Molecular Dynamics Study of (001) and (111) Thin Fcc Films

1990 ◽  
Vol 187 ◽  
Author(s):  
F.H. Streitz ◽  
K. Sieradzki ◽  
R. C. Cammarata
Keyword(s):  
Molecular Dynamics ◽  
Interatomic Potential ◽  
Analytic Form ◽  
Jones Potential ◽  
Lennard Jones ◽  
Embedded Atom ◽  
Atomic Interactions ◽  
Low Levels ◽  
Dynamics Simulations ◽  
Thermodynamic Instability

AbstractWe report on the results of molecular dynamics simulations of thin unsupported fcc films ranging in thickness from 20 layers to a monolayer. The films were oriented with either (001) or (111) free surface normals. The atomic interactions were modelled using a standard Lennard-Jones potential and a short range analytic form of the embedded atom potential. The elastic moduli of the films were determined by measuring their response to very low levels of applied stress.We find that the embedded atom and Lennard-Jones results are in relative agreement for (001) films and qualitative disagreement for (111) oriented films. We relate these differences to the nature of the interatomic potential and the thermodynamic instability of the (001) surface.

Molecular Dynamics Prediction of the Influence of Composition on Thermotransport in Ni-Al Melts

2017 ◽  
Vol 12 ◽  
pp. 93-110 ◽  
Author(s):  
Tanvir Ahmed ◽  
Elena V. Levchenko ◽  
Alexander V. Evteev ◽  
Zi Kui Liu ◽  
William Yi Wang ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Interatomic Potential ◽  
Diffusion In Solids ◽  
Recent Experimental Study ◽  
Heat Of Transport ◽  
Embedded Atom ◽  
Rich Liquid ◽  
Predicted Values ◽  
Dynamics Simulations ◽  
Embedded Atom Method Potential

The influence of composition on thermotransport (coupling between mass and heat transport) in Ni-Al melts is investigated by making use of equilibrium molecular dynamics simulations in conjunction with the Green-Kubo formalism. To describe interatomic interactions in Ni-Al melt models, we employ the embedded-atom method potential developed in [G.P. Purja Pun, Y. Mishin, Phil. Mag., 2009, 89, 3245]. It is demonstrated that the employed interatomic potential gives good agreement with the recent experimental study [E. Sondermann, F. Kargl, A. Meyer, Presented at the 12th International Conference on Diffusion in Solids and Liquids (DSL-2016), 26-30 June 2016, Split, Croatia] regarding the direction of thermotransport in Al-rich liquid Ni-Al alloys. Moreover, the predicted values of the reduced heat of transport (the quantity which explicitly characterizes both the magnitude and direction of thermotransport) in Ni-Al melts, reveal fairly weak composition dependence while being practically independent of temperature at all. Accordingly, in the presence of a temperature gradient, our simulation results for the models of liquid Ni25Al75, Ni50Al50 and Ni75Al25 alloys predict consistently Ni and Al to migrate to the cold and hot ends, respectively. Meanwhile, the highest value, about eV, of the reduced heat of transport is observed for Ni50Al50 alloy model and it slightly decreases towards Al-rich and Ni-rich compositions.

Direct Molecular Dynamics Simulations of Diffusion Mechanisms in NiAl

2000 ◽  
Vol 646 ◽  
Author(s):  
D. Farkas ◽  
B. Soulé de Bas
Keyword(s):  
Molecular Dynamics ◽  
High Temperature ◽  
Molecular Dynamics Simulations ◽  
Sequential Analysis ◽  
Nearest Neighbor ◽  
Interatomic Potential ◽  
Embedded Atom ◽  
Diffusion Mechanisms ◽  
Dynamics Simulations ◽  
Potential Diffusion

ABSTRACTMolecular dynamics simulations of the diffusion process in ordered B2 NiAl at high temperature were performed using an embedded atom interatomic potential. Diffusion occurs through a variety of cyclic mechanisms that accomplish the motion of the vacancy through nearest neighbor jumps restoring order to the alloy at the end of the cycle. The traditionally postulated 6-jump cycle is only one of the various cycles observed and some of these are quite complex. A detailed sequential analysis of the observed 6-jump cycles was performed and the results are analyzed in terms of the activation energies for individual jumps calculated using molecular statics simulations.

