TY - JOUR A1 - Kömmling, Anja A1 - Chatzigiannakis, E. A1 - Beckmann, Jörg A1 - Wachtendorf, Volker A1 - von der Ehe, Kerstin A1 - Braun, Ulrike A1 - Jaunich, Matthias A1 - Schade, U. A1 - Wolff, Dietmar T1 - Discoloration Effects of High-Dose gamma-Irradiation and Long-Term Thermal Aging of (U) HMW-PE N2 - Two polyethylene types with ultra-high (UHMWPE) and high molecular weight (HMW-PE) used as neutron radiation shielding materials in casks for radioactive waste were irradiated with doses up to 600 kGy using a 60Co gammasource. Subsequently, thermal aging at 125∘C was applied for up to one year. Degradation effects in the materials were characterized using colorimetry, UV-Visspectroscopy, IR spectroscopy, and DSC. Both materials exhibited a yellowing upon irradiation.The discoloration of UHMW-PE disappeared again after thermal aging.Therefore, the yellowing is assumed to originate fromannealable color centers in the formof free radicals that are trapped in the crystalline regions of the polymer and recombine at elevated temperatures. For the antioxidantcontaining HMWPE, yellowing was observed after both irradiation and thermal aging. The color change was correlated mainly to decomposition products of the antioxidant in addition to trapped radicals as in UHMW-PE. Additionally, black spots appeared after thermal aging of HMW-PE. KW - Irradiation KW - UHMWPE KW - Colour center KW - Yellowness index PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-423992 DO - https://doi.org/10.1155/2017/1362491 SN - 1687-9422 VL - 2017 IS - Article ID 1362491 SP - 1 EP - 10 PB - Hindawi AN - OPUS4-42399 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Klingelhoeffer, Hellmuth A1 - Aegerter, J. A1 - Scherm, T. A1 - Schenuit, E. A1 - Sotheran, S. A1 - Loveday, M. A1 - Bosch, P. A1 - Bloching, H. A1 - Olbricht, Jürgen A1 - McEnteggart, I. T1 - Discussion on "Analysis on the issues in ISO 6892-1 and TENSTAND WP4 report based on the data of confirm tests by 21 laboratories" N2 - The authors, Li et al., of the paper entitled “Analysis on the Issues in ISO 6892-1 and TENSTAND WP4 Report Based on Data to Confirm Tests by 21 Laboratories” (J. Test. Eval. DOI: 10.1520/JTE20150479 (online only)) have expressed views that the authors of this rebuttal believe to be based on fundamental misunderstandings and misinterpretations of the tensile testing standard ISO 6892-1:2009, ISO 6892-1:2016, and its former versions, thus leading to erroneous conclusions. This refutation is intended to clarify the understanding of ISO 6892-1 and to address the misunderstandings and the misinterpretations of the authors of the paper. The present standard ISO 6892-1:2016 has a long history dating back to the 1970s. At that time, the tensile testing procedure was standardized on the National and International scale in parallel. To understand the present standard, the knowledge of the history helps to understand the background of details of the testing procedure implemented today. The history of the tensile testing standard has been discussed extensively during the annual international standardization meeting of ISO committee TC 164 SC1 for the last few years, at which some of the authors of the Li et al. paper attended. The authors continue to disagree with facts that were agreed by the consortium of the European research project TENSTAND and by the present international experts involved in ISO TC 164 SC1. It appears that the principal objective of the authors regarding their present publication was to increase the testing speed during tensile testing. However, the international standardization community has previously declined similar proposals by some of the authors. Many arguments presented by Li et al. were thus refuted. The conclusions of their paper are misleading and the international standardization community for tensile testing refused to revise the present standard, ISO 6892-1 (2016), according the authors’ proposals. KW - Tensile testing procedure KW - ISO 6892-1 KW - TENSTAND WP4 Final Report PY - 2017 DO - https://doi.org/10.1520/JTE20160526 SN - 0090-3973 SN - 1945-7553 VL - 45 IS - 3 SP - 1105 EP - 1114 PB - ASTM International CY - West Conshohocken, PA, USA AN - OPUS4-40267 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Klingelhöffer, Hellmuth A1 - Aegerter, J. A1 - Scherm, T. A1 - Schenuit, E. A1 - Sotheran, S. A1 - Loveday, M. A1 - Bosch, P. A1 - Bloching, H. A1 - Olbricht, Jürgen A1 - McEnteggart, I. T1 - Discussion on “Analysis on the issues in ISO 6892-1 and TENSTAND WP4 report based on the data of confirm tests by 21 laboratories” by H. Li, X. Zhou, J. Shen, and D. Luo. The regular article was published in journal of Testing and