TY - JOUR
T1 - Combined atom probe tomography and first-principles calculations for studying atomistic interactions between tungsten and tantalum in nickel-based alloys
AU - Amouyal, Yaron
AU - Mao, Zugang
AU - Seidman, David N.
N1 - Funding Information:
This research was supported by MEANS II AFOSR, Grant No. FA9550-05-1-0089, and the National Science Foundation (NSF) – USA , Grant No. DMR-0804610 , for Z.M.’s work. Y.A. wishes to acknowledge the Marie Curie IOF support under the 7th framework program of the commission of the European community. Dr. Larry Graham (PCC Airfoils) and Prof. Tresa Pollock (University of California, Santa Barbara) are kindly thanked for supplying alloys. The authors wish to thank Dr. Ronald D. Noebe for aging alloys and Dr. Chantal K. Sudbrack (NASA Glenn Research Center, Cleveland OH) for performing JMatPro calculations. Atom probe tomographic measurements were performed in the Northwestern University Center for Atom-Probe Tomography (NUCAPT). The LEAP tomograph was purchased and upgraded with funding from NSF-MRI (DMR-0420532, Dr. Charles Bouldin, grant officer) and ONR-DURIP (N00014-0400798, N00014-0610539, N00014-0910781, Dr. Julie Cristodoulou, grant officer) grants. The authors also wish to thank Dr. Dieter Isheim for managing NUCAPT, as well as Dr. Chris Booth-Morrison and Mr. Jeff W. Doak (Northwestern University), Prof. Donald J. Siegel (University of Michigan, Ann Arbor) and Dr. Alexander Katsman (Department of Materials Science & Engineering, Technion) for helpful discussions.
PY - 2014/8/1
Y1 - 2014/8/1
N2 - We investigate the partitioning behavior of tungsten to the γ(face-centered cubic) and γ′(L12) phases in Ni-based alloys employing atom probe tomography (APT), first-principles calculations and computational thermodynamics. Several APT studies of Ni-based alloys indicate that the partitioning of tungsten atoms to the γ′(L12) phase is reversed in favor of the γ phase due to tantalum atom additions. First-principles calculations of substitutional formation energies at 0 K indicate that tungsten and tantalum atoms share the aluminum sublattice sites of the γ′(L12) phase, and that tantalum has a larger tendency to partition to the γ′(L1 2) phase than does W. We also calculate the binding energies of W-W and Ta-W dimers in the γ(fcc) and γ′(L12) phases, respectively, and use these values in a quantitative model to demonstrate that interatomic interactions between tungsten and tantalum atoms play a significant role in the partitioning reversal of tungsten.
AB - We investigate the partitioning behavior of tungsten to the γ(face-centered cubic) and γ′(L12) phases in Ni-based alloys employing atom probe tomography (APT), first-principles calculations and computational thermodynamics. Several APT studies of Ni-based alloys indicate that the partitioning of tungsten atoms to the γ′(L12) phase is reversed in favor of the γ phase due to tantalum atom additions. First-principles calculations of substitutional formation energies at 0 K indicate that tungsten and tantalum atoms share the aluminum sublattice sites of the γ′(L12) phase, and that tantalum has a larger tendency to partition to the γ′(L1 2) phase than does W. We also calculate the binding energies of W-W and Ta-W dimers in the γ(fcc) and γ′(L12) phases, respectively, and use these values in a quantitative model to demonstrate that interatomic interactions between tungsten and tantalum atoms play a significant role in the partitioning reversal of tungsten.
KW - Atom probe tomography
KW - Binding energy
KW - First-principles calculations
KW - Ni-based superalloys
KW - Partitioning ratio
UR - http://www.scopus.com/inward/record.url?scp=84900971912&partnerID=8YFLogxK
U2 - 10.1016/j.actamat.2014.03.064
DO - 10.1016/j.actamat.2014.03.064
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AN - SCOPUS:84900971912
SN - 1359-6454
VL - 74
SP - 296
EP - 308
JO - Acta Materialia
JF - Acta Materialia
ER -