Structure of a Dissociated Edge Dislocation in Copper

1999 ◽  
Vol 578 ◽  
Author(s):  
L. F. Perondi ◽  
P. Szelestey ◽  
K. Kaski
Keyword(s):  
Molecular Dynamics ◽  
Boundary Conditions ◽  
Edge Dislocation ◽  
Equilibrium Distance ◽  
Embedded Atom ◽  
Equilibrium Size ◽  
Atomic Interactions ◽  
Simulated System ◽  
Dynamics Simulations ◽  
Eam Potential

AbstractThe structure of a dissociated edge dislocation in copper is investigated. Attention is given to the structure of the Shockley partials and the equilibrium size of the fault ribbon. The studies are carried out through Molecular Dynamics simulations. The atomic interactions have been modelled through an Embedded Atom Model (EAM) potential. the implementation of which has been specially designed for this study. Our main results show that the equilibrium distance between partials is very sensitive to the type of boundary conditions imposed on the simulated system.

Simulation of Recrystallization Using Molecular Dynamics; Effects of the Interatomic Potential

2007 ◽  
Vol 558-559 ◽  
pp. 1081-1086 ◽  
Author(s):  
Rasmus B. Godiksen ◽  
Zachary T. Trautt ◽  
Moneesh Upmanyu ◽  
Søren Schmidt ◽  
Dorte Juul Jensen
Keyword(s):  
Molecular Dynamics ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Interatomic Potential ◽  
Driving Forces ◽  
Boundary Migration ◽  
Grain Boundary Migration ◽  
High Angle ◽  
Embedded Atom ◽  
Atomic Interactions

Recrystallization is governed by the migration of high angle grain boundaries traveling through a deformed material driven by the excess energy located primarily in dislocation structures. A method for investigating the interaction between a migrating grain boundary and dislocation boundaries using molecular dynamics (MD) was recently developed. During simulations migrating high angle grain boundaries interact with dislocation boundaries, and individual dislocations from the dislocation boundaries are absorbed into the grain boundaries. Results obtained previously, using a simple Lennard-Jones (LJ) potential, showed surprisingly irregular grain boundary migration compared to simulations of grain boundary migration applying other types of driving forces. Inhomogeneous boundary-dislocation interactions were also observed in which the grain boundaries locally acquired significant cusps during dislocation absorption events. The study presented here makes comparisons between simulations performed using a LJ- and an embedded atom method (EAM) aluminum potential. The results show similarities which indicate that it is the crystallographic features rather than the atomic interactions that determine the details of the migration process.

scholarly journals Data driven inference for the repulsive exponent of the Lennard-Jones potential in molecular dynamics simulations

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Lina Kulakova ◽  
Georgios Arampatzis ◽  
Panagiotis Angelikopoulos ◽  
Panagiotis Hadjidoukas ◽  
Costas Papadimitriou ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Data Driven ◽  
Lennard Jones Potential ◽  
Jones Potential ◽  
Lennard Jones ◽  
Dynamics Simulations

Molecular Dynamics of Crack Propagation in Nickel and Nickel-Aluminum Bimetal Interface

2010 ◽  
Author(s):  
Yojna Purohit ◽  
Ram Mohan
Keyword(s):  
Molecular Dynamics ◽  
Crack Propagation ◽  
Interatomic Potential ◽  
Process Zone ◽  
Crack Tip ◽  
Nickel Aluminum ◽  
Embedded Atom ◽  
Propagation Behavior ◽  
Dynamics Simulations ◽  
Rayleigh Wave Speed

Molecular dynamics simulations were used to study crack propagation in a Nickel single crystal and a Nickel-Aluminum bimetal interface. The embedded atom method interatomic potential was used to investigate the behavior of (001) [100] crack system under mode I loading in the two systems. The propagation mechanisms and fracture behavior and properties of a propagating crack in Ni were compared with propagation, behavior and properties of a surface crack in Ni-Al that initiates and propagates from Ni towards the Ni-Al bimetal interface. Our results for Ni show an initial brittle crack propagation followed by a roughening of the crack surfaces at one-third of the Rayleigh wave speed and are in agreement with previous investigations. In Ni-Al the crack surfaces initially grow brittle. However, two regimes of crack propagation velocities were observed in this case with crack getting decelerated as it nears the interface. Further dynamic analysis of the crack propagation indicated a cease in the crack propagation in Ni due to a brittle to ductile transition. In Ni-Al bimetal interface system, as the crack approaches the interface, a process zone representing local disorder at the crack tip was observed to start growing and interacting with interfacial defects that eventually results in a blunting of the crack tip.

scholarly journals Modeling Interactions between Graphene and Heterogeneous Molecules

Computation ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 107
Author(s):  
Kyle Stevens ◽  
Thien Tran-Duc ◽  
Ngamta Thamwattana ◽  
James M. Hill
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Continuous Model ◽  
Atomic Density ◽  
Lennard Jones Potential ◽  
Jones Potential ◽  
New Model ◽  
Lennard Jones ◽  
Continuous Surface ◽  
Dynamics Simulations

