Publications: Articles
Articles: | |
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Traitements Thermiques,
389:43-46
2008
Equipe: Département SI2M : Microstructures et Contraintes |
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International Journal of Microstructure and Materials Properties,
3(1):150
2008
ISSN: 1741-8429
Equipe: Département SI2M : Microstructures et Contraintes |
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Materials Science and Engineering A,
480:89-95
2008
Equipe: Département SI2M : Microstructures et Contraintes |
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Algerian Journal of Advanced Materials,
5:13
2008
Equipe: Département SI2M : Microstructures et Contraintes |
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MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING,
476(1-2):60-68
2008
ISSN: 0921-5093
Resume: The beta(BCC) -> alpha(HCP) + beta(BCC) phase transformation kinetics of the beta-metastable titanium alloy Ti17 was studied by in situ high energy X-ray diffraction (XRD) and electrical resistivity. The use of synchrotron radiation (E = 89.12 keV, lambda = 0.01402 nm) allowed to characterize specimens 6 mm in diameter, limiting thus oxidation effects. The alpha + beta -> beta phase transformation kinetics was characterized during continuous heating up to the P temperature range. The beta -> alpha + beta transformation was studied in isothermal conditions (dwell at 708 degrees C or 750 degrees C) and during continuous cooling (cooling rates of 0.05 degrees C/s, 0.1 degrees C/s and 0.61 degrees C/s). The evolutions of the phase fractions are analyzed and compared to kinetics measured by electrical resistivity, showing a good correlation between both methods. In addition, the evolutions of the cell parameters of each phase obtained from XRD patterns are analyzed in regard of the transformation kinetics. (C) 2007 Elsevier B.V. All rights reserved. Equipe: Département SI2M : Microstructures et Contraintes |
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Ultramicroscopy,
108 (2)(2):100-115
2008
ISSN: 0304-3991
Resume: By combining the large-angle convergent-beam electron diffraction (LACBED) configuration together with a microscope equipped with a C., corrector it is possible to obtain good quality spot patterns in image mode and not in diffraction mode as it is usually the case. These patterns have two main advantages with respect to the conventional selected-area electron diffraction (SAED) or microdiffraction patterns. They display a much larger number of reflections and the diffracted intensity is the integrated intensity. These patterns have strong similarities with the electron precession patterns and they can be used for various applications like the identification of the possible space groups of a crystal from observations of the Lane zones or the ab-initio structure identifications. Since this is a defocused method, another important application concerns the analysis of electron beam-sensitive materials. Successful applications to polymers are given in the present paper to prove the validity of this method with regards to these materials. (c) 2007 Elsevier B.V. All rights reserved. Equipe: Département SI2M : Microstructures et Contraintes |
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Materials Science and Engineering: A,
487(1-2):33-45
2008
ISSN: 0921-5093
Equipe: Département SI2M : Microstructures et Contraintes |
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COMPUTATIONAL MATERIALS SCIENCE,
42(2):266-280
2008
ISSN: 0927-0256
Resume: A complete modeling of the phase transformation during the cooling following the forging has been carried out for near-beta titanium alloys. To that aim, we have improved a model predicting the influence of the deformation of the beta phase on the alpha phase precipitation during isothermal treatments, by extending its range of application to the case of cooling treatments. In particular, the precipitation of the intragranular morphology alpha(WI) has been introduced. We have proceeded step by step: calculations of heat treatments without any previous forging have first been performed. Then, the influence of the initial beta grain size have been studied. Finally, the influence of a previous deformation coming from the forging has been investigated. At each step, the calculations have been compared to some experiments, showing an good overall agreement. (C) 2007 Elsevier B.V. All rights reserved. Equipe: Département SI2M : Microstructures et Contraintes |