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2019-12-13 - Colloque/Présentation - poster - Anglais - page(s)

Signe Goumwe Stella , Gonon Maurice , Demuynck Maryse , Erauw Jean-Pierre, Mitshiabu Landry, Aubry Philippe, Dupont Vedi, "Evaluation of Rietveld method applied to XRD patterns for microstructural characterization of MAX-phases" in BCerS Annual Meeting , Liège, Belgique, 2018

  • Codes CREF : Matériaux céramiques et poudres (DI2744)
  • Unités de recherche UMONS : Science des Matériaux (F502)
  • Instituts UMONS : Institut de Recherche en Science et Ingénierie des Matériaux (Matériaux)
  • Centres UMONS : Ingénierie des matériaux (CRIM)
Texte intégral :

Abstract(s) :

(Anglais) « MAX phases » are a very important and interesting class of layered ternary carbides and nitrides, thanks to their unusual properties that combine both those of metals and ceramics. Among all MAX phases synthetized nowadays, Ti2AlC and Ti3AlC2 are distinguishable by their exceptional oxidation resistant properties [1]. To produce optimized MAX phases samples, it is important to be able to provide a complete and reliable microstructural characterization of this materials after synthesis. In the present work, we evaluate the reliability of Rietveld refinement technic applied to XRD patterns as a tool for microstructural investigation of Spark Plasma Sintered MAX phases of Ti-Al-C system. In this order, microstructural characteristics including (00l) preferred orientation, weight and crystallite size of SPS synthesized Ti2AlC/Ti3AlC2 MAX phases powders have been investigated. For Rietveld refinement, calculations have been performed in MAUD software and the reliability of calculations has been examined in terms of repeatability and reproducibility of measurements. Results show that accuracy of results are strongly link to the fact to considering (00l) preferential orientation phenomena during calculations, as MAX Phases are lamellar compounds. Moreover, the determination of P00l factor (multiplicity of the (00l) lattice planes with respect to the random orientation) strongly depends on the chosen calculation model (March-Dollase/Standard functions). A rather good repeatability and reproducibility of texture and weight fractions calculations has been noticed although an effect of the preparation sample is underlined (orientation of crystallites in the holder is a function of the way of pressing powders). Crystallites size for its part are less repeatable and reproducible.