Papers by Keyword: Line Profile Analysis

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Authors: Ádám Révész, L. Nagy, Gábor Ribárik, Zsolt Kovács, Tamás Ungár, Janos Lendvai
Authors: J. Bednarčík, R. Nicula, Karel Saksl, M. Stir, E. Burkel
Abstract: The magnetic, mechanical or chemical properties of nanocrystalline materials strongly differ from the ones of their coarse-grained counterparts. Moreover, significant changes of the phase diagrams were already evidenced for nanostructured alloys. Thermal processing with or without applied pressure controls the microstructure development at the nanometer scale and thus essentially decides upon the final nanomaterial behaviour and properties. A common route for the synthesis of metallic nanomaterials is the devitrification of amorphous precursors obtained via non-equilibrium processing, e.g. by rapid solidification or high-energy ball-milling. Time-resolved in-situ X-ray diffraction experiments may nowadays be performed at high-brilliance synchrotron radiation sources for a variety of temperature-pressure conditions. The temperature-time evolution of the grain-size distribution and microstrain can be monitored in detail at specimen-relevant scales. Together with local information from electron microscopy and chemical analysis, in-situ X-ray experiments offer a complete set of tools for engineering of the microstructure in nanomaterials. The effect of individual processing steps can be distinguished clearly and further tuned. An example is provided, concerning the high-temperature microstructure development in Co-rich soft magnetic nanostructured alloys.
Authors: Kenneth R. Beyerlein, Matteo Leoni, Robert L. Snyder, Paolo Scardi
Abstract: Patterns calculated by applying the Debye function to faulted spherical nanoparticles are used to test the accuracy of modern Line Profile Analysis theory of faulting for small crystallites. The relative deviation of the determined fault density is found to be dependent on the fault position, and on the particle size. The study of the average pattern from systems of 100 particles (D = 9.8nm) shows an overestimated deviation of the determined fault density by as much as 30%.
Authors: Paolo Scardi, Matteo Leoni, D. Dodoo-Arhin
Abstract: Recent advances in Line Profile Analysis of powder diffraction patterns must be paralleled by increasing attention to the quality and quantity of experimental data. The analysis of simulated data with different noise levels demonstrates the importance of statistical quality to reveal fine details of interest in the analysis of nanocrystalline materials, like the crystallite shape. It is also shown how synchrotron radiation diffraction can improve data quality with respect to laboratory measurements, both in terms of statistical quality and in terms of accessible information.
Authors: Olivier Castelnau, Tamás Ungár, A. Miroux, Thierry Chauveau, Brigitte Bacroix
Authors: Francisco Manuel Braz Fernandes, Rui Jorge C. Silva
Authors: Olivier Castelnau, Thierry Chauveau, M. Drakopoulos, A.A. Snigirev, I. Snigireva, C. Schroer, Tamás Ungár
Authors: Alexandre Boulle, C. Legrand, P. Thomas, R. Guinebretière, J.P. Mercurio, A. Dauger
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