Atomistic simulations of stainless steels: a many-body potential for the Fe–Cr–C system

The Fe-Cu-Ni ternary alloy is of interest for nuclear applications because Cu and Ni are considered to have major effects on the embrittlement under irradiation of reactor pressure vessel steels. To improve our understanding on this phenomenon, large scale atomistic simulations in this model alloy are desirable. For this purpose we develop a ternary Fe-Cu-Ni many-body potential consistent with thermodynamics is developed for the first time. The potential was validated using molecular static and atomistic kinetic Monte Carlo simulations and a qualitative agreement with experiments was established. In particular, Cu precipitates were found to be enriched by Ni on the precipitate surface. Also, the effects diluting the Fe-Cu alloy by Ni on mean precipitate size and density showed similar trends as observed in experiments; i.e. no effect of Ni on the mean precipitate size and an increase in the maximum precipitate density due to the addition of Ni. In absolute terms, agreement with experiment is poor due to the limited box size used in the simulations, as correspondingly discussed.

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Experimental and theoretical investigation of the order-disorder transformation in Ni3Al

Journal of Materials Research ◽

10.1557/jmr.1993.2504 ◽

1993 ◽

Vol 8 (10) ◽

pp. 2504-2509 ◽

Cited By ~ 35

Author(s):

Francesco Cardellini ◽

Fabrizio Cleri ◽

Giorgio Mazzone ◽

Amelia Montone ◽

Vittorio Rosato

Keyword(s):

Atomistic Simulations ◽

Many Body ◽

Scanning Calorimetry ◽

X Ray ◽

Disordered Phase ◽

Migration Mechanism ◽

Extended Range ◽

The Stability ◽

Body Potential ◽

Scanning Electron

The crystalline disordered phase obtained by mechanical alloying of elemental 75 at. % Ni and 25 at. % Al powders has been investigated. The stability of this phase with respect to the thermal reordering process leading to the L12 structure has been analyzed by means of x-ray diffractometry, scanning electron microscopy, and differential scanning calorimetry. Atomistic simulations on an Ni3Al model, reproduced via molecular dynamics using a many-body potential, have been used to interpret experimental data. The ordering transformation takes place in an extended range of temperature (from 320 to 600 °C) and occurs simultaneously with the release of internal strain. Numerical simulations performed under different conditions show that the activation energy of the Ni-vacancy migration mechanism responsible for the ordering process depends on the local state of strain, thus suggesting an explanation for the considerable lowering of this energy in samples obtained by ball milling.

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Accurate Interatomic Potentials for Ni, Al and Ni3Al

MRS Proceedings ◽

10.1557/proc-82-175 ◽

1986 ◽

Vol 82 ◽

Cited By ~ 472

Author(s):

Arthur F. Voter ◽

Shao Ping Chen

Keyword(s):

Interatomic Potential ◽

Alloy System ◽

Atomistic Simulations ◽

Al Alloy ◽

Interatomic Potentials ◽

Many Body ◽

Fitting Procedure ◽

Crack Tips ◽

Computational Dependence ◽

Body Potential

ABSTRACTTo obtain meaningful results from atomistic simulations of materials, the interatomic potentials must be capable of reproducing the thermodynamic properties of the system of interest. Pairwise potentials have known deficiencies that make them unsuitable for quantitative investigations of defective regions such as crack tips and free surfaces. Daw and Baskes [Phys. Rev. B 29, 6443 (1984)] have shown that including a local “volume” term for each atom gives the necessary many-body character without the severe computational dependence of explicit n-body potential terms. Using a similar approach, we have fit an interatomic potential to the Ni3Al alloy system. This potential can treat diatomic Ni2, diatomic Al2, fcc Ni, fcc Al and L12 Ni3Al on an equal footing. Details of the fitting procedure are presented, along with the calculation of some properties not included in the fit.

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Data-Driven Many-Body Models with Chemical Accuracy for CH4/H2O Mixtures

10.26434/chemrxiv.13013057 ◽

2020 ◽

Author(s):

Marc Riera ◽

Alan Hirales ◽

Raja Ghosh ◽

Francesco Paesani

Keyword(s):

Liquid Phase ◽

Quantitative Description ◽

Liquid Mixtures ◽

Many Body ◽

Energy Functions ◽

Potential Energy Functions ◽

Dynamics Simulations ◽

Body Potential ◽

Small Clusters ◽

Many Body Interactions

<div> <div> <div> <p>Many-body potential energy functions (PEFs) based on the TTM-nrg and MB-nrg theoretical/computational frameworks are developed from coupled cluster reference data for neat methane and mixed methane/water systems. It is shown that that the MB-nrg PEFs achieve subchemical accuracy in the representation of individual many-body effects in small clusters and enables predictive simulations from the gas to the liquid phase. Analysis of structural properties calculated from molecular dynamics simulations of liquid methane and methane/water mixtures using both TTM-nrg and MB-nrg PEFs indicates that, while accounting for polarization effects is important for a correct description of many-body interactions in the liquid phase, an accurate representation of short-range interactions, as provided by the MB-nrg PEFs, is necessary for a quantitative description of the local solvation structure in liquid mixtures. </p> </div> </div> </div>