Evaluation, Vol. 45, No. 3, 2017, pp. 723–731, doi:10.1520/ JTE20150479. ISSN 0090-3973 N2 - The authors, Li et al., of the paper entitled “Analysis on the Issues in ISO 6892-1 and TENSTAND WP4 Report Based on Data to Confirm Tests by 21 Laboratories” (J. Test. Eval. DOI: 10.1520/JTE20150479 (online only)) have expressed views that the authors of this rebuttal believe to be based on fundamental misunderstandings and misinterpretations of the tensile testing standard ISO 6892-1:2009, ISO 6892-1:2016, and its former versions, thus leading to erroneous conclusions. This refutation is intended to clarify the understanding of ISO 6892-1 and to address the misunderstandings and the misinterpretations of the authors of the paper. The present standard ISO 6892-1:2016 has a long history dating back to the 1970s. At that time, the tensile testing procedure was standardized on the National and International scale in parallel. To understand the present standard, the knowledge of the history helps to understand the background of details of the testing procedure implemented today. The history of the tensile testing standard has been discussed extensively during the annual international standardization meeting of ISO committee TC 164 SC1 for the last few years, at which some of the authors of the Li et al. paper attended. The authors continue to disagree with facts that were agreed by the consortium of the European research project TENSTAND and by the present international experts involved in ISO TC 164 SC1. It appears that the principal objective of the authors regarding their present publication was to increase the testing speed during tensile testing. However, the international standardization community has previously declined similar proposals by some of the authors. Many Arguments presented by Li et al. were thus refuted. The conclusions of their paper are misleading and the international standardization community for tensile testing refused to revise the present standard, ISO 6892-1 (2016), according the authors’ proposals. KW - Tnsile testing KW - ISO 6892-1 KW - TENSTAND WP4 Report PY - 2017 UR - www.astm.org DO - https://doi.org/10.1520/JTE20160526 SN - 0090-3973 VL - 45 IS - 3 SP - 1105 EP - 1114 PB - ASTM CY - West Conshohocken, PA, USA AN - OPUS4-46690 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bender, P A1 - Balceris, C. A1 - Ludwig, F A1 - Posth, O A1 - Bogart, L. K. A1 - Szczerba, Wojciech A1 - Castro, A A1 - Nilsson, L A1 - Costo, R A1 - Gavilan, H A1 - Gonzalez-Alonso, D A1 - de Pedro, I A1 - Barquin, L. F. A1 - Johansson, C T1 - Distribution functions of magnetic nanoparticles determined by a numerical inversion method N2 - In the present study, we applied a regularized inversion method to extract the particle size, magnetic moment and relaxation-time distribution of magnetic nanoparticles from small-angle x-ray scattering (SAXS), DC magnetization (DCM) and AC susceptibility (ACS) measurements. For the measurements the particles were colloidally dispersed in water. At first approximation the particles could be assumed to be spherically shaped and homogeneously magnetized single-domain particles. As model functions for the inversion, we used the particle form factor of a sphere (SAXS), the Langevin function (DCM) and the Debye model (ACS). The extracted distributions exhibited features/peaks that could be distinctly attributed to the individually dispersed and non-interacting nanoparticles. Further analysis of these peaks enabled, in combination with a prior characterization of the particle ensemble by electron microscopy and dynamic light scattering, a detailed structural and magnetic characterization of the particles. Additionally, all three extracted distributions featured peaks, which indicated deviations of the scattering (SAXS), magnetization (DCM) or relaxation (ACS) behavior from the one expected for individually dispersed, homogeneously magnetized nanoparticles. These deviations could be mainly attributed to partial agglomeration (SAXS, DCM, ACS), uncorrelated surface spins (DCM) and/or intra-well relaxation processes (ACS). The main advantage of the numerical inversion method is that no ad hoc assumptions regarding the line shape of the extracted distribution functions are required, which enabled the detection of these contributions. We highlighted this by comparing the results with the results obtained by standard model fits, where the functional form of the distributions was a priori assumed to be log-normal shaped. KW - SAXS KW - Small-angle X-ray scattering KW - Nanoparticle PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-429373 DO - https://doi.org/10.1088/1367-2630/aa73b4 SN - 1367-2630 VL - 19 SP - 073012, 1 EP - 073012, 19 PB - IOP Publ. Ltd. AN - OPUS4-42937 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wilke, Manuel A1 - Bach, S. A1 - Gorelik, T. A1 - Kolb, U. A1 - Tremel, W. A1 - Emmerling, Franziska T1 - Divalent metal phosphonates – new aspects for syntheses, in situ characterization and structure solution N2 - Divalent metal phosphonates are promising hybrid materials with a broad field of application. The rich coordination chemistry of the phosphonate linkers enables the formation of structures with different dimensionalities ranging from isolated complexes and layered structures to porous frameworks incorporating various functionalities through the choice of the building blocks. In brief, metal phosphonates offer an interesting opportunity for the design of multifunctional materials. Here, we provide a short review on the class of divalent metal phosphonates discussing their syntheses, structures, and applications. We present the advantages of the recently introduced mechanochemical pathway for the Synthesis of divalent phosphonates as a possibility to generate new, in certain cases metastable compounds. The benefits of in situ investigation of synthesis mechanisms as well as the implementation of sophisticated methods for the structure analysis of the resulting compounds are discussed. KW - Metal phosphonate KW - Mechanochemistry PY - 2017 DO - https://doi.org/10.1515/zkri-2016-1971 SN - 2194-4946 SN - 2196-7105 VL - 232 IS - 1-3 SP - 209 EP - 222 PB - De Gruyter AN - OPUS4-40003 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mitova, M. A1 - Iliev, M. A1 - Nováková, A. A1 - Gorbushina, Anna A1 - Groudeva, V.I. A1 - Martin-Sanchez, Pedro Maria T1 - Diversity and biocide susceptibility of fungal assemblages dwelling in the Art Gallery of Magura Cave, Bulgaria N2 - Magura Cave, north-western Bulgaria, possesses valuable rock-art paintings made with bat guano and dated from the period between the Eneolithic and Bronze Ages. Since 2008, the Art Gallery is closed to the general public in order to protect the paintings from vandalism, microclimatic changes caused by visitors and artificial illumination, and the consequent growth of fungi and phototrophs. Nevertheless, some tourist visits are allowed under the supervision of cave managers. This study provides the first scientific report on cultivable fungal assemblages dwelling different substrata in the Art Gallery. A total of 78 strains, belonging to 37 OTUs (Ascomycota 81%, Zygomycota 13%, Basidiomycota 5%), were isolated in the study. This fungal diversity was clearly dominated by Penicillium (50% of strains) and Aspergillus (13%). The most relevant visible fungal colonies were detected in sediments rich in bat guano, where, besides Penicillium, other guanophilic fungi such as Mucor, Mortierella, Trichosporon and Trichoderma were dominant. Conversely, scarce fungi were detected on rock surface of painted walls. Based on the biocide susceptibility assay, octylisothiazolinone (OIT) and benzalkonium chloride (BAC) were effective inhibiting the in vitro growth of dominant fungal species in Magura Cave, when applied at concentrations ranged from 100 to 1,000 mg/L. These data provide a valuable knowledge about Magura fungi, and exemplify a type of preliminary test that may be conducted before planning any biocide treatment. However, considering the irreversible effects of biocides on the ecological balance in caves, and the low fungal contamination in painted walls of Magura Cave, there is no reason to use conventional biocides in this cave. Further studies, monitoring microbial communities and microclimatic parameters, should be conducted to improve the knowledge on microbial ecology in Magura Cave and possible human impacts, as well as to allow the early detection of potential microbial outbreaks. KW - Fungi KW - Rock-art caves KW - Biocides PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-397436 DO - https://doi.org/10.5038/1827-806X.46.1.2061 SN - 0392-6672 VL - 46 IS - 1 SP - 67 EP - 80 PB - Scholar Commons CY - Tampa, FL, USA AN - OPUS4-39743 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lichtenstein, D. A1 - Meyer, T. A1 - Böhmert, L. A1 - Juling, S. A1 - Fahrenson, C. A1 - Selve, S. A1 - Thünemann, Andreas A1 - Meijer, J. A1 - Estrela-Lopis, I. A1 - Braeuning, A. A1 - Lampen, A. T1 - Dosimetric quantification of coating-related uptake of silver nanoparticles N2 - The elucidation of mechanisms underlying the cellular uptake of nanoparticles (NPs) is an important topic in nanotoxicological research. Most studies dealing with silver NP uptake provide only qualitative data about internalization efficiency and do not consider NP-specific dosimetry. Therefore, we performed a comprehensive comparison of the cellular uptake of differently coated silver NPs of comparable size in different human intestinal Caco-2 cell-derived models to cover also the influence of the intestinal mucus barrier and uptake-specialized M-cells. We used a combination of the Transwell system, transmission electron microscopy, atomic absorption spectroscopy, and ion beam microscopy techniques. The computational in vitro sedimentation, diffusion, and dosimetry (ISDD) model was used to determine the effective dose of the particles in vitro based on their individual physicochemical characteristics. Data indicate that silver NPs with a similar size and shape show coating-dependent differences in their uptake into Caco-2 cells. The internalization of silver NPs was enhanced in uptake-specialized M-cells while the mucus did not provide a substantial barrier for NP internalization. ISDD modeling revealed a fivefold underestimation of dose–response relationships of NPs in in vitro assays. In summary, the present study provides dosimetry-adjusted quantitative data about the influence of NP coating materials in cellular uptake into human intestinal cells. Underestimation of particle effects in vitro might be prevented by using dosimetry models and by considering cell models with greater proximity to the in vivo situation, such as the M-cell model. KW - Silver nanoparticles KW - Small-angle X-ray scattering KW - Saxs PY - 2017 DO - https://doi.org/10.1021/acs.langmuir.7b01851 SN - 0743-7463 VL - 33 IS - 45 SP - 13087 EP - 13097 PB - Americal Chemical Society AN - OPUS4-42875 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Falkenreck, Thora A1 - Klein, M. A1 - Böllinghaus, Thomas T1 - Dynamic compressive behaviour of weld joints N2 - Materials used in military applications have to withstand multiple threats like ballistics and explosions. Thus, high-strength low alloyed (HSLA) steels are used. The main joining technique for metals is welding. Therefore, analysing the dynamic impact behaviour of high-strength welds is very important to fulfil these demands. Investigation of welds at high strain rates has rarely been conducted in the past. To determine the dynamic impact behaviour of hybrid laser-arc welds, the Split Hopkinson Pressure Bar (SHPB) technique was used. The base material was a quenched and tempered fine-grained armour steel with yield strength of 1100 MPa. First, a full hybrid laser-arc weld was investigated by extracting specimens consisting of weld metal and heat affected base material. The influence of two variables, the cooling time between 800 °C and 500 °C (t8/5) and strength of filler material, on the impact behaviour was studied. The cooling time t8/5 was varied by preheating to influence the microstructure in the HAZ and to analyse the effect on the hardness and dynamic compressive strength. Subsequent analysis to detail the original Investigation was carried out by dilatometer heat treatment of specimens to create homogenous subzones of the weld. These specimens have a homogenous microstructure of HAZ and were tested by SHPB to determine the stress-strain characteristics for the different microstructures of HAZ. The results of the weld specimen showed the effect of preheating and filler material strength on the dynamic compressive behaviour. The analysis of the different microstructures of the HAZ indicated that especially the tempered microstructure caused a reduction in dynamic compressive strength. KW - SHPB KW - Hybrid laser-arc weld KW - Dilatometry PY - 2017 DO - https://doi.org/10.1016/j.msea.2017.07.032 SN - 0921-5093 SN - 1873-4936 VL - 702 SP - 322 EP - 330 AN - OPUS4-41904 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Babutzka, Martin A1 - Heyn, A. T1 - Dynamic tafel factor adaption for the evaluation of instantaneous corrosion rates on zinc by using gel-type electrolytes N2 - The paper presents a new method for the determination and evaluation of tafel factors using gel-type electrolytes and electrochemical frequency modulation technique (EFM). This relatively new electrochemical method offers the possibility to determine both polarization resistances and tafel factors within one measurement and in short measuring intervals. Starting from a comprehensive parameter study it is shown that a direct relationship between the two values exists that can be described mathematically. This contribution presents the determined tafel factors for the system gel-type electrolyte/zinc and discusses their applicability and their limits. T2 - 19th Chemnitz Seminar on Materials Engineering – 19. Werkstofftechnisches Kolloquium CY - Chemnitz, Germany DA - 16.03.2017 KW - Gel-type electrolytes KW - Gelartige Elektrolyte KW - Zinc KW - Zink KW - Stern Geary constant KW - Stern-Geary-Konstante PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-394324 UR - http://iopscience.iop.org/article/10.1088/1757-899X/181/1/012021/pdf DO - https://doi.org/10.1088/1757-899X/181/1/012021 SN - 1757-899X SN - 1757-8981 VL - 181 IS - Conference 1 SP - Article UNSP 012021, 1 EP - 11 PB - IOP Publishing CY - Bristol, UK AN - OPUS4-39432 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Meyer, Susann A1 - Schröter, Maria-Astrid A1 - Hahn, Marc Benjamin A1 - Solumon, Tihomir A1 - Strum, Heinz A1 - Kunte, Hans-Jörg T1 - Ectoine can enhance structural changes in DNA in vitro N2 - Strand breaks and conformational changes of DNA have consequences for the physiological role of DNA. The natural protecting molecule ectoine is beneficial to entire bacterial cells and biomolecules such as proteins by mitigating detrimental effects of environmental stresses. It was postulated that ectoine-like molecules bind to negatively charged spheres that mimic DNA surfaces. We investigated the effect of ectoine on DNA and whether ectoine is able to protect DNA from damages caused by ultraviolet radiation (UV-A). In order to determine different isoforms of DNA, agarose gel electrophoresis and atomic force microscopy experiments were carried out with plasmid pUC19 DNA. Our quantitative results revealed that a prolonged incubation of DNA with ectoine leads to an increase in transitions from supercoiled (undamaged) to open circular (single-strand break) conformation at pH 6.6. The effect is pH dependent and no significant changes were observed at physiological pH of 7.5. After UV-A irradiation in ectoine solution, changes in DNA conformation were even more pronounced and this effect was pH dependent. We hypothesize that ectoine is attracted to the negatively charge surface of DNA at lower pH and therefore fails to act as a stabilizing agent for DNA in our in vitro experiments. KW - Ectoine KW - DNA KW - UV radiation PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-413139 DO - https://doi.org/10.1038/s41598-017-07441-z VL - 7 IS - 1 SP - Article 7170, 1 EP - 10 AN - OPUS4-41313 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schröter, Maria-Astrid A1 - Meyer, Susann A1 - Hahn, Marc Benjamin A1 - Solomun, Tihomir A1 - Sturm, Heinz A1 - Kunte, Hans-Jörg T1 - Ectoine protects DNA from damage by ionizing radiation N2 - Ectoine plays an important role in protecting biomolecules and entire cells against environmental stressors such as salinity, freezing, drying and high temperatures. Recent studies revealed that ectoine also provides effective protection for human skin cells from damage caused by UV-A radiation. These protective properties make ectoine a valuable compound and it is applied as an active ingredient in numerous pharmaceutical devices and cosmetics. Interestingly, the underlying mechanism resulting in protecting cells from radiation is not yet fully understood. Here we present a study on ectoine and its protective influence on DNA during electron irradiation. Applying gel electrophoresis and atomic force microscopy, we demonstrate for the first time that ectoine prevents DNA strand breaks caused by ionizing electron radiation. The results presented here point to future applications of ectoine for instance in cancer radiation therapy. KW - Plasmid DNA pUC19 KW - Electron irradiation 30 [kV] KW - Effective irradiation dose 0.2-16 [Gy] KW - Gel electrophoresis KW - AFM intermittent contact KW - Radioprotector ectoine KW - Compatible solute PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-428287 DO - https://doi.org/10.1038/s41598-017-15512-4 SN - 2045-2322 VL - 7 IS - 1 SP - 15272, 1 EP - 15272, 7 PB - Nature AN - OPUS4-42828 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kingelhöffer, Hellmuth A1 - Affeldt, E. E. A1 - Bache, M. A1 - Bartsch, M. A1 - Beck, T. A1 - Christ, H. J. A1 - Fedelich, Bernard A1 - Hähner, P. A1 - Holdsworth, S. R. A1 - Lang, K.-H. A1 - McGaw, M. A1 - Olbricht, Jürgen A1 - Remy, L. A1 - Skrotzki, Birgit A1 - Stekovich, S. T1 - Editorial - Special issue: Recent developments in thermo-mechanical fatigue N2 - Components in the Aerospace, Power and Automotive engineering sectors are frequently subjected to cyclic stresses induced by thermal fluctuations and mechanical loads. For the design of such components, reliable material property data are required which need to be acquired using well accepted and reproducible test procedures for thermo-mechanical fatigue (TMF) loading. There is limited availability of proven TMF data indicating there is need for further research and testing. The TMF behaviour of materials is often desired to be simulated in models which describe the cyclic stress-strain behaviour, the fatigue life and the cyclic crack growth behaviour. There is a continuous need for the development and amendment of such models. Models can be validated by using materials in industrial applications which are subjected to TMF loading. The 3rd Workshop on Thermo-Mechanical Fatigue was held on 27–29 April 2016 at BAM, Berlin, Germany. The workshop was attended by 90 attendees coming from 17 countries in the world. 38 presentations including five poster presentations were held. The following topics were covered by the workshop: – TMF of materials coated with Thermal Barrier Coatings. – Thermal Gradient Mechanical Fatigue. – TMF crack growth. – TMF + High Cycle Fatigue. – TMF Modelling and Lifetime Prediction. – TMF Properties of steels, cast iron, Al-, Mg- and Ni-alloys – Advanced TMF Testing Techniques. – Industrial Applications. A panel discussion was held regarding the present state of TMF testing standards (ISO and ASTM) and their potential for improvement. The discussion and contributions were summarized and forwarded to the standard committees. The 3rd TMF-Workshop ensured the continuation of international exchange of knowledge providing a forum to present and discuss all recent developments in the field of thermo-mechanical fatigue. The current special issue publishes eleven selected papers of the 3rd TMF-Workshop 2016. The papers were peer reviewed by a number of experts in the Thermo-Mechanical Fatigue sector. I hope you will enjoy reading papers of this special issue. T2 - 3rd International Workshop on Thermo-Mechanical Fatigue (TMF-Workshop 2016) CY - Berlin, Germany DA - 27.04.2016 KW - Fatigue damage KW - Thermo-mechanical fatigue KW - Fatigue life time KW - Life time prediction KW - TMF PY - 2017 DO - https://doi.org/10.1016/j.ijfatigue.2017.02.002 SN - 0142-1123 VL - 99 IS - 2 SP - 215 PB - Elsevier CY - Oxford AN - OPUS4-40895 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hertwig, Andreas A1 - Hinrichs, K. A1 - Beck, Uwe A1 - Esser, N. T1 - Editorial to the proceedings of the 7th conference on spectroscopic N2 - The 7th International Conference on Spectroscopic Ellipsometry (ICSE-7) was held in Berlin in June 2016, jointly organised by ICSE and BAM. The publication of the proceedings special issue in Applied Surface Science follows this event. In the special issue, about 100 articles on current topics of optics and surface science related to ellipsometry, polarimetry, and similar techniques are presented, underpinning the high significance of these techniques for many fields of materials science. T2 - 7th International Conference on Spectroscopic Ellipsometry, ICSE-7 CY - Berlin, Germany DA - 06.06.2016 KW - Spectroscopic ellipsomety PY - 2017 DO - https://doi.org/10.1016/j.apsusc.2017.04.081 SN - 0169-4332 VL - 2017 IS - 421 SP - 269 EP - 270 PB - Elsevier B.V. AN - OPUS4-42554 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jaunich, Matthias T1 - Editorial: Shape memory polymers N2 - In this editorial the focus lies on the testing of shape memory materials. KW - Shape memory polymer KW - Testing PY - 2017 DO - https://doi.org/10.1016/j.polymertesting.2017.08.019 SN - 0142-9418 VL - 62 SP - A1 PB - Elsevier CY - Oxford AN - OPUS4-41714 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Linhares, F.N. A1 - Kersch, M. A1 - Niebergall, Ute A1 - Leite, M.Ch.A.M. A1 - Altstädt, V. A1 - Furtado, C.R.G. T1 - Effect of different sulphur-based crosslink networks on the nitrile rubber resistance to biodiesel N2 - Biodiesel possesses some comparable physical properties to petroleum diesel in addition to its improved environmental benefits. Nonetheless, both fuels differ greatly with respect to their chemical compositions. Therefore, the compatibility of the materials, which are commonly employed in contact with diesel, must also be assured for biodiesel. This paper assessed the influence of sulphur-based curing systems on the resistance of nitrile rubber to soybean biodiesel. Formulations were prepared using highacrylonitrile-content nitrile rubber by employing a two-level experimental design. The amounts of two different accelerators and sulphur were varied to achieve different types of vulcanisation systems. Thermal analyses, mechanical tests and microscopy analyses were conducted to evaluate the behaviour of the material after contact with biodiesel. The results showed that the choice of the accelerator played an important role on the resistance of the rubber to the biofuel, and crosslink density was not a key factor with respect to the resistance. KW - Soyean oil KW - Nitrile rubber KW - Compatibility KW - Vulcanisation system KW - Biodiesel KW - Resistance PY - 2017 DO - https://doi.org/10.1016/j.fuel.2016.11.060 SN - 0016-2361 SN - 1873-7153 VL - 191 SP - 130 EP - 139 AN - OPUS4-39006 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Cabeza, Sandra A1 - Garces, G. A1 - Adeva, Paloma A1 - Kabra, S. A1 - Gan, W. T1 - Effect of Extrusion Temperature on the Plastic Deformation of an Mg-Y-Zn Alloy Containing LPSO Phase Using In Situ Neutron Diffraction N2 - The evolution of the internal strains during in situ tension and compression tests has been measured in an MgY2Zn1 alloy containing long-period stacking ordered (LPSO) phase using neutron diffraction. The alloy was extruded at two different temperatures to study the influence of the microstructure and texture of the magnesium and the LPSO phases on the deformation mechanisms. The alloy extruded at 623 K (350 °C) exhibits a strong fiber texture with the basal plane parallel to the extrusion direction due to the presence of areas of coarse non-recrystallised grains. However, at 723 K (450 °C), the magnesium phase is fully recrystallised with grains randomly oriented. On the other hand, at the two extrusion temperatures, the LPSO phase orients their basal plane parallel to the extrusion direction. Yield stress is always slightly higher in compression than in tension. Independently on the stress sign and the extrusion temperature, the beginning of plasticity is controlled by the activation of the basal slip system in the dynamic recrystallized grains. Therefore, the elongated fiber-shaped LPSO phase which behaves as the reinforcement in a metal matrix composite is responsible for this tension–compression asymmetry. KW - Mg-Y-Zn Alloy KW - LPSO Phase KW - Neutron Diffraction PY - 2017 DO - https://doi.org/10.1007/s11661-017-4284-6 VL - 48A IS - 11 SP - 5332 EP - 5343 PB - Spinger AN - OPUS4-42935 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nadammal, Naresh A1 - Cabeza, Sandra A1 - Mishurova, Tatiana A1 - Thiede, Tobias A1 - Kromm, Arne A1 - Seyfert, Christoph A1 - Farahbod, Lena A1 - Haberland, Christoph A1 - Schneider, Judith Ann A1 - Portella, Pedro Dolabella A1 - Bruno, Giovanni T1 - Effect of hatch length on the development of microstructure, texture and residual stresses in selective laser melted superalloy Inconel 718 N2 - In the present study, samples fabricated by varying the deposition hatch length during selective laser melting of nickel based superalloy Inconel 718 were investigated. Microstructure and texture of these samples was characterized using scanning electron microscopy, combined with electron back-scattered diffraction, and residual stress assessment, using neutron diffraction method. Textured columnar grains oriented along the sample building direction were observed in the shorter hatch length processed sample. A ten-fold increase in the hatch length reduced the texture intensity by a factor of two attributed to the formation of finer grains in the longer hatch length sample. Larger gradients of transverse residual stress in the longer hatch length sample were also observed. Along the build direction, compressive stresses in the shorter hatch length and negligible stresses for the longer hatch length specimen were observed. Changes to the temperature gradient (G) in response to the hatch length variation, influenced the G to growth rate (R) ratio and the product G × R, in agreement with the microstructures and textures formed. For the residual stress development, geometry of the part also played an important role. In summary, tailored isotropy could be induced in Inconel 718 by a careful selection of parameters during selective laser melting. KW - Additive manufacturing KW - Nickel-based superalloy KW - Microstructure and texture KW - Residual stress KW - Electron back-scattered diffraction KW - Neutron diffraction PY - 2017 UR - http://www.sciencedirect.com/science/article/pii/S0264127517308018 DO - https://doi.org/10.1016/j.matdes.2017.08.049 SN - 0264-1275 VL - 134 SP - 139 EP - 150 PB - Elsevier CY - Oxford, UK AN - OPUS4-41606 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Cooper, R. A1 - Bruno, Giovanni A1 - Shyam, A. A1 - Watkins, T. A1 - Pandey, A. A1 - Wheeler, M. T1 - Effect of microcracking on the uniaxial tensile response of beta-eucryptite ceramics: Experiments and constitutive model N2 - A constitutive model for the nonlinear or “pseudoplastic” mechanical behavior in a linear-elastic solid with thermally induced microcracks is developed and applied to experimental results. The model is termed strain dependent microcrack density approximation (SDMDA) and is an extension of the modified