The Lennard–Jones potential and a continuum approach can be used to successfully model interactions between various regular shaped molecules and nanostructures. For single atomic species molecules, the interaction can be approximated by assuming a uniform distribution of atoms over surfaces or volumes, which gives rise to a constant atomic density either over or throughout the molecule. However, for heterogeneous molecules, which comprise more than one type of atoms, the situation is more complicated. Thus far, two extended modeling approaches have been considered for heterogeneous molecules, namely a multi-surface semi-continuous model and a fully continuous model with average smearing of atomic contribution. In this paper, we propose yet another modeling approach using a single continuous surface, but replacing the atomic density and attractive and repulsive constants in the Lennard–Jones potential with functions, which depend on the heterogeneity across the molecules, and the new model is applied to study the adsorption of coronene onto a graphene sheet. Comparison of results is made between the new model and two other existing approaches as well as molecular dynamics simulations performed using the LAMMPS molecular dynamics simulator. We find that the new approach is superior to the other continuum models and provides excellent agreement with molecular dynamics simulations.

Characterization of Interatomic Potentials by a Calculation of Defect Energy

1997 ◽  
Vol 491 ◽  
Author(s):  
Y. Kogure ◽  
M. Doyama
Keyword(s):  
Molecular Dynamics ◽  
Noble Metals ◽  
Dynamics Simulation ◽  
Interatomic Potentials ◽  
Third Order ◽  
Jones Potential ◽  
Embedded Atom ◽  
Third Order Elastic Constants ◽  
Dynamics Simulations

ABSTRACTPotential functions used in molecular dynamics simulations for metals are characterized through a calculation of the third-order elastic constants, the Gruneisen parameters, and the molecular dynamics simulation of point defects. The Lennard-Jones potential and the embedded atom method potentials for noble metals (Cu, Ag, Au) are characterized by using a common program code.

Molecular Dynamics Study of Size Dependence of Combustion of Aluminum Nanoparticles

2012 ◽  
Vol 1405 ◽  
Author(s):  
Ying Li ◽  
Richard Clark ◽  
Aiichiro Nakano ◽  
Rajiv K. Kalia ◽  
Priya Vashishta
Keyword(s):  
Molecular Dynamics ◽  
Size Dependence ◽  
Interatomic Potential ◽  
Onset Time ◽  
Aluminum Nanoparticles ◽  
Change Rate ◽  
Reactive Molecular Dynamics ◽  
Embedded Atom ◽  
Temperature Change Rate ◽  
Dynamics Simulations

ABSTRACTOxidation dynamics of three different sizes (26, 36 and 46 nm) of single aluminum nanoparticle (ANP) in oxygen environment are studied using multimillion-atom reactive molecular dynamics simulations. In the simulation, each aluminum nanoparticle is coated with an amorphous alumina shell of the same thickness (3 nm), and is ignited by heating the nanoparticle to 1100 K. The metallic aluminum and ceramic alumina are modeled by the Voter- Chen embedded atom model and the interatomic potential by Vashishta et al., respectively. Energy release rate and atomistic-level details of combustion of these single aluminum nanoparticles are investigated, along with the effect of nanoparticle size. The onset temperature of shell Al ejection is found to be independent of the ANP size, whereas the onset time of ejection and the time delay to the highest temperature change rate dT/dt depend on the size.

Molecular Dynamics Prediction of the Thermal Resistance of Solid-Solid Interfaces in Superlattices

2006 ◽  
Author(s):  
A. J. H. McGaughey ◽  
J. Li
Keyword(s):  
Molecular Dynamics ◽  
Thermal Resistance ◽  
Ballistic Transport ◽  
System Size ◽  
Phonon Transport ◽  
Kubo Formula ◽  
Jones Potential ◽  
Lennard Jones ◽  
Interface Thermal Resistance ◽  
Dynamics Simulations

Molecular dynamics simulations are used to predict the thermal resistance of solid-solid interfaces in crystalline superlattices using a new Green-Kubo formula. The materials on both sides of the interfaces studied are modeled with the Lennard-Jones potential and are only differentiated by their masses. To obtain the interface thermal resistance, a correlation length in the bulk materials is first predicted, which approaches a system-size independent value for larger systems. The interface thermal resistance is found to initially increase as the layer length is increased, and then to decrease as the phonon transport shifts from a regime dominated by ballistic transport to one dominated by diffusive transport.

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