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The phase diagram of carbon dioxide from correlation functions and a many-body potential

The Journal of Chemical Physics ◽

10.1063/5.0054314 ◽

2021 ◽

Vol 155 (2) ◽

pp. 024503

Author(s):

Amanda A. Chen ◽

Alexandria Do ◽

Tod A. Pascal

Keyword(s):

Carbon Dioxide ◽

Phase Diagram ◽

Correlation Functions ◽

Many Body ◽

Body Potential

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$$\hbox {Ag}_{m} \hbox {Rh}_n$$ clusters with $$m+n\le 55$$

Theoretical Chemistry Accounts ◽

10.1007/s00214-021-02736-x ◽

2021 ◽

Vol 140 (4) ◽

Author(s):

Nicolas Louis ◽

Stephan Kohaut ◽

Michael Springborg

Keyword(s):

Genetic Algorithms ◽

Structure Optimization ◽

Structural Similarity ◽

Similarity Function ◽

Many Body ◽

Coordination Numbers ◽

Energetic Properties ◽

Ag Clusters ◽

Body Potential ◽

Mixed Clusters

AbstractUsing a combination of genetic algorithms for the unbiased structure optimization and a Gupta many-body potential for the calculation of the energetic properties of a given structure, we determine the putative total-energy minima for all $$\hbox {Ag}_{m} \hbox {Rh}_n$$ Ag m Rh n clusters with a total number of atoms $$m+n$$ m + n up to 55. Subsequently, we use various descriptors to analyze the obtained structural and energetic properties. With the help of a similarity function, we show that the pure Ag and Rh clusters are structurally similar for sizes up to around 20 atoms. The same approach gives that the mixed clusters tend to possess a larger structural similarity with the pure Rh clusters than with the pure Ag clusters. However, for clusters with $$m\simeq n\ge 25$$ m ≃ n ≥ 25 , other structures dominate. The effective coordination numbers for the Ag and Rh atoms as well as the radial distributions of those atoms indicate that there is a tendency towards segregation with Rh atoms forming an inner part and the Ag atoms forming a shell. Only few clusters, all with a fairly large total number of atoms, are found to be particularly stable.

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Dislocation Generation and Crack Propagation in Metals Examined in Molecular Dynamics Simulations

MRS Proceedings ◽

10.1557/proc-278-173 ◽

1992 ◽

Vol 278 ◽

Cited By ~ 6

Author(s):

J. A. Rifkin ◽

C. S. Becquart ◽

D. Kim ◽

P. C. Clapp

Keyword(s):

Crack Propagation ◽

Atomistic Simulations ◽

Many Body ◽

Dislocation Generation ◽

Embedded Atom ◽

Stress Levels ◽

Different Temperatures ◽

The Many ◽

Dynamics Simulations ◽

Many Body Interactions

AbstractWe have carried out a series of atomistic simulations on arrays of about 10,000 atoms containing an atomically sharp crack and subjected to increasing stress levels. The ordered stoichiometric alloys B2 NiAl, B2 RuAl and A15 Nb3AI have been studied at different temperatures and stress levels, as well as the elements Al, Ni, Nb and Ru. The many body interactions used in the simulations were derived semi-empirically, using techniques related to the Embedded Atom Method. Trends in dislocation generation rates and crack propagation modes will be discussed and compared to experimental indications where possible, and some of the simulations will be demonstrated in the form of computer movies.

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Ternary Fe–Cu–Ni many-body potential to model reactor pressure vessel steels: First validation by simulated thermal annealing

The Philosophical Magazine A Journal of Theoretical Experimental and Applied Physics ◽

10.1080/14786430903299824 ◽

2009 ◽

Vol 89 (34-36) ◽

pp. 3531-3546 ◽

Cited By ~ 141

Author(s):

G. Bonny ◽

R.C. Pasianot ◽

N. Castin ◽

L. Malerba

Keyword(s):

Thermal Annealing ◽

Pressure Vessel ◽

Reactor Pressure Vessel ◽

Many Body ◽

Pressure Vessel Steels ◽

Body Potential ◽

Reactor Pressure

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Mechanical and Tribological Properties of Carbon Nanotubes Investigated with Atomistic Simulations

MRS Proceedings ◽

10.1557/proc-633-a17.3 ◽

2000 ◽

Vol 633 ◽

Author(s):

Boris Ni ◽

Susan B. Sinnott

Keyword(s):

Carbon Nanotubes ◽

Atomistic Simulations ◽

Many Body ◽

Jones Potential ◽

Diamond Surfaces ◽

Empirical Potential ◽

Mechanical And Tribological Properties ◽

Lennard Jones ◽

Walled Carbon Nanotubes ◽

Nanotube Bundle

AbstractAtomistic simulations are used to better understand the behavior of bundles of single- walled carbon nanotubes that have been placed between two sliding diamond surfaces. A many-body reactive empirical potential for hydrocarbons that has been coupled to a Lennard-Jones potential is used to determine the energies and forces for all the atoms in the simulations. The results indicate that the degree of compression of the nanotube bundle between the nanotubes has a significant effect on the responses of the nanotubes to shear forces. However, no rolling of the nanotubes is predicted in contrast to previous studies of individual nanotubes moving on graphite.

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