Strengthening Behavior and Tension–Compression Strength–Asymmetry in Nanocrystalline Metal–Ceramic Composites

2012 ◽  
Vol 134 (4) ◽  
Author(s):  
A. M. Dongare ◽  
B. LaMattina ◽  
A. M. Rajendran
Keyword(s):  
Molecular Dynamics ◽  
Volume Fraction ◽  
Md Simulations ◽  
Ceramic Composites ◽  
Embedded Atom Method ◽  
Nanocrystalline Metal ◽  
Rich Region ◽  
Embedded Atom ◽  
Metal Ceramic ◽  
Strength Asymmetry

Metal–ceramic composites are an emerging class of materials for use in the next-generation high technology applications due to their ability to sustain plastic deformation and resist failure in extreme mechanical environments. Large scale molecular dynamics simulations are used to investigate the performance of nanocrystalline metal–matrix composites (MMCs) formed by the reinforcement of the nanocrystalline Al matrix with a random distribution of nanoscale ceramic particles. The interatomic interactions are defined by the newly developed angular-dependent embedded atom method (A-EAM) by combining the embedded atom method (EAM) potential for Al with the Stillinger–Weber (SW) potential for Si in one functional form. The molecular dynamics (MD) simulations are aimed to investigate the strengthening behavior and the tension–compression strength asymmetry of these composites as a function of volume fraction of the reinforcing Si phase. MD simulations suggest that the strength of the nanocomposite increases linearly with an increase in the volume fraction of Si in the Al-rich region, whereas the increase is very sharp in the Si-rich region. The higher strength of the nanocomposite is attributed to the reduced sliding/rotation between the Al/Si and the Si/Si grains as compared to the pure nanocrystalline metal.

Molecular dynamics simulations of grain boundary diffusion in Al using embedded atom method potentials

1995 ◽  
Vol 10 (7) ◽  
pp. 1589-1592 ◽  
Author(s):  
Chun-Li Liu ◽  
S.J. Plimpton
Keyword(s):  
Molecular Dynamics ◽  
Grain Boundary ◽  
Boundary Diffusion ◽  
Md Simulations ◽  
Embedded Atom Method ◽  
Melting Temperatures ◽  
Embedded Atom ◽  
Pair Potentials ◽  
Dynamics Simulations ◽  
First Time

Molecular dynamics (MD) simulations of diffusion in a Σ5(310) [001] Al tilt grain boundary were performed using for the first time three different potentials based on the embedded atom method (EAM). The EAM potentials that produce more accurate melting temperatures also yield activation energies in better agreement with experimental data. Compared to pair potentials, the EAM potentials also give more accurate results.

Molecular Dynamics Study of Mass Transport Properties of Liquid Cu-Ag Alloys

2016 ◽  
Vol 9 ◽  
pp. 58-72 ◽  
Author(s):  
U. Sarder ◽  
Alexander V. Evteev ◽  
Elena V. Levchenko ◽  
A. Kromik ◽  
I.V. Belova ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Mass Transport ◽  
Transport Properties ◽  
Diffusion Coefficients ◽  
Md Simulations ◽  
Embedded Atom Method ◽  
Self Diffusion ◽  
Phenomenological Coefficient ◽  
Embedded Atom ◽  
Kinetics Of

In this study, mass transport properties of liquid Cu-Ag alloys are investigated over wide temperature and composition ranges. The calculations are performed within the framework of the Green-Kubo (GK) formalism by using equilibrium molecular dynamics (MD) simulations along with one of the most reliable embedded-atom method potentials for this system developed by [P. Williams et al.: Modell. Simul. Mater. Sci. Eng. vol. 14 (2006), p. 817]. The approach employed allows for evaluation of the components’ self-diffusion coefficients as well as the phenomenological coefficient for mass transport Lcc. The results obtained in this study can be used to predict the kinetics of solidification of real liquid Cu-Ag alloys.

Parallel Molecular Dynamics With the Embedded Atom Method

1992 ◽  
Vol 291 ◽  
Author(s):  
Steven J. Plimpton ◽  
Bruce A. Hendrickson
Keyword(s):  
Molecular Dynamics ◽  
Md Simulations ◽  
Parallel Computers ◽  
Embedded Atom Method ◽  
Geometric Information ◽  
Parallel Methods ◽  
Embedded Atom ◽  
Multiple Data ◽  
Parallel Molecular Dynamics ◽  
Force Decomposition

ABSTRACTParallel computing offers new capabilities for using molecular dynamics (MD) to simulate larger numbers of atoms and longer time scales. In this paper we discuss two methods we have used to implement the embedded atom method (EAM) formalism for molecular dynamics on multiple-instruction/multiple-data (MIMD) parallel computers. The first method (atom-decomposition) is simple and suitable for small numbers of atoms. The second method (force-decomposition) is new and is particularly appropriate for the EAM because all the computations are between pairs of atoms. Both methods have the advantage of not requiring any geometric information about the physical domain being simulated. We present timing results for the two parallel methods on a benchmark EAM problem and briefly indicate how the methods can be used in other kinds of materials MD simulations.

Predicting XAFS scattering path cumulants and XAFS spectra for metals (Cu, Ni, Fe, Ti, Au) using molecular dynamics simulations

2013 ◽  
Vol 20 (4) ◽  
pp. 555-566 ◽  
Author(s):  
M. A. Karolewski ◽  
R. G. Cavell ◽  
R. A. Gordon ◽  
C. J. Glover ◽  
M. Cheah ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Md Simulations ◽  
Embedded Atom Method ◽  
Interatomic Potentials ◽  
Embedded Atom ◽  
Scaling Parameters ◽  
Order Of Magnitude ◽  
Experimental Errors ◽  
Dynamics Simulations ◽  
X Ray Absorption

The ability of molecular dynamics (MD) simulations to support the analysis of X-ray absorption fine-structure (XAFS) data for metals is evaluated. The low-order cumulants (ΔR, σ2,C3) for XAFS scattering paths are calculated for the metals Cu, Ni, Fe, Ti and Au at 300 K using 28 interatomic potentials of the embedded-atom method type. The MD cumulant predictions were evaluated within a cumulant expansion XAFS fitting model, using global (path-independent) scaling factors. Direct simulations of the corresponding XAFS spectra, χ(R), are also performed using MD configurational data in combination with theFEFFab initiocode. The cumulant scaling parameters compensate for differences between the real and effective scattering path distributions, and for any errors that might exist in the MD predictions and in the experimental data. The fitted value of ΔRis susceptible to experimental errors and inadvertent lattice thermal expansion in the simulation crystallites. The unadjusted predictions of σ2vary in accuracy, but do