MEAM interatomic potentials of Ni, Re, and Ni-Re alloys for atomistic fracture simulations

2021 ◽  
Author(s):  
Masud Alam ◽  
L Lymperakis ◽  
Sebastien Groh ◽  
Joerg Neugebauer
Keyword(s):  
Density Functional ◽  
Large Scale ◽  
Nearest Neighbor ◽  
Dominant Role ◽  
Critical Stress Intensity Factor ◽  
Embedded Atom Method ◽  
Interatomic Potentials ◽  
Functional Theory ◽  
Embedded Atom ◽  
Large Scale Simulations

Abstract Second nearest neighbor modified embedded atom method (2NN-MEAM) interatomic potentials are developed for the Ni, Re, and Ni-Re binaries. To construct the potentials, density functional theory (DFT) calculations have been employed to calculate fundamental physical properties that play a dominant role in fracture. The potentials are validated to accurately reproduce material properties that correlate with material’s fracture behavior. The thus constructed potentials were applied to perform large scale simulations of mode I fracture in Ni and Ni-Re binaries with low Re content. Substitutional Re did not alter the ductile nature of crack propagation, though it resulted in a monotonous increase of the critical stress intensity factor with Re content.

Classical Interatomic Potential for Nb-Alumina Interfaces

2000 ◽  
Vol 654 ◽  
Author(s):  
K. Albe ◽  
R. Benedek ◽  
D. N. Seidman ◽  
R.S. Averback
Keyword(s):  
Density Functional ◽  
Large Scale ◽  
Interatomic Potential ◽  
Local Density ◽  
Embedded Atom Method ◽  
Metal Interface ◽  
Functional Theory ◽  
Embedded Atom ◽  
Local Density Functional Theory ◽  
Modified Embedded Atom Method

AbstractA modified-embedded-atom-method (MEAM) potential is derived for the ternary system Al-O-Nb in order to simulate the model oxide-metal interface sapphire-niobium. In the present work, MEAM parameters for Al and O given by Baskes were adopted, and the parameters for Nb are adjusted to match experimental data for pure Nb and calculated properties for Nb oxides and aluminides. The properties for niobium oxides and aluminides were obtained from local- density-functional-theory (LDFT) calculations. The resultant potential was tested in simulations for the Nb(111)/α -alumina(0001) interface. MEAM predictions of the work of separation and the interlayer relaxations for two interface terminations are in excellent agreement with LDFT calculations. The MEAM potential therefore appears suitable for large-scale computer simulation of oxide-metal interface properties.

Semi-Empirical Potential Methods for Atomistic Simulations of Metals and Their Construction Procedures

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
Seong-Gon Kim ◽  
M. F. Horstemeyer ◽  
M. I. Baskes ◽  
Masoud Rais-Rohani ◽  
Sungho Kim ◽  
...  
Keyword(s):  
Material Properties ◽  
Density Functional ◽  
Embedded Atom Method ◽  
Functional Theory ◽  
Empirical Potential ◽  
Embedded Atom ◽  
Target Values ◽  
Potential Methods ◽  
Semi Empirical ◽  
Cohesive Energies

General theory of semi-empirical potential methods including embedded-atom method and modified-embedded-atom method (MEAM) is reviewed. The procedures to construct these potentials are also reviewed. A multi-objective optimization (MOO) procedure has been developed to construct MEAM potentials with minimal manual fitting. This procedure has been applied successfully to develop a new MEAM potential for magnesium. The MOO procedure is designed to optimally reproduce multiple target values that consist of important material properties obtained from experiments and first-principle calculations based on density-functional theory. The optimized target quantities include elastic constants, cohesive energies, surface energies, vacancy-formation energies, and the forces on atoms in a variety of structures. The accuracy of the present potential is assessed by computing several material properties of Mg including their thermal properties. We found that the new MEAM potential shows a significant improvement over previously published potentials, especially for the atomic forces and melting temperature calculations.

