Beyond the Embedded Atom Interatomic Potential

AbstractWe briefly discuss some of the advantages and limitations of using embedded atom interatomic potentials for simulating the static configuration and dynamics of lattice defects. In metals, the embedded atom potentials provide a physically more realistic approximation than simple pair interaction potentials without a significant increase in computer time needed for defect simulation studies. However, in some cases, n-body shear forces, i.e bond angle interatomic forces may be needed for fitting experimental results related to defect configuration. One such example is the elastic neutron scattering data from N interstitials in Nb [1]. Also, such bond angle forces must be included in a realistic model of atomic interactions in metals, expecially in highly anisotropic bee transition metals. Extending the concept of the embedded atom method, we propose a new form for the interatomic potential in metals which includes bond angle forces. General expressions for the elastic constants in bee and fee structures are deduced.

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Effects of Angular Dependent Terms in the Interatomic Potential on Defect Properties in TiAl

MRS Proceedings ◽

10.1557/proc-364-151 ◽

1994 ◽

Vol 364 ◽

Cited By ~ 3

Author(s):

Julia Panova ◽

Diana Farkas

Keyword(s):

Interatomic Potential ◽

Stacking Faults ◽

Core Structure ◽

Interatomic Potentials ◽

The Core ◽

Embedded Atom ◽

Dependent Term

AbstractInteratomic potentials of the Embedded Atom and Embedded Defect types were used to study the effect of the angular dependent term in the Embedded Defect potential on the properties of defects in TiAl. The defect properties were computed with interatomic potentials developed with and without angular dependent terms. It was found that the inclusion of the angular dependent terms tends to increase the energies of the APB’s and lower the energies of stacking faults. The effects of the angular term on the relaxation around vacancies and antisites in TiAl was also studied, as well as the core structure of several dislocations in this compound.

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Modeling of supersonic crowdion clusters in FCC lattice: Effect of the interatomic potential

Journal of Micromechanics and Molecular Physics ◽

10.1142/s2424913020500198 ◽

2021 ◽

pp. 2050019

Author(s):

Igor A. Shelepev ◽

Ayrat M. Bayazitov ◽

Elena A. Korznikova

Keyword(s):

Interatomic Potential ◽

High Energy ◽

Propagation Path ◽

Interatomic Potentials ◽

Energy Localization ◽

Many Body ◽

Embedded Atom ◽

Fcc Lattice ◽

The Many ◽

Body Potential

Among a wide variety of point defects, crowdions can be distinguished by their high energy of formation and relatively low migration barriers, which makes them an important agent of mass transfer in lattices subjected to severe plastic deformation, irradiation, etc. It was previously shown that complexes and clusters of crowdions are even more mobile than single interstitials, which opened new mechanisms for the transfer of energy and mass in materials under intense external impacts. One of the most popular and convenient methods for analyzing crowdions is molecular dynamics, where the results can strongly depend on the interatomic potential used in the study. In this work, we compare the characteristics of a crowdion in an fcc lattice obtained using two different interatomic potentials — the pairwise Morse potential and the many-body potential for Al developed by the embedded atom method. It was found that the use of the many-body potential significantly affects the dynamics of crowdion propagation, including the features of atomic collisions, the evolution of energy localization and the propagation path.

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Empirical Interatomic Potentials for L1O Tial and B2 Nial

MRS Proceedings ◽

10.1557/proc-213-125 ◽

1990 ◽

Vol 213 ◽

Cited By ~ 24

Author(s):

Satish I. Rao ◽

C. Woodward ◽

T.A. Parthasarathy

Keyword(s):

Interatomic Potential ◽

Dislocation Core ◽

Interatomic Potentials ◽

Electronic Effects ◽

Bulk Properties ◽

Embedded Atom ◽

Fitting Procedure ◽

Planar Fault ◽

Potential Methods ◽

Semi Empirical

ABSTRACTRecent studies have suggested a particular relationship between the degree of covalent bonding in TiAl and the mobility of dislocation[1,2]. Ultimately such electronic effects In ordered compounds must dictate the dislocation core structures and at the same time the dislocation mobility within a given compound. However, direct modelling of line defects Is beyond the capability of todays electronic structure techniques. Alternatively, significant steps toward extending our understanding of the flow behaviour of structural intermetallics may come through general application of empirical interatomic potential methods for calculating the structure and mobility of defects. Toward this end, we have constructed semi-empirical interatomic potentials within the embedded atom formalism for L1O and B2 type structures. These potentials have been determined by fitting to known bulk structural and elastic properties of TIAl and NiAl, using least squares procedures. Simple expressions that relate the parameters of the potentials to the bulk properties are used in the fitting procedure. Calculations of dislocation core structures and planar fault energies using these potentials are considered. The differences between the optimized bulk properties predicted from the potentials and the values for these properties are discussed in terms of non-spherical nature of the electron density distribution. Empirical methods which incorporate these effects into interatomic potentials are briefly discussed.

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Interatomic Potentials for Atomistic Simulations

MRS Bulletin ◽

10.1557/s0883769400046248 ◽

1996 ◽

Vol 21 (2) ◽

pp. 17-19 ◽

Cited By ~ 17

Author(s):

Arthur F. Voter

Keyword(s):

Atomistic Simulation ◽

Large Scale ◽

Materials Science ◽

Interatomic Potential ◽

Computer Time ◽

Atomistic Simulations ◽

Interatomic Potentials ◽

Materials Research ◽

Recent Developments ◽

Time Required

Atomistic simulations are playing an increasingly prominent role in materials science. From relatively conventional studies of point and planar defects to large-scale simulations of fracture and machining, atomistic simulations offer a microscopic view of the physics that cannot be obtained from experiment. Predictions resulting from this atomic-level understanding are proving increasingly accurate and useful. Consequently, the field of atomistic simulation is gaining ground as an indispensable partner in materials research, a trend that can only continue. Each year, computers gain roughly a factor of two in speed. With the same effort one can then simulate a system with twice as many atoms or integrate a molecular-dynamics trajectory for twice as long. Perhaps even more important, however, are the theoretical advances occurring in the description of the atomic interactions, the so-called “interatomic potential” function.The interatomic potential underpins any atomistic simulation. The accuracy of the potential dictates the quality of the simulation results, and its functional complexity determines the amount of computer time required. Recent developments that fit more physics into a compact potential form are increasing the accuracy available per simulation dollar.This issue of MRS Bulletin offers an introductory survey of interatomic potentials in use today, as well as the types of problems to which they can be applied. This is by no means a comprehensive review. It would be impractical here to attempt to present all the potentials that have been developed in recent years. Rather, this collection of articles focuses on a few important forms of potential spanning the major classes of materials bonding: covalent, metallic, and ionic.

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Embedded - Atom - Method Interatomic Potentials for BCC - Iron

MRS Proceedings ◽

10.1557/proc-291-567 ◽

1992 ◽

Vol 291 ◽

Cited By ~ 87

Author(s):

G. Simonelli ◽

R. Pasianot ◽

E.J. Savino

Keyword(s):

Point Defects ◽

Interatomic Potential ◽

Lattice Parameter ◽

Embedded Atom Method ◽

Interatomic Potentials ◽

Embedded Atom ◽

Bcc Iron ◽

Defect Energies ◽

Functional Fitting ◽

Formation Energies

ABSTRACTAn embedded-atom-method (EAM) interatomic potential [1] for bcc-iron is derived. It is fitted exactly to the lattice parameter, elastic constants, an approximation to the unrelaxed vacancy formation energy, and Rose's expression for the cohesive energy [2]. Formation energies and relaxation volumes of point defects are calculated. We find that the relative energies of the defect configurations depend on the functional fitting details of the potential considered, mainly its range: the experimental interstitial configuration of lowest energy can be reproduced by changing this parameter. This result is confirmed by calculating the same defect energies using other EAM potentials, based on the ones developed by Harrison et al. [3].

