Papers by Keyword: Neutron Scattering

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Authors: Ralph Gilles, Debashis Mukherji, H. Eckerlebe, Pavel Strunz, Joachim Rösler
Abstract: Single crystal Ni-base superalloys based on the  /  system are widely used in gas turbine applications. To understand the formation of  precipitates, including size distribution and growth, we performed in situ small-angle neutron scattering (SANS) measurements at elevated temperatures and - together with TEM as well as , SEM imaging - studied changes in the precipitates in short and long time scale. In the early stages, a bimodal precipitate size distribution of precipitate is observed, which (depending on the annealing temperature) changes to a cuboidal or nearly spherical morphology with almostmore or less uniform ( unimodal?) size distribution. [Note: The term "more or less" is several times repeated in the text. I cannot imagine what it in fact means. Could you change it or explain in a more clear way?]
Authors: H.M. Mayer, Anke Pyzalla, Walter Reimers
Authors: V. L. Aksenov, A.M. Balagurov, V.P. Glazkov, D.P. Kozlenko, I.V. Naumov, B.N. Savenko, D.V. Sheptyakov, V.A. Somenkov, A.P. Bulkin, V.A. Kudryashev, V.A. Trounov
Authors: Eun Hye Na, Jae Young Choi, Baek-Seok Sung, Hu Chul Lee
Abstract: The effect of carbo-nitride precipitation on the recrystallization behavior of Ti-stabilized extra low carbon steels was investigated. The precipitation behavior of titanium carbo-nitride was analyzed using transmission electron microscopy (TEM), a chemical extraction method, and the small angle neutron scattering (SANS) method. The recrystallization temperature was varied from 590°C to 680°C depending on the alloy chemistry and hot rolling process. The total amount of precipitates in the hot bands did not significantly affect the recrystallization temperature of the alloys. Isothermal annealing treatment showed a plateau in the stress relaxation curves, i.e. a delay in the recovery, when precipitation occurred during the annealing treatment. A model developed to explain the dynamic interaction of the precipitation with the recovery in the microalloyed austenite was successfully adopted to simulate the delay of the recovery during the recrystallization treatment of the cold rolled Ti-stabilized extra low carbon steels.
Authors: M.C. Jermy, G.N. Greaves, M.E. Smith, G. Bushnell-Wye, A.C. Hannon, R.L. McGreevy, G. Derst, B. Tilley
Authors: Andrey M. Petrzhik, Yury N. Khaydukov, Luqman Mustafa, Victor V. Demidov, Gennady A. Ovsyannikov
Abstract: Magnetic state of epitaxial heterostructures La0.7Sr0.3MnO3/LaMnO3/SrRuO3 (LSMO/LMO/SRO) was studied by SQUID magnetometer, ferromagnetic resonance (FMR) and polarized neutron reflectometry (PNR) techniques. The fit of PNR and FMR data give us the magnetization of each layer, while the SQUID gives the total magnetization of our structures. The magnetic moment of the LMO layer has the magnetization 4πMLMO=4.2kGs (2.4 mB/Mn) at T=140K according to our PNR data fitting.
Authors: Maria Helena Braga, Maria Helena Sá, Jorge A. Ferreira, Luke L. Daemen
Abstract: Density Functional Theory (DFT) calculations were performed. They were firstly implemented to optimize the structure and refine the stoichiometry of the only ternary compound, CuLi0.08Mg1.92 of the Cu-Li-Mg system. Furthermore using DFT, several possible structures of CuMg2Hx were optimized. Since most of the hydrides are cubic structures or can be considered as distortions of a cubic structure, we have started calculations for CuMg2Hx (x = 4 - 6) with tetragonal and monoclinic structures, similar to those of the hydrides formed by the nearest neighbors of Cu and Mg in the periodic table: NiMg2H4 and CoMg2H5 (e.g. monoclinic C2/c and tetragonal P4/nmm, respectively). It can be concluded that the most stable configuration corresponds to CuMg2H5 with C2/c structure. We have performed several neutron scattering experiments that are in agreement with the first principles calculations.
Authors: Vanessa K. Peterson, Cormac Corr, Gordon J. Kearley, Roderick Boswell, Zunbeltz Izaola
Abstract: This paper compares proton diffusion through plasma-polymerised proton-exchange membranes (PEMs) produced using traditional wet-chemical methods (Nafion®) and those produced using plasma-polymerisation. Using quasielastic neutron scattering and a simple model of proton motion we find the measured diffusion-rate of protons in the plasma-polymerised material and Nafion® is the same (within 1 standard error) even though the plasma-polymerised membrane has 80 % less water than the Nafion®. We attribute this result to the highly cross-linked structure of the plasma-polymerised membrane.
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