Effective interactions and atomic ordering in Ni-rich Ni-Re alloys

He, Shuang; Peng, Ping; Gorbatov, Oleg I.; Ruban, Andrei V.

doi:10.1103/physrevb.94.024111

Cited by 22 publications

(11 citation statements)

References 63 publications

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“…Similarly, nonmagnetic electronic structure calculations of interaction energies between Re atoms in Ni revealed that Re does not tend to form clusters 49 , eliminating another speculation concerning the cause of the Re effect. For the Ni-Re system the results do, however, strongly depend on the magnetic state of the system 50 . In multicomponent systems, the defect formation energy depends on the local chemical environment as well as on the global composition.…”

Section: A Thermodynamic Propertiesmentioning

confidence: 84%

Atomic-scale modeling of superalloys

Hammerschmidt,

Rogal,

Bitzek

et al. 2021

Preprint

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Atomistic theory holds the promise for the ab initio development of superalloys based on the fundamental principles of quantum mechanics. The last years showed a rapid progress in the field. Results from atomistic modeling enter larger-scale simulations of alloy performance and often may be compared directly to experimental characterization. In this chapter we give an overview of atomistic modeling and simulation for Ni-base superalloys. We cover descriptions of the interatomic interaction from quantum-mechanical simulations with a small number of atoms to multi-millionatom simulations with classical interatomic potentials. Methods to determine structural stability for different chemical compositions, thermodynamic and kinetic properties of typical defects in superalloys, and relations to mechanical deformation are discussed. Connections to other modeling techniques are outlined.

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Section: A Thermodynamic Propertiesmentioning

confidence: 84%

Atomic-scale modeling of superalloys

Hammerschmidt,

Rogal,

Bitzek

et al. 2021

Preprint

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“…In this study, considering atomic interactions in face-centered cubic (fcc) Ni matrix [ 27 ], we obtain the atomic interactions from a set of the total energies of supercells where positions in a given cluster are occupied by atoms in different configurations. These were calculated from two representative cases: In the binary system of Ni–X, the X–X solute pair interaction at the p th coordination shell is calculated by [ 27 ]:

where

is the total energy of a supercell with two X atoms at the p th coordination shell,

is the total energy of a supercell with one X atom, and

is the total energy with no impurity; In the ternary system of Ni–X–Y, the X–Y solute pair interaction in the p th coordination shell is calculated by:

where

is the total energy of a supercell with two Y atoms at the p th coordination shell, and

is the total energy of the supercell with one X atom and one Y atom at the p th coordination shell. In this work, a negative interaction energy indicates the attraction between solutes.…”

Section: Methodsmentioning

confidence: 99%

“…In the binary system of Ni–X, the X–X solute pair interaction at the p th coordination shell is calculated by [ 27 ]:

where

is the total energy of a supercell with two X atoms at the p th coordination shell,

is the total energy of a supercell with one X atom, and

is the total energy with no impurity;…”

Section: Methodsmentioning

confidence: 99%

Atomic Interactions and Order–Disorder Transition in FCC-Type FeCoNiAl1−xTix High-Entropy Alloys

Zhou

Feng

et al. 2022

Materials

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Single-phase high-entropy alloys with compositionally disordered elemental arrangements have excellent strength, but show a serious embrittlement effect with increasing strength. Precipitation-hardened high-entropy alloys, such as those strengthened by L12-type ordered intermetallics, possess a superior synergy of strength and ductility. In this work, we employ first-principles calculations and thermodynamic simulations to explore the atomic interactions and order–disorder transitions in FeCoNiAl1−xTix high-entropy alloys. Our calculated results indicate that the atomic interactions depend on the atomic size of the alloy components. The thermodynamic stability behaviors of L12 binary intermetallics are quite diverse, while their atomic arrangements are short-range in FeCoNiAl1−xTix high-entropy alloys. Moreover, the order–disorder transition temperatures decrease with increasing Ti content in FeCoNiAl1−xTix high-entropy alloys, the characteristics of order–disorder transition from first-principles calculations are in line with experimental observations and CALPHAD simulations. The results of this work provide a technique strategy for proper control of the order–disorder transitions that can be used for further optimizing the microstructure characteristics as well as the mechanical properties of FeCoNiAl1−xTix high-entropy alloys.

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“…All calculations were carried out spin-polarized as it was shown that magnetism significantly influences the interactions between solute atoms in Ni, in particular for Re. 44 The diffusion barriers were determined using the climbing-image nudged-elastic band (CI-NEB) method [45][46][47] as provided by the VTST package 48 for VASP. Calculations were performed in (3 × 3 × 3) fcc supercells with a [4 × 4 × 4] Monkhorst-Pack 49 k-point mesh and a plane wave cutoff of 560 eV for the Ni-Re system and 500 eV for the Ni-W and Ni-Ta system.…”

Section: B Density Functional Theory Calculationsmentioning

confidence: 99%

Kinetic Monte Carlo simulations of vacancy diffusion in non-dilute Ni-X (X=Re,W,Ta) alloys

Grabowski¹,

Rogal²,

Drautz³

2018

Preprint

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The mobility of vacancies in alloys may limit dislocation climb. Using a combined density functional theory and kinetic Monte Carlo approach we investigate vacancy diffusion in Ni-Re, Ni-W, and Ni-Ta binary alloys up to 10 at.% solute concentration. We introduce an interaction model that takes into account the chemical environment close to the diffusing atom to capture the effect of solute-host and solute-solute interactions on the diffusion barriers. In contrast to an ideal solid solution it is not only the diffusion barrier of the solute atom that influences the vacancy mobility, but primarily the change in the host diffusion barriers due to the presence of solute atoms. This is evidenced by the fact that the observed vacancy slowdown as a function of solute concentration is larger in Ni-W than in Ni-Re, even though Re is a slower diffuser than W. To model diffusion in complex, non-dilute alloys an explicit treatment of interaction energies is thus unavoidable. In the context of Ni-based superalloys two conclusions can be drawn from our kinetic Monte Carlo simulations: the observed slowdown in vacancy mobility is not sufficient to be the sole cause for the so-called Re-effect; and assuming a direct correlation between vacancy mobility, dislocation climb, and creep strength the experimentally observed similar effect of W and Re in enhancing creep strength can be confirmed.

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Effective interactions and atomic ordering in Ni-rich Ni-Re alloys

Cited by 22 publications

References 63 publications

Atomic-scale modeling of superalloys

Atomic-scale modeling of superalloys

Atomic Interactions and Order–Disorder Transition in FCC-Type FeCoNiAl1−xTix High-Entropy Alloys

Kinetic Monte Carlo simulations of vacancy diffusion in non-dilute Ni-X (X=Re,W,Ta) alloys

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