Publications: Articles
2008 | |
Articles: | |
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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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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 |
2007 | |
Articles: | |
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Journal of Materials,
59(1):54-58
2007
ISSN: 1047-4838
Resume: The prediction of microstructure during processing needs to characterize the phase transformation occurring during the thermal treatments and their kinetics. In-situ high-energy synchrotron x-ray diffraction experiments performed during temperature variations allow the characterization of the phase evolution. For some transformation conditions, the continuous recording of diffraction diagrams evidences clearly intermediate phases. The quantitative analysis of the diffraction diagrams gives the transformation kinetics of each phase as well as their cell parameters. Transformation kinetics obtained by this method are compared to results obtained by electrical resistivity. Equipe: Département SI2M : Département SI2M : Microstructures et Contraintes |
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MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING,
448(1-2):135-145
2007
ISSN: 0921-5093
Resume: We have investigated the microstructure evolutions in the Ti17 near beta titanium alloy during heat treatments. The phase transformation has first been studied experimentally by combining X-ray diffraction analysis, electrical resistivity and microscopy observations. From a series of isothermal treatments. a IT diauram has been determined, which takes into account the different morphologies. Then, a Johnson-Mehl-Avrami-Kolmogorov (JMAK) model has been successfully used to describe the phase transformation kinetics during either isothermal or cooling treatments. Finally, the coupling of the JMAK model to the finite element software ZeBuLoN allowed us to investigate the evolution of the spatial distribution of the different morphologies during the cooling of an aircraft engine shaft disk after forging. (c) 2006 Elsevier B.V. All rights reserved. Equipe: Département SI2M : Microstructures et Contraintes |