Microstructure evolution in undercooled Al-8 wt%Fe melts: comparison between terrestrial and parabolic flight conditions

Par Conseil national de recherches du Canada

DOI	Trouver le DOI : https://doi.org/10.1016/j.jallcom.2012.11.182
Auteur	Rechercher : Chen, J.; Rechercher : Lengsdorf, R.; Rechercher : Henein, H.; Rechercher : Herlach, D. M.; Rechercher : Dahlborg, U.; Rechercher : Calvo-Dahlborg, M.
Format	Texte, Article
Sujet	Acicular morphology; Cooling rates; Electromagnetic levitation; Eutectic growth; Hypereutectic alloy; Intermetallic phase; Micro-structure evolutions; Neutron diffraction technique; Non-equilibrium solidification; Nucleation and growth; Parabolic flight; Reduced gravity; Scanning electrons; Solidification condition; Solidification paths; Solidification process; Star-like; Electromagnetic propulsion; Eutectics; Intermetallics; Iron alloys; Levitation melting; Morphology; Neutron diffraction; Scanning electron microscopy; Solidification; Transmission electron microscopy; Undercooling; X ray diffraction; Aluminum
Résumé	Al-8 wt%Fe, a hypereutectic alloy, was studied under electromagnetic levitation (EML) solidification conditions in both terrestrial and reduced gravity conditions. The latter was carried out on the A300 aircraft using the TEMPUS facility. The solidified samples were characterized using scanning electron microscopy, transmission electron microscopy, X-ray diffraction and neutron diffraction techniques. The results are interpreted in the light of the temperature-time measurements taken in situ during the solidification process in the EML. It is shown that both samples experienced some undercooling for the solidification of the primary Al-Fe intermetallic phase, which is likely Al mFe. The solidification path continues with the nucleation and growth of Al13Fe4 followed by primary α-Al. These last two phases do not seem to show any measureable undercooling and recalescence events. Finally, the metastable AlxFe (where x = 5) nucleates starting with the formation of eutectic. This metastable intermetallic continues the eutectic growth as Al13Fe4. The morphology differences of the intermetallics growing under terrestrial and reduced gravity conditions are clear with acicular morphology for the former and a star like morphology for the latter. The primary α-Al has a clear strong textured structure in the reduced gravity sample, while a weak one is observed in the terrestrially processed sample. The difference in texture is attributed to the weaker fluid flow occurring in the droplet under reduced gravity conditions while the difference in the morphology of the primary intermetallic is attributed to the higher cooling rate experienced by the reduced gravity sample compared to that for the terrestrially processed sample. © 2012 Elsevier B.V. All rights reserved.
Date de publication	2013
Dans	Journal of Alloys and Compounds 556 (2013) : 243–251.
Langue	anglais
Publications évaluées par des pairs	Oui
Publication du CNRC	Cette publication n’est pas du CNRC Ce sont des publications qui ont été rédigées par un auteur du CNRC, mais avant que celui-ci soit employé du CNRC.
Numéro NPARC	21271801
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Identificateur de l’enregistrement	518fc7a7-1208-44c0-9892-da756ce3cb9f
Enregistrement créé	2014-04-22
Enregistrement modifié	2020-04-22

Date de modification :: 2024-07-02