Atomic-scale study of a transition phase precipitate and its interfacial chemistry in an Fe-15 at.% Mo-5 at.% V alloy

Dieter Isheim*, Olof C. Hellman, David N. Seidman, Frédéric Danoix, Alain Bostel, Didier Blavette

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

A Mo-rich precipitate in an Fe-rich matrix and the heterophase interface bounding the precipitate have been examined on an atomic scale by three-dimensional atom-probe (3DAP) microscopy and transmission electron microscopy (TEM). The Mo-rich precipitate was generated by isothermal solid-state decomposition at 500°C of an Fe-15 at.% Mo-5 at.% V alloy. After this heat treatment, TEM reveals a characteristic modulated strain contrast structure. The precipitate has a composition of Mo-13.0 at.% Fe-4.9 at.% V as measured by 3DAP microscopy. The alloy decomposes at a nearly constant 5 at.% V, constituting a metastable tie-line between Fe-rich and Mo-rich bcc solid solutions. The formation of the equilibrium intermetallic phases is kinetically impeded. A local vanadium enrichment of 21 at.% is detected at the interface of the precipitate in a matrix region about 0.27 nm or 1-2 atomic layers in thickness. The corresponding value of the Gibbsian interfacial excess of vanadium is 3.3 ± 1.3 nm-2.

Original languageEnglish (US)
Pages (from-to)424-434
Number of pages11
JournalMicroscopy and Microanalysis
Volume7
Issue number5
StatePublished - Sep 1 2001

Keywords

  • Decomposition
  • Interfacial segregation
  • Iron alloys
  • Three-dimensional atom-probe microscopy

ASJC Scopus subject areas

  • Instrumentation

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