Time evolution of morphology in mechanically alloyed Fe-Cu

Handle URI:
http://hdl.handle.net/10754/561769
Title:
Time evolution of morphology in mechanically alloyed Fe-Cu
Authors:
Wille, Catharina Gabriele; Al-Kassab, Talaát; Kirchheim, Reiner
Abstract:
Being widely accessible as well as already utilised in many applications, Fe-Cu acts as an ideal binary model alloy to elaborate the enforced nonequilibrium enhanced solubility in such a solution system that shows a limited regime of miscibility and characterised by a large positive heat of mixing. In addition to the detailed analysis of ball milled Fe-Cu powders by means of Atom Probe Tomography (APT), site specific structural analysis has been performed in this study using Transmission Electron Microscopy (TEM).In this contribution results on powders with low Cu concentrations (2.5-10 at%) are presented. Combining a ductile element (Cu, fcc) and a brittle one (Fe, bcc), striking differences in morphology were expected and found on all length-scales, depending on the mixing ratio of the two elements. However, not only could the atomic mixing of Fe and Cu be evaluated, but also the distribution of impurities, mostly stemming from the fabrication procedure. The combination of APT and TEM enables a correlation between the structural evolution and the chemical mixing during the milling process. For the first time, a clear distinction can be drawn between the morphological evolution at the surface and in the interior of the powder particles. This became possible owing to the site specific sample preparation of TEM lamellae by Focussed Ion Beam (FIB). Surprisingly, the texture arising from the ball milling process can directly be related to the classical rolling texture of cold rolled Fe. In addition, full homogeneity can be achieved even on the nano-scale for this material as shown by APT, resulting in an extended miscibility region in comparison to the equilibrium phase diagram. Grain sizes were determined by means of XRD and TEM. The strain corrected XRD results are in very good agreement with the values derived by TEM, both confirming a truly nanocrystalline structure. © 2011 Elsevier B.V.
KAUST Department:
Materials Science and Engineering Program; Physical Sciences and Engineering (PSE) Division
Publisher:
Elsevier
Journal:
Ultramicroscopy
Issue Date:
May-2011
DOI:
10.1016/j.ultramic.2011.01.036
Type:
Article
ISSN:
03043991
Sponsors:
Financial support from the Deutsche Forschungsgemeinschaft for a bi-national German (University of Goettingen)/South Korean (University of Ulsan) cooperation under the contract KI-230/33-1 is gratefully acknowledged.
Appears in Collections:
Articles; Physical Sciences and Engineering (PSE) Division; Materials Science and Engineering Program

Full metadata record

DC FieldValue Language
dc.contributor.authorWille, Catharina Gabrieleen
dc.contributor.authorAl-Kassab, Talaáten
dc.contributor.authorKirchheim, Reineren
dc.date.accessioned2015-08-03T09:04:11Zen
dc.date.available2015-08-03T09:04:11Zen
dc.date.issued2011-05en
dc.identifier.issn03043991en
dc.identifier.doi10.1016/j.ultramic.2011.01.036en
dc.identifier.urihttp://hdl.handle.net/10754/561769en
dc.description.abstractBeing widely accessible as well as already utilised in many applications, Fe-Cu acts as an ideal binary model alloy to elaborate the enforced nonequilibrium enhanced solubility in such a solution system that shows a limited regime of miscibility and characterised by a large positive heat of mixing. In addition to the detailed analysis of ball milled Fe-Cu powders by means of Atom Probe Tomography (APT), site specific structural analysis has been performed in this study using Transmission Electron Microscopy (TEM).In this contribution results on powders with low Cu concentrations (2.5-10 at%) are presented. Combining a ductile element (Cu, fcc) and a brittle one (Fe, bcc), striking differences in morphology were expected and found on all length-scales, depending on the mixing ratio of the two elements. However, not only could the atomic mixing of Fe and Cu be evaluated, but also the distribution of impurities, mostly stemming from the fabrication procedure. The combination of APT and TEM enables a correlation between the structural evolution and the chemical mixing during the milling process. For the first time, a clear distinction can be drawn between the morphological evolution at the surface and in the interior of the powder particles. This became possible owing to the site specific sample preparation of TEM lamellae by Focussed Ion Beam (FIB). Surprisingly, the texture arising from the ball milling process can directly be related to the classical rolling texture of cold rolled Fe. In addition, full homogeneity can be achieved even on the nano-scale for this material as shown by APT, resulting in an extended miscibility region in comparison to the equilibrium phase diagram. Grain sizes were determined by means of XRD and TEM. The strain corrected XRD results are in very good agreement with the values derived by TEM, both confirming a truly nanocrystalline structure. © 2011 Elsevier B.V.en
dc.description.sponsorshipFinancial support from the Deutsche Forschungsgemeinschaft for a bi-national German (University of Goettingen)/South Korean (University of Ulsan) cooperation under the contract KI-230/33-1 is gratefully acknowledged.en
dc.publisherElsevieren
dc.subjectAtom probe tomography (APT)en
dc.subjectFe-Cuen
dc.subjectMechanical alloyingen
dc.subjectNanocrystallineen
dc.subjectPowdersen
dc.subjectTransmission electron microscopy (TEM)en
dc.titleTime evolution of morphology in mechanically alloyed Fe-Cuen
dc.typeArticleen
dc.contributor.departmentMaterials Science and Engineering Programen
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.identifier.journalUltramicroscopyen
dc.contributor.institutionInstitute for Materials Physics, Georg-August-University Goettingen, Friedrich-Hund-Platz 1, 37077 Goettingen, Germanyen
kaust.authorWille, Catharina Gabrieleen
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