TY - JOUR
T1 - Segregation of tungsten at γ′ (L 12) /γ (fcc) interfaces in a Ni-based superalloy
T2 - An atom-probe tomographic and first-principles study
AU - Amouyal, Yaron
AU - Mao, Zugang
AU - Seidman, David N.
N1 - Funding Information:
The research was implemented in support of MEANS II AFOSR under Grant No. FA9550-05-1-0089. Y.A. wishes to acknowledge the Marie Curie IOF (CEC FP7). Dr. L. Graham and Professor T. Pollock are kindly thanked for supplying alloys. The LEAP tomograph was purchased with funding from the NSF-MRI and ONR-DURIP programs. The authors wish to acknowledge Dr. D. Isheim for managing the Northwestern University Center for Atom-Probe Tomography (NUCAPT), and Mr. C. Booth-Morrison and Dr. J. Wu (EPIC) of Northwestern University for helpful discussions.
PY - 2008
Y1 - 2008
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=56849106492&partnerID=8YFLogxK
U2 - 10.1063/1.3026745
DO - 10.1063/1.3026745
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AN - SCOPUS:56849106492
SN - 0003-6951
VL - 93
JO - Applied Physics Letters
JF - Applied Physics Letters
IS - 20
M1 - 201905
ER -