinal and normal component. The normal and transversal component exhibits a rather compressive behavior while the longitudinal was tensile in the center part of the sample and became compressive towards the tip. As expected, the absolute values of all stress components decreased after releasing the sample from the building plate. A surface scan utilizing a coordinate-measuring machine (CMM) allowed us to present top surface distortion before and after releasing. The top surface showed a distortion around ±80µm after releasing. Microstructure evolution in the scanning-building cross-section is largely dominated by columnar grains. In addition, many small random orientated grains are prominent in the regions of a laser overlap during SLM. In summary, for the sample of superalloy 718 manufactured by SLM, a small distortion occurred when removing the sample from the build plate whereby the residual stress state decreases. Moreover, the observed columnar grains in the building direction could give a reason for the lowest stress values in that normal direction. However, the most important parameter controlling the residual stresses is the temperature gradient. Hence, future investigations are planned for a different scan strategy to distribute the laser impact in a more homogenous manner. T2 - HZB User Meeting 2017 CY - Berlin, Germany DA - 15.12.2017 KW - AM KW - SLM KW - IN 718 KW - Neutron diffraction KW - Residual stress KW - Hatch length KW - Microstructure PY - 2017 AN - OPUS4-43475 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rockenhäuser, Christian A1 - Schriever, Sina A1 - Skrotzki, Birgit ED - Panfilov, Peter ED - Kodzhaspirov, Georgii T1 - Microstructural evolution during creep of Al-alloy 2618A T2 - Proceedings Creep 2017 N2 - The aluminum alloy 2618A is an Al-Cu-Mg alloy with additions of Fe and Ni, which was designed for long-term operation at elevated temperature in transportation and aerospace industries. Typical applications include aircraft parts and structures (sheet material) or engine components such as turbo charger centrifugal compressor wheels (forged material). Such components are subjected to prolonged aging during service, (e.g. 50 000 h) at temperatures which are close to their age hardening temperature (ca. 190 °C). The microstructural evolution during creep exposure is studied. T2 - Creep 2017 CY - St. Petersburg, Russia DA - 19.07.2017 KW - Creep KW - Microstructure KW - Coarsening KW - TEM PY - 2017 SN - 978-5-7422-5799-8 SP - 80 EP - 81 PB - SpbPU Publisher CY - St. Petersburg, Russia AN - OPUS4-40750 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Skrotzki, Birgit A1 - Rockenhäuser, Christian A1 - Schriever, Sina T1 - Microstructural Evolution during Creep of Al-Alloy 2618A N2 - The aluminum alloy 2618A is an Al-Cu-Mg alloy with additions of Fe and Ni, which was designed for long-term operation at elevated temperature in transportation and aerospace industries. Typical applications include aircraft parts and structures (sheet material) or engine components such as turbo charger centrifugal compressor wheels (forged material). Such components are subjected to prolonged aging during service, (e.g. 50 000 h) at temperatures which are close to their age hardening temperature (ca. 190 °C). The microstructural evolution was investigated. T2 - Creep 2017 CY - St. Petersburg, Russia DA - 18.06.2017 KW - Creep KW - Microstructure KW - Coarsening KW - TEM PY - 2017 AN - OPUS4-40756 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fu, B. A1 - Shen, J. A1 - Suhuddin, U. A1 - Su, H. A1 - dos Santos, J. A1 - Rethmeier, Michael T1 - Microstructure and mechanical properties of a modified refill friction stir spot welds of AM50 magnesium alloy T2 - WSE & CAWE 2017 N2 - Magnesium (Mg) alloys have attracted much attention due to their merits of meeting requirements of lightweight, energy-efficient and environmental friendly engineering. In this study, a modified refill friction stir spot welding (refill-FSSW) method is proposed to weid AMSO Mg alloy, in which pin and sleeve rotate at different states. Effects of process parameters on the microstructure, material flow, and mechanical properties of welds were studied. Results showed that, the modified refill-FSSW technology could enhance the intennixing of material by changing the flow state. Lap shear strength of welds could be significantly improved with changed failure modes. The modified refill FSSW technology is a competitive welding method for Mg alloy. T2 - 7th International Conference on Welding Science and Engineering in conjunction with 3rd International Symposium on Computer-Aided Welding Engineering CY - Jinan, China DA - 18.10.2017 KW - Refill friction stir spot welding KW - Friction spot welding KW - Magnesium KW - Microstructure KW - Mechanical properties PY - 2017 SP - 203 EP - 206 AN - OPUS4-43234 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -