Pundt, Astrid

[["dc.bibliographiccitation.firstpage","S885"],["dc.bibliographiccitation.journal","Journal of Alloys and Compounds"],["dc.bibliographiccitation.lastpage","S890"],["dc.bibliographiccitation.volume","509"],["dc.contributor.author","Izawa, C."],["dc.contributor.author","Wagner, S."],["dc.contributor.author","Martin, M."],["dc.contributor.author","Weber, S."],["dc.contributor.author","Bourgeon, A."],["dc.contributor.author","Pargeter, R."],["dc.contributor.author","Michler, Thorsten"],["dc.contributor.author","Pundt, Astrid"],["dc.date.accessioned","2018-11-07T08:52:07Z"],["dc.date.available","2018-11-07T08:52:07Z"],["dc.date.issued","2011"],["dc.description.abstract","The local surface chemistry of a low-Ni austenitic stainless steel AISI type 304 used for tensile testing in hydrogen atmosphere is characterized by secondary ion mass spectrometry (SIMS). A chemical map on cylindrical austenitic stainless steel samples can be obtained even after a tensile test. In an effort to obtain the proper chemical element distribution on the samples, the influence of contamination and sample orientation is discussed. An iron oxide on top of a chromium oxide layer is present and Si segregation at grain boundaries is detected. Oxides are judged to reduce the initial hydrogen attack but to be of minor importance for crack propagation during the embrittlement process. (C) 2011 Elsevier B.V. All rights reserved."],["dc.identifier.doi","10.1016/j.jallcom.2010.12.143"],["dc.identifier.isi","000295695500084"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/22092"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Elsevier Science Sa"],["dc.publisher.place","Lausanne"],["dc.relation.conference","12th International Symposium on Metal-Hydrogen Systems, Fundamentals and Applications (MH2010)"],["dc.relation.eventend","2010-07-23"],["dc.relation.eventlocation","Moscow, Russia"],["dc.relation.eventstart","2010-07-19"],["dc.relation.issn","0925-8388"],["dc.relation.orgunit","Institut für Materialphysik"],["dc.title","SIMS study on the surface chemistry of stainless steel AISI 304 cylindrical tensile test samples showing hydrogen embrittlement"],["dc.type","conference_paper"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","709"],["dc.bibliographiccitation.issue","9"],["dc.bibliographiccitation.journal","Scripta Materialia"],["dc.bibliographiccitation.lastpage","712"],["dc.bibliographiccitation.volume","62"],["dc.contributor.author","Tal-Gutelmacher, E."],["dc.contributor.author","Pundt, Astrid"],["dc.contributor.author","Kirchheim, Reiner"],["dc.date.accessioned","2018-11-07T08:43:53Z"],["dc.date.available","2018-11-07T08:43:53Z"],["dc.date.issued","2010"],["dc.description.abstract","The effect of residual hydrogen, sorbed during the deposition process, on the hydrogenation behavior of ion-beam sputtered titanium thin films was investigated. Electromotive force and in situ stress measurements were conducted to study hydrogen absorption, phase boundaries and hydrogen-induced stress development in the Ti-H thin film system. Tests were conducted on both as-sputtered and previously discharged films; the effect of residual hydrogen is significantly manifested in the thermodynamic isotherms and stress-concentration curves. (C) 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved."],["dc.description.sponsorship","Alexander von Humboldt foundation"],["dc.identifier.doi","10.1016/j.scriptamat.2010.01.037"],["dc.identifier.isi","000275933700020"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/20077"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Pergamon-elsevier Science Ltd"],["dc.relation.issn","1359-6462"],["dc.title","The effect of residual hydrogen on hydrogenation behavior of titanium thin films"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","479"],["dc.bibliographiccitation.journal","Journal of Alloys and Compounds"],["dc.bibliographiccitation.lastpage","483"],["dc.bibliographiccitation.volume","446"],["dc.contributor.author","Cizek, Jakub"],["dc.contributor.author","Proeger, Till E."],["dc.contributor.author","Danis, Stanislav"],["dc.contributor.author","Cieslar, M."],["dc.contributor.author","Brauer, Gerhard"],["dc.contributor.author","Anwand, W."],["dc.contributor.author","Kirchheim, Reiner"],["dc.contributor.author","Pundt, Astrid"],["dc.date.accessioned","2018-11-07T10:57:35Z"],["dc.date.available","2018-11-07T10:57:35Z"],["dc.date.issued","2007"],["dc.description.abstract","The introduction of new defects due to H-loading of Nb, their population as a function of the H concentration, and the mechanism of their formation are investigated by positron annihilation spectroscopy (PAS). In addition, X-ray diffraction (XRD), and transmission electron microscopy (TEM) are applied. Furthermore, the results obtained by the experimental techniques are compared with theoretical calculations of energetic stability and positron characteristics of various defect-H configurations. It is found that vacancies surrounded by H atoms are introduced into the specimens by H-loading. The density of these vacancy-H complexes increases with increasing concentration of H in the specimens. The H-induced vacancies are formed even in the alpha-phase field, when the metal-H system is a single phase solid solution. The stability of the H-induced defects and the mechanism of their formation are discussed. (C) 2006 Elsevier B.V. All rights reserved."],["dc.identifier.doi","10.1016/j.jallcom.2006.11.105"],["dc.identifier.isi","000250822900102"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/50289"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Elsevier Science Sa"],["dc.publisher.place","Lausanne"],["dc.relation.conference","10th International Symposium on Metal-Hydrogen Systems, Fundamentals and Applications"],["dc.relation.eventlocation","Lahaina, HI"],["dc.relation.issn","0925-8388"],["dc.title","Hydrogen-induced defects in niobium"],["dc.type","conference_paper"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","224106"],["dc.bibliographiccitation.issue","22"],["dc.bibliographiccitation.journal","PHYSICAL REVIEW B"],["dc.bibliographiccitation.volume","69"],["dc.contributor.author","Cizek, Jakub"],["dc.contributor.author","Prochazka, Ivan"],["dc.contributor.author","Becvar, F."],["dc.contributor.author","Kuzel, R."],["dc.contributor.author","Cieslar, M."],["dc.contributor.author","Brauer, Gerhard"],["dc.contributor.author","Anwand, W."],["dc.contributor.author","Kirchheim, Reiner"],["dc.contributor.author","Pundt, Astrid"],["dc.date.accessioned","2018-11-07T10:48:43Z"],["dc.date.available","2018-11-07T10:48:43Z"],["dc.date.issued","2004"],["dc.description.abstract","Our aim in the present work was to investigate changes of the defect structure of bulk niobium induced by hydrogen loading. The evolution of the microstructure with increasing hydrogen concentration was studied by x-ray diffraction and two complementary techniques of positron annihilation spectroscopy (PAS), namely positron lifetime spectroscopy and slow positron implantation spectroscopy with the measurement of Doppler broadening, in defect-free Nb (99.9%) and Nb containing a remarkable number of dislocations. These samples were electrochemically loaded with hydrogen up to x(H)=0.06 [H/Nb], i.e., in the alpha-phase region, and it was found that the defect density increases with hydrogen concentration in both Nb samples. This means that hydrogen-induced defects are created in the Nb samples. A comparison of PAS results with theoretical calculations revealed that vacancy-hydrogen complexes are introduced into the samples due to hydrogen loading. Most probably these are vacancies surrounded by 4 hydrogen atoms."],["dc.identifier.doi","10.1103/PhysRevB.69.224106"],["dc.identifier.isi","000222530900027"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/48260"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Physical Soc"],["dc.relation.issn","2469-9969"],["dc.relation.issn","2469-9950"],["dc.title","Hydrogen-induced defects in bulk niobium"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","123"],["dc.bibliographiccitation.journal","JOURNAL OF NANO RESEARCH"],["dc.bibliographiccitation.lastpage","133"],["dc.bibliographiccitation.volume","26"],["dc.contributor.author","Cizek, Jakub"],["dc.contributor.author","Melikhova, Oksana"],["dc.contributor.author","Vlcek, Marian"],["dc.contributor.author","Lukac, Frantisek"],["dc.contributor.author","Vlach, Martin"],["dc.contributor.author","Dobron, Patrik"],["dc.contributor.author","Prochazka, Ivan"],["dc.contributor.author","Anwand, Wolfgang"],["dc.contributor.author","Brauer, Gerhard"],["dc.contributor.author","Wagner, Stefan"],["dc.contributor.author","Uchida, Helmut"],["dc.contributor.author","Gemma, Ryota"],["dc.contributor.author","Pundt, Astrid"],["dc.date.accessioned","2018-11-07T09:46:42Z"],["dc.date.available","2018-11-07T09:46:42Z"],["dc.date.issued","2014"],["dc.description.abstract","Hydrogen interaction with defects and structural development of Pd films with various microstructures were investigated. Nanocrystalline, polycrystalline and epitaxial Pd films were prepared and electrochemically loaded with hydrogen. Structural changes of Pd films caused by absorbed hydrogen were studied by in-situ X-ray diffraction combined with acoustic emission and measurement of electromotorical force. Development of defects during hydrogen loading was investigated by positron annihilation spectroscopy. It was found that hydrogen firstly fills open volume defects existing already in the films and subsequently it occupies also interstitial sites in Pd lattice. Absorbed hydrogen causes volume expansion, which is strongly anisotropic in thin films. This introduces high stress into the films loaded with hydrogen. Acoustic emission measurements revealed that when hydrogen-induced stress achieves a certain critical level rearrangement of misfit dislocations takes place. The stress which grows with increasing hydrogen concentration can be further released by plastic deformation and also by detachment of the film from the substrate."],["dc.identifier.doi","10.4028/www.scientific.net/JNanoR.26.123"],["dc.identifier.isi","000330816600018"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/34943"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Trans Tech Publications Ltd"],["dc.relation.issn","1661-9897"],["dc.relation.issn","1662-5250"],["dc.title","Hydrogen Interaction with Defects in Nanocrystalline, Polycrystalline and Epitaxial Pd Films"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","12115"],["dc.bibliographiccitation.issue","27"],["dc.bibliographiccitation.journal","International Journal of Hydrogen Energy"],["dc.bibliographiccitation.lastpage","12125"],["dc.bibliographiccitation.volume","38"],["dc.contributor.author","Cizek, Jakub"],["dc.contributor.author","Melikhova, Oksana"],["dc.contributor.author","Vlcek, Marian"],["dc.contributor.author","Lukac, Frantisek"],["dc.contributor.author","Vlach, Martin"],["dc.contributor.author","Prochazka, Ivan"],["dc.contributor.author","Anwand, W."],["dc.contributor.author","Brauer, Gerhard"],["dc.contributor.author","Muecklich, Arndt"],["dc.contributor.author","Wagner, S."],["dc.contributor.author","Uchida, Helmut Takahiro"],["dc.contributor.author","Pundt, Astrid"],["dc.date.accessioned","2018-11-07T09:19:57Z"],["dc.date.available","2018-11-07T09:19:57Z"],["dc.date.issued","2013"],["dc.description.abstract","The development of the microstructure in nanocrystalline, polycrystalline and epitaxial Pd films loaded with hydrogen is investigated. Structural changes in Pd films loaded with hydrogen were characterized by positron annihilation spectroscopy combined with electron microscopy and X-ray diffraction. It was found that hydrogen charging causes plastic deformation which leads to an increase of the defect density in all Pd films studied. Moreover, the formation of buckles was observed in nanocrystalline and polycrystalline Pd films loaded above a certain critical hydrogen concentration. Buckling leads to detachment of the film from the substrate and this is accompanied with in-plane stress relaxation and plastic deformation of the film. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved."],["dc.identifier.doi","10.1016/j.ijhydene.2013.03.096"],["dc.identifier.isi","000324563200051"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/28761"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Pergamon-elsevier Science Ltd"],["dc.relation.issn","0360-3199"],["dc.title","Hydrogen-induced microstructural changes of Pd films"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","262"],["dc.bibliographiccitation.journal","Acta Materialia"],["dc.bibliographiccitation.lastpage","267"],["dc.bibliographiccitation.volume","155"],["dc.contributor.author","Martin, May L."],["dc.contributor.author","Pundt, Astrid"],["dc.contributor.author","Kirchheim, Reiner"],["dc.date.accessioned","2020-12-10T14:14:52Z"],["dc.date.available","2020-12-10T14:14:52Z"],["dc.date.issued","2018"],["dc.identifier.doi","10.1016/j.actamat.2018.06.011"],["dc.identifier.issn","1359-6454"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/71529"],["dc.language.iso","en"],["dc.notes.intern","DOI Import GROB-354"],["dc.title","Hydrogen-induced accelerated grain growth in vanadium"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","243108"],["dc.bibliographiccitation.issue","24"],["dc.bibliographiccitation.journal","Applied Physics Letters"],["dc.bibliographiccitation.volume","106"],["dc.contributor.author","Hamm, Magnus"],["dc.contributor.author","Burlaka, Vladimir"],["dc.contributor.author","Wagner, S."],["dc.contributor.author","Pundt, Astrid"],["dc.date.accessioned","2018-11-07T09:55:51Z"],["dc.date.available","2018-11-07T09:55:51Z"],["dc.date.issued","2015"],["dc.description.abstract","Nano-materials are commonly stabilized by supports to maintain their desired shape and size. When these nano-materials take up interstitial atoms, this attachment to the support induces mechanical stresses. These stresses can be high when the support is rigid. High stress in the nano-material is typically released by delamination from the support or by the generation of defects, e.g., dislocations. As high mechanical stress can be beneficial for tuning the nano-materials properties, it is of general interest to deduce how real high mechanical stress can be gained. Here, we show that below a threshold nano-material size, dislocation formation can be completely suppressed and, when delamination is inhibited, even the ultrahigh stress values of the linear elastic limit can be reached. Specifically, for hydrogen solved in epitaxial niobium films on sapphire substrate supports a threshold film thickness of 6 nm was found and mechanical stress of up to (-10 +/- 1) GPa was reached. This finding is of basic interest for hydrogen energy applications, as the hydride stability in metals itself is affected by mechanical stress. Thus, tuning of the mechanical stress-state in nano-materials may lead to improved storage properties of nano-sized materials. (C) 2015 AIP Publishing LLC."],["dc.description.sponsorship","Deutsche Forschungsgemeinschaft DFG [PU131/9-1, PU131/12-1]"],["dc.identifier.doi","10.1063/1.4922285"],["dc.identifier.isi","000356618700036"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/36841"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.relation.issn","1077-3118"],["dc.relation.issn","0003-6951"],["dc.relation.orgunit","Institut für Materialphysik"],["dc.title","Achieving reversibility of ultra-high mechanical stress by hydrogen loading of thin films"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","308"],["dc.bibliographiccitation.journal","Acta Materialia"],["dc.bibliographiccitation.lastpage","323"],["dc.bibliographiccitation.volume","67"],["dc.contributor.author","Gemma, Ryota"],["dc.contributor.author","Dobron, Patrik"],["dc.contributor.author","Cizek, Jakub"],["dc.contributor.author","Pundt, Astrid"],["dc.date.accessioned","2018-11-07T09:41:59Z"],["dc.date.available","2018-11-07T09:41:59Z"],["dc.date.issued","2014"],["dc.description.abstract","Hydrogen-induced elastic/plastic deformation was studied in V1-xFex (x = 0.02-0.08) films with thicknesses between 10 and 400 nm and prepared at different temperatures. The combination of several in situ techniques such as X-ray diffraction, acoustic emission, electromotive force and substrate curvature techniques allows sensitive studies of defects generated in these thin films As well as conventional out-of-plane linear elastic film expansion and in-plane compressive stress increase during hydrogen absorption, the investigations uncovered new details: as soon as hydrogen predominately solved in interstitial lattice sites, discrete stress relaxation (DSR) events were detected, after which the film continued to behave in a linear elastic manner. DSRs were interpreted by uncorrelated movement of pre-existing dislocations. Particularly in the case of films deposited at higher temperatures, in-plane tensile stress was found at very small H concentrations of less than 0.005 H/V. Upon further H uptake, this turned into compressive stress. However, this stress increase differed from theoretical predictions. This behavior is explained by the generation of superabundant vacancies. Dislocation emission and plastic deformation are linked to the formation of the hydride phase in the V1-xFex films."],["dc.identifier.doi","10.1016/j.actamat.2013.12.034"],["dc.identifier.isi","000333495200026"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/33854"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Pergamon-elsevier Science Ltd"],["dc.relation.issn","1873-2453"],["dc.relation.issn","1359-6454"],["dc.title","Stress release and defect occurrence in V-1_Fe-x(x) films upon hydrogen loading: H-induced superabundant vacancies, movement and creation of dislocations"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","241"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Applied Surface Science"],["dc.bibliographiccitation.lastpage","244"],["dc.bibliographiccitation.volume","255"],["dc.contributor.author","Cizek, Jakub"],["dc.contributor.author","Prochazka, Ivan"],["dc.contributor.author","Vlach, Martin"],["dc.contributor.author","Zaludova, N."],["dc.contributor.author","Danis, Stanislav"],["dc.contributor.author","Dobron, Patrik"],["dc.contributor.author","Chmelik, F."],["dc.contributor.author","Brauer, Gerhard"],["dc.contributor.author","Anwand, W."],["dc.contributor.author","Muecklich, Arndt"],["dc.contributor.author","Nikitin, E."],["dc.contributor.author","Gemma, Ryota"],["dc.contributor.author","Kirchheim, Reiner"],["dc.contributor.author","Pundt, Astrid"],["dc.date.accessioned","2018-11-07T11:09:48Z"],["dc.date.available","2018-11-07T11:09:48Z"],["dc.date.issued","2008"],["dc.description.abstract","Hydrogen loading of thin films introduces very high compressive stresses which grow in magnitude with increasing hydrogen concentration. When the hydrogen-induced stresses exceed a certain critical in-plane stress value, the loaded film starts to detach from the substrate. This results in the formation of buckles of various morphologies in the film layer. Defect studies of a hydrogen loaded Pd film which undergoes a buckling process are presented, using slow positron implantation spectroscopy, in situ acoustic emission, and direct observations of the film structure by transmission electron and optical microscopies. It is found that buckling of the film occurs at hydrogen concentrations x(H) >= 0.1 and causes a significant increase of the dislocation density in the film. (c) 2008 Elsevier B.V. All rights reserved."],["dc.identifier.doi","10.1016/j.apsusc.2008.05.290"],["dc.identifier.isi","000259726900065"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/53087"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Elsevier Science Bv"],["dc.publisher.place","Amsterdam"],["dc.relation.conference","11th Workshop on Slow Position Beam Techniques for Solids and Surfaces"],["dc.relation.eventlocation","Musee Sci Naturelles, Orleans, FRANCE"],["dc.relation.issn","0169-4332"],["dc.title","Hydrogen-induced buckling of Pd films studied by positron annihilation"],["dc.type","conference_paper"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]