differential scheme that describes the slope of the stress-strain curves of microcracked solids. SDMDA allows a continuous variation in the microcrack density with tensile loading. Experimental uniaxial tensile response of β-eucryptite glass and ceramics with controlled levels of microcracking is reported. It is demonstrated that SDMDA can well describe the extent of non-linearity in the experimental uniaxial tensile response of β-eucryptite with varying levels of microcracking. The advantages of the SDMDA are discussed in regard to tensile loading. KW - Microcracking KW - β-eucryptite KW - Young's modulus KW - Modeling KW - Tensile behavior PY - 2017 DO - https://doi.org/10.1016/j.actamat.2017.06.033 SN - 1359-6454 SN - 1873-2453 VL - 135 SP - 361 EP - 371 PB - Elsevier Ltd. AN - OPUS4-40859 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wiedmann, A. A1 - Weise, Frank A1 - Kotan, E. A1 - Müller, H. S. A1 - Meng, Birgit T1 - Effects of fatigue loading and alkali-silica reaction on the mechanical behaviour of pavement concrete N2 - The primary aim of this paper is to analyze the impact of mechanical pre-damage and alkali–silica reaction (ASR) on the fracture mechanical properties of pavement concrete. For this purpose, a four point bending test was applied to large format beams to produce a defined level of cyclic pre-damage. The fatigue-induced concrete degradation process was simultaneously recorded using a testing procedure specifically developed for the purpose. In addition, fatigue-induced cracks on extracted drilling cores were spatially visualized and quantified using micro X-ray 3D-computed tomography (3D-CT). The storage of the small-format test specimens, with and without cyclic pre-damage, in an ASR-conducive environment showed that pre-damage leads to an increase in ASR damage processes. Subsequent structural mechanical investigations on small format specimens with and without pre-damage show that fatigue loading and ASR significantly influence fracture mechanical parameters of the concrete. KW - Acoustic emissions analysis KW - Alkali-silica reaction KW - Concrete pavement KW - Fatigue loading KW - Fracture energy KW - Monitoring of damage KW - Tensile strength KW - Ultrasonic velocity PY - 2017 DO - https://doi.org/10.1002/suco.201600179 SN - 1751-7648 SN - 1464-4177 VL - 18 IS - 4 SP - 539 EP - 549 PB - Ernst & Sohn AN - OPUS4-41007 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rosemann, Paul A1 - Müller, C. A1 - Kauss, N. A1 - Halle, T. T1 - Einfluss der Wärmebehandlung auf die Korrosionsbeständigkeit von Schneidwaren N2 - Härte und Korrosionsbeständigkeit sind die wichtigsten Qualitätsmerkmale von Schneidwaren. Diese werden nur durch eine optimal durchgeführte Wärmebehandlung des martensitischen nichtrostenden Stahls 1.4116 (X50CrMoV15) erreicht. In der industriellen Fertigung wird die Korrosionsbeständigkeit von Schneidwaren durch Wechseltauchversuche überprüft, die herstellerübergreifend eine große Schwankung der Korrosionsbeständigkeit belegen. In den letzten Jahren wurden neue elektrochemische Untersuchungsmethoden für die Werkstoffgruppe der martensitischen nichtrostenden Stähle entwickelt, welche die geringe Lochkorrosionsbeständigkeit von Schneidwaren auf das Phänomen der Chromverarmung zurückzuführen. Derzeit wird in der wissenschaftlichen und in der industriellen Gemeinschaft der Schritt des Anlassens als Hauptursache der Chromverarmung angesehen. Bei Schneidwaren sind die Anlasstemperaturen aber zu gering, um die auftretende Chromverarmung zu erklären. Aus diesem Grund wurden drei verschiedene Wärmebehandlungsparameter (Austenitisierungsdauer, Abkühlgeschwindigkeit und Anlasstemperatur) systematische untersucht, um deren Beitrag zur Chromverarmung darzustellen. Dazu wird die Untersuchungsmethode der elektrochemisch potentiodynamischen Reaktivierung (EPR) eingesetzt, die sehr sensibel auf Veränderungen im Gefüge reagiert und den Grad an Chromverarmung ermittelt. Außerdem wurde die KorroPad-Prüfung durchgeführt und kritische Lochkorrosionspotentiale ermittelt, um den Zusammenhang zwischen Chromverarmung und Lochkorrosionsbeständigkeit herzustellen. Die Ergebnisse aller Untersuchungen verdeutlichen wie eng das Prozessfenster ist, in dem Schneidwaren mit hoher Korrosionsbeständigkeit hergestellt werden können. T2 - 72. HärtereiKongress CY - Cologne, Germany DA - 26.10.2016 KW - Schneidwaren KW - Wärmebehandlung KW - nichtrostender Stahl KW - martensitisch KW - Lochkorrosion KW - EPR KW - KorroPad PY - 2017 DO - https://doi.org/10.3139/105.110317 SN - 1867-2493 VL - 72 IS - 2 SP - 87 EP - 98 PB - Carl Hanser CY - München AN - OPUS4-41241 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -