TITLE

Segregation of tungsten at γ′(L12)/γ(fcc) interfaces in a Ni-based superalloy: An atom-probe tomographic and first-principles study

AUTHOR(S)
Amouyal, Yaron; Zugang Mao; Seidman, David N.
PUB. DATE
November 2008
SOURCE
Applied Physics Letters;11/17/2008, Vol. 93 Issue 20, p201905
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
γ(fcc)/γ′(L12) heterophase interfaces in a Ni-based superalloy are investigated using atom-probe tomography and first-principles calculations. Flat {100} interfaces exhibit a confined (nonmonotonic) Gibbsian interfacial excess of tungsten, ΓW=1.2±0.2 nm-2, corresponding to a 5 mJ m-2 decrease in interfacial free energy. Conversely, no measurable segregation of W is detected at curved interfaces. First-principles calculations for a Ni–Al–W system having a {100} interface indicate a decrease in the interfacial energy of 5 mJ m-2 due to W segregation. Similar calculations for {110} and {111} interfaces predict an increase of 1 and 9 mJ m-2 in their energies, respectively, and therefore no heterophase segregation.
ACCESSION #
35514096

 

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