Abstract
γ (fcc) / γ′ (L 12) 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.
Original language | English (US) |
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Article number | 201905 |
Journal | Applied Physics Letters |
Volume | 93 |
Issue number | 20 |
DOIs | |
State | Published - 2008 |
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)