Transformations β → ω dans les alliages metalliques du systeme ternaire TiZrO

Dechamps, M.; Lehr, P.; Dubertret, A.; Fayard, M.

doi:10.1016/0025-5408(72)90173-0

Cited by 6 publications

(10 citation statements)

References 2 publications

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“…The Ti-Hf tie line has been studied before but never the entire Ti-Zr-Hf compositional space [13]. There is a coexistence along the two binaries, Ti-Zr (in agreement with [14]) and Ti-Hf, but not along Hf-Zr. Attempts were made to form such Hf-Zr u-phases by varying the temperature of dehydrogenation, but they were not successful.…”

Section: Precursor Materialsmentioning

confidence: 99%

“…The first report of the structure of the u-phase in the Ti-Zr-O system was made by Fykin et al [23,24], who suggested the P6/mmm structure as the uphase alloy, but with O sitting in an octahedral interstice. Later, Déchamps et al performed an extensive study on this material [14].…”

Section: The U-oxidementioning

confidence: 99%

“…The presence of the ''Ti 2 ZrO'' u-oxide is well-established experimentally [13,14,[22][23][24][25][26], although its existence is not widely appreciated. Domagala et al reported a study of the pseudobinary Ti-ZrO 2 phase diagram, showed ZrO 2 to be highly soluble in Ti, and reported the existence of a distinct binary oxide [22].…”

Section: The U-oxidementioning

confidence: 99%

“…As with the metal atoms, L 1 displacive modes affect the O atoms, and only the one subset of such sites in P 3m1,6 i, that does not sit directly on the basal plane of the trigonal cell has nonzero displacement ( Table 2). Mapped further into the P6/mmm phase, this becomes the structure of Fykin [14,23,24]. As in the case of the metal sites, there is an ordering mode of symmetry L 1 between the two O sublattice sites.…”

Section: The Mechanism Of Site Ordering and Displacementmentioning

confidence: 99%

“…Déchamps et al reported a further distortion in stoichiometric Ti 2 ZrO when it is annealed for long periods at low temperature [14]. The resulting lattice is orthorhombic, and the O orders into one of four possible subsites.…”

Section: A Note On the U'(o) Cmmm Phasementioning

confidence: 99%

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Omega-phase in Ti-Hf-Zr alloys produced by the hydride-cycle methodSpecial issue on Neutron Scattering in Canada.

et al. 2010

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Abstract:We report the presence of large proportions of u-phase in Ti-Hf-Zr alloys, prepared using the hydride cycle technique. We show that the u-phase extends across the concentration triangle of Ti-Zr-Hf and report the partitioning of the three metals across the two sites in this structure from neutron and X-ray data. We examine the symmetry of the order parameter governing the b-u phase transition and show that a two-step model for the phase transition involving site ordering followed by displacement is not likely to be correct. We suggest that an interstitial solid solution of oxygen and octahedral vacancies exists, and that the observation of any u-phase diffraction pattern of alloys of these metals at ambient temperature and pressure should be viewed as a potential sign of the presence of oxygen in the octahedral interstitial sites. Résumé : Dans cet article, nous rapportons la présence d'une importante proportion de la phase dite u dans les alliages Ti-Hf-Zr, préparés par une technique de cyclage sous hydrogène (hydride cycle). Nous montrons également que la phase u s'étend à travers le diagramme de concentration triangulaire de Ti-Hf-Zr. De plus, à partir de données de diffractions des neutrons, nous trouvons que les trois métaux se répartissent sur les deux sites distincts dans la structure. Nous examinons la symetrie du paramètre d'ordre qui gouverne la transition de phase b-u et nous montrons qu'un modèle à deux étages pour la transition de phase est improbable. Nous suggérons plutôt la présence d'une solution solide interstitielle d'oxygène et de lacunes octaédriques. De plus, si la phase u est observée dans le diagramme de diffraction d'alliages de ces métaux à température et pression ambiente, on doit la considérer comme un signe possible de la présence d'oxygène sur les sites interstitiels octaédriques.

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Section: Precursor Materialsmentioning

confidence: 99%

Section: The U-oxidementioning

confidence: 99%