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Microstructure evolution and mechanical properties of nanocrystalline FeAl obtained by mechanical alloying and cold consolidation

In the present study high energy mechanical milling followed by cold temperature pressing consolidation has been used to obtain bulk nanocrystalline FeAl alloy. Fully dense disks with homogenous microstructure were obtained and bulk material show grain size of 40 nm. Thermal stability of the bulk material is studied by XRD and DSC techniques. Subsequent annealing at a temperature up to 480 °C for 2 h of the consolidated samples enabled supersaturated Fe(Al) solid solution to precipitate out fine metastable Al5Fe2, Al13Fe4 and Fe3Al intermetallic phases. Low temperature annealing is responsible for the relaxation of the disordered structure by removing defects initially introduced by severe plastic deformation. Microhardness shows an increase with grain size reduction, as expected from Hall-Petch relationship at least down to a grain size of 74 nm, then a decrease at smallest grain sizes. This could be an indication of some softening for finest nanocrystallites. The peak hardening for the bulk nanocrystalline FeAl is detected after isochronal ageing at 480 °C. © 2010 Elsevier B.V. All rights reserved.

Financial support from MICYT MAT2006-13925-C02-02 (FEDER) project is acknowledged.

© Journal of Alloys and Compounds, 2011, vol. 509, p. 3293-3298

Elsevier

Author: Mhadhbi, M.
Khitouni, Mohamed
Escoda i Acero, Ma. Lluïsa
Suñol Martínez, Joan Josep
Dammak, Mohamed Chedly
Date: 2011 February 17
Abstract: In the present study high energy mechanical milling followed by cold temperature pressing consolidation has been used to obtain bulk nanocrystalline FeAl alloy. Fully dense disks with homogenous microstructure were obtained and bulk material show grain size of 40 nm. Thermal stability of the bulk material is studied by XRD and DSC techniques. Subsequent annealing at a temperature up to 480 °C for 2 h of the consolidated samples enabled supersaturated Fe(Al) solid solution to precipitate out fine metastable Al5Fe2, Al13Fe4 and Fe3Al intermetallic phases. Low temperature annealing is responsible for the relaxation of the disordered structure by removing defects initially introduced by severe plastic deformation. Microhardness shows an increase with grain size reduction, as expected from Hall-Petch relationship at least down to a grain size of 74 nm, then a decrease at smallest grain sizes. This could be an indication of some softening for finest nanocrystallites. The peak hardening for the bulk nanocrystalline FeAl is detected after isochronal ageing at 480 °C. © 2010 Elsevier B.V. All rights reserved.
Financial support from MICYT MAT2006-13925-C02-02 (FEDER) project is acknowledged.
Format: application/pdf
ISSN: 0925-8388
Document access: http://hdl.handle.net/10256/12729
Language: eng
Publisher: Elsevier
Collection: MEC/PN 2006-2009/MAT2006-13925-C02-02
Reproducció digital del document publicat a: http://dx.doi.org/10.1016/j.jallcom.2010.10.214
Articles publicats (D-F)
Is part of: © Journal of Alloys and Compounds, 2011, vol. 509, p. 3293-3298
Rights: Tots els drets reservats
Subject: Compostos intermetàl·lics -- Aliatges
Intermetallic compounds -- Alloys
Microestructura
Microstructure
Materials nanoestructurats
Nanostructured materials
Cristal·lografia de raigs X
X-ray crystallography
Materials nanoestructurats -- Propietats mecàniques
Nanostructured materials -- Mechanical properties
Title: Microstructure evolution and mechanical properties of nanocrystalline FeAl obtained by mechanical alloying and cold consolidation
Type: info:eu-repo/semantics/article
Repository: DUGiDocs

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