%0 Journal Article
%T In-situ time-resolved study of structural evolutions in a zirconium alloy during high temperature oxidation and cooling
%+ Laboratoire d'Etude du Comportement Mécanique des Matériaux (LC2M)
%+ Institut de Recherche Dupuy de Lôme (IRDL)
%+ Synchrotron SOLEIL (SSOLEIL)
%+ Service de recherches de métallurgie physique (SRMP)
%A Guillou, R.
%A Le Saux, Matthieu
%A Rouesne, E.
%A Hamon, D.
%A Toffolon-Masclet, C.
%A Menut, D.
%A Brachet, Jc
%A Bechade, Jl
%A Thiaudiere, D.
%< avec comité de lecture
%J Materials Characterization
%V 158
%8 2019-12
%D 2019
%R 10.1016/j.matchar.2019.109971
%K Structure
%K XRD
%K Zircaloy-4
%K Oxidation
%K High temperature
%K Zirconia
%Z Engineering Sciences [physics]
%Z Engineering Sciences [physics]/MaterialsJournal articles
%X In-situ time-resolved Synchrotron X-ray diffraction analyses were performed on zirconium alloy (Zircaloy-4) sheet samples, during their heating, isothermal oxidation at 700, 800 and 900 degrees C under a flowing mixture of He and O-2 and cooling. The oxide growth and the evolution of the oxide structure as a function of time and temperature were studied with suitable time resolution. Oxide layer thicknesses of approximately 10 mu m were formed during the experiments. The incident X-rays penetrated the whole oxide thickness. The samples were examined after the experiments by field emission gun scanning electron microscopy, electron backscatter diffraction and electron-probe microanalysis. The results showed that the oxide contains a mixture of monoclinic and tetragonal zirconia evolving during heating, oxidation and cooling. The average volume fraction of tetragonal zirconia decreases during oxidation. This fraction is larger at 900 degrees C than at 700 and 800 degrees C. For oxide layers thinner than approximately 5 mu m, this fraction is larger at 800 degrees C than at 700 degrees C, but it is rather equivalent for both temperatures when the oxide thickness ranges between 5 and 8 mu m. Some of the tetragonal zirconia crystals transforms into the monoclinic phase during cooling after oxidation. This fraction of transformed tetragonal zirconia is larger after oxidation at 900 degrees C than after oxidation at 700 and 800 degrees C. It is suggested that these evolutions of the oxide crystallographic structure are related to micro-stresses and to temperature dependences of the critical size of zirconia crystals below which tetragonal zirconia is stabilized.
%G English
%2 https://hal.science/hal-02431028/document
%2 https://hal.science/hal-02431028/file/S1044580319314731.pdf
%L hal-02431028
%U https://hal.science/hal-02431028
%~ CEA
%~ UNIV-BREST
%~ ENSTA-BRETAGNE
%~ CNRS
%~ UNIV-UBS
%~ UBS
%~ ENIB
%~ DSV
%~ DEN
%~ CEA-UPSAY
%~ IRDL
%~ UNIV-PARIS-SACLAY
%~ CEA-UPSAY-SACLAY
%~ SYNCHROTRON-SOLEIL
%~ CEA-DRF
%~ DEN-SACLAY
%~ ENSTA-BRETAGNE-MECA
%~ TEST-HALCNRS
%~ GS-ENGINEERING
%~ GS-PHYSIQUE
%~ INSTITUT-SCIENCES-LUMIERE
%~ ENSTA-BRETAGNE-PTR5-IRDL
%~ ELSEVIER