Title :

Microstructural effects and mechanism of bcc-hcp-bcc transformations in polycrystalline iron

Author(s) :

Merkel, Sébastien [Auteur]
Unité Matériaux et Transformations - UMR 8207 [UMET]
Lincot, Ainhoa [Auteur]
Institut des Sciences de la Terre [ISTerre]
Petitgirard, Sylvain [Auteur]
European Synchrotron Radiation Facility [ESRF]

Journal title :

Physical Review B

Volume number :

102

Pages :

104103

Publication date :

2020-09-11

HAL domain(s) :

Chimie/Matériaux
Physique [physics]/Matière Condensée [cond-mat]/Science des matériaux [cond-mat.mtrl-sci]
Physique [physics]/Physique [physics]/Géophysique [physics.geo-ph]
Physique [physics]/Astrophysique [astro-ph]
Planète et Univers [physics]/Astrophysique [astro-ph]
Planète et Univers [physics]/Sciences de la Terre

English abstract : [en]

Cycling the α↔ε transformation in polycrystalline Fe is investigated using in situ x-ray diffraction under quasihydrostatic conditions. The forward α→ε transformation starts at 14±1 GPa and completes at 18±1 GPa while the ...
Show more >Cycling the α↔ε transformation in polycrystalline Fe is investigated using in situ x-ray diffraction under quasihydrostatic conditions. The forward α→ε transformation starts at 14±1 GPa and completes at 18±1 GPa while the reverse ε→α transformation starts at 10.5±0.5 GPa and completes at 6±1 GPa. The anomalous evolution of c/a ratios of ε-Fe measured at the onset of the α→ε transition in earlier studies is not observed. Microstructural features are consistent with a Burgers path for the transformation. The forward α→ε transformation is sensitive to the average and intergranular stresses, inducing a strong variant selection with the c axes of the new ε phase preferentially aligned perpendicular to compression and concentrated into one single orientation. Partial texture memory is observed as the sample returns to the α phase but, as transformation cycles go on, irreversible changes occur in the microstructures that are later fully induced by the cycles of phase transformations.Show less >

Language :

Anglais

Peer reviewed article :

Oui

Audience :

Internationale

Popular science :

Non

Administrative institution(s) :

Université de Lille
CNRS
INRA
ENSCL

Collections :

• Unité Matériaux et Transformations (UMET) - UMR 8207

Research team(s) :

Matériaux Terrestres et Planétaires

Submission date :

2020-09-11T16:06:34Z
2020-09-12T08:00:07Z
2020-09-12T14:06:06Z
2020-09-14T10:07:11Z