Development of a 2NN-MEAM potential for boron

2021 ◽  
pp. 2050008
Author(s):  
Siamak Attarian ◽  
Shaoping Xiao
Keyword(s):  
Potential Function ◽  
Density Functional ◽  
Nearest Neighbor ◽  
Experimental Studies ◽  
Md Simulations ◽  
Mechanical And Thermal Properties ◽  
Functional Theory ◽  
Embedded Atom ◽  
The Density Functional Theory ◽  
Comprehensive Comparison

In this paper, we present the first work in developing a second nearest-neighbor modified embedded atom method (2NN-MEAM) potential function that can be used to model interatomic interactions in both [Formula: see text] boron and [Formula: see text] boron polymorphs. To fit the potential parameters by optimization, some physical properties and elastic constants of boron, calculated from the density functional theory, are adopted as the targets in the objective function. The developed potential is utilized in molecular dynamics (MD) simulations to calculate the physical, mechanical, and thermal properties of [Formula: see text] boron and [Formula: see text] boron. A comprehensive comparison is conducted between the MD simulations and various experimental studies if available to validate the developed potential function. It is concluded that the developed 2NN-MEAM potential can be practically employed in MD modeling and simulation of boron. This work will also enhance the future development of binary potentials for boron compounds to study boron-based composites via MD.

First-Principles Studies of Structural Domain Walls

Domain Walls ◽  
2020 ◽  
pp. 36-75
Author(s):  
J. Íñiguez
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Large Scale ◽  
Domain Walls ◽  
Perovskite Oxides ◽  
Added Value ◽  
Structural Domain ◽  
Simulation Methods ◽  
Functional Theory ◽  
Large Scale Simulations

This chapter discusses representative first-principles studies of structural domain walls in ferroics, focusing on the compounds that have received most attention by the simulations community so far: perovskite oxides. It describes in some detail a reduced number of case studies that come handy to illustrate different effects and to highlight the added value of the first-principles investigations. As regards the simulation methods, the chapter focuses on applications of density functional theory (DFT), typically employing an approximation for an effective treatment of ionic cores. A discussion on the application to domain-wall problems of first-principles-based methods for large-scale simulations of ferroelectrics and ferroelastics is also included. Finally, this chapter briefly on the opportunities and challenges for first-principles research in this field.

Negative Cauchy Pressure within the Tight-Binding Approximation

1997 ◽  
Vol 491 ◽  
Author(s):  
D. Nguyen-Maxh ◽  
D. G. Pettifor ◽  
S. Znam ◽  
V. Vitek
Keyword(s):  
Density Functional ◽  
Functional Form ◽  
Tight Binding ◽  
Embedded Atom Method ◽  
Tight Binding Approximation ◽  
Functional Theory ◽  
Cubic Metals ◽  
Embedded Atom ◽  
Cauchy Pressure ◽  
Environment Dependence

ABSTRACTIt is well-known that the Embedded Atom Method (EAM) predicts positive Cauchy pressures for cubic metals if physically-motivated embedding functions are used. Supris-ingly, even if the angular character of the covalent bonding is included within an orthorgonal or non-orthorgonal Tight-Binding (TB) description, the Cauchy pressure for most elemental and binary metallic systems remains positive. We describe the results of a detailed breakdown of the different contributions to the Cauchy pressure within the Harris-Foulkes approximation (HFA) to density functional theory. We show that negative values of the Cauchy pressure for both elemental transition metals such as Ir and binary intermetallics such as Ti3Al, TiAl and TiAl3 are well reproduced by the HFA. We argue that the negative Cauchy pressure (NCP) arises namely from the environment dependence of the local TB orbitals which leads to both environment-dependent bonding integrals and overlap repulsion. We discuss a particular functional form for overlap repulsion which leads to NCP and compare it with different fitting schemes proposed recently in TB theory.

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