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Reliability of EAM potentials for FCC metals properties prediction

10.32469/10355/78126 ◽

2020 ◽

Author(s):

◽

Seyed Moein Rassoulinejad Mousavi

Keyword(s):

Interatomic Potential ◽

Elastic Stiffness ◽

Dynamics Simulation ◽

Interatomic Potentials ◽

Validity Of Results ◽

University Of Missouri ◽

Embedded Atom ◽

Different Temperatures ◽

Experimental Values ◽

The Right

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI--COLUMBIA AT REQUEST OF AUTHOR.] A perfectly transferable interatomic potential that works for different materials and systems of interest is lacking. This work considers the transferability of several existing interatomic potentials by evaluating their capability at various temperatures, to determine the range of accuracy of these potentials in atomistic simulations. A series of embedded-atom-method (EAM) based interatomic potentials has been examined for precious and popular metals in nanoscale studies. The potentials have been obtained from various credible and trusted repositories and were compared to tackle the lack of a comparison between several existing models. The interatomic potentials designed for the single elements, binary, trinary and higher order compounds were tested for each species using molecular dynamics simulation. Validity of results arising from each potential was investigated against experimental values at different temperatures from a temperature range around Debye temperature to melting point. The data covers accuracy of all studied potentials for prediction of the single crystals' elastic stiffness constants as well as the bulk, shear and Young's modulus of the polycrystalline specimens. As testing and benchmarking results for users is a necessity before running a new simulation, results of this work increase their assurance and lead them to the right model by a way to easily look up data. Referring to this work also prevents any inaccurate prediction by an atomistic simulation due to use of an inappropriate interatomic potential.

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Quantifying Parameter Sensitivity and Uncertainty for Interatomic Potential Design: Application to Saturated Hydrocarbons

ASCE-ASME J Risk and Uncert in Engrg Sys Part B Mech Engrg ◽

10.1115/1.4037455 ◽

2017 ◽

Vol 4 (1) ◽

Cited By ~ 2

Author(s):

Mark A. Tschopp ◽

B. Chris Rinderspacher ◽

Sasan Nouranian ◽

Mike I. Baskes ◽

Steven R. Gwaltney ◽

...

Keyword(s):

Interatomic Potential ◽

Fractional Factorial ◽

Interatomic Potentials ◽

Latin Hypercube Design ◽

Training Set ◽

Saturated Hydrocarbons ◽

Bond Angles ◽

Embedded Atom ◽

The Relationship ◽

Potential Parameters

The research objective herein is to understand the relationships between the interatomic potential parameters and properties used in the training and validation of potentials, specifically using a recently developed modified embedded-atom method (MEAM) potential for saturated hydrocarbons (C–H system). This potential was parameterized to a training set that included bond distances, bond angles, and atomization energies at 0 K of a series of alkane structures from methane to n-octane. In this work, the parameters of the MEAM potential were explored through a fractional factorial design and a Latin hypercube design to better understand how individual MEAM parameters affected several properties of molecules (energy, bond distances, bond angles, and dihedral angles) and also to quantify the relationship/correlation between various molecules in terms of these properties. The generalized methodology presented shows quantitative approaches that can be used in selecting the appropriate parameters for the interatomic potential, selecting the bounds for these parameters (for constrained optimization), selecting the responses for the training set, selecting the weights for various responses in the objective function, and setting up the single/multi-objective optimization process itself. The significance of the approach applied in this study is not only the application to the C–H system but that the broader framework can also be easily applied to any number of systems to understand the significance of parameters, their relationships to properties, and the subsequent steps for designing interatomic potentials under uncertainty.

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Lattice Trapping of Cracks in Fe Using an Interatomic Potential Derived from Experimental Data and Ab Initio Calculations

MRS Proceedings ◽

10.1557/proc-653-z6.4 ◽

2000 ◽

Vol 653 ◽

Author(s):

D. Farkas ◽

M. J. Mehl ◽

D. A. Papaconstantopoulos

Keyword(s):

Experimental Data ◽

Interatomic Potential ◽

Interatomic Potentials ◽

Coordination Numbers ◽

Embedded Atom ◽

Recent Approach ◽

Basic Equilibrium ◽

Stability Of Structures ◽

Formation Energies ◽

Trapping Effects

AbstractA recent approach which combines first-principles and experimental data to produce highly accurate and reliable interatomic potentials is tested for the case of bcc and fcc Fe. The Embedded-Atom-like potential accurately reproduces the basic equilibrium properties of bcc Fe, including elastic constants, phonon properties, and vacancy formation energies, as well as the correct relative stability of structures with coordination numbers ranging from 12 to 4. This potential was used in a simulation study of lattice trapping effects during the cleavage fracture of bcc Fe. A strong directional anisotropy for crack propagation was observed due to lattice trapping effects. The strongest trapping effects were observed for cleavage along the {110} planes and it was found that lattice trapping strongly favors cleavage along the {100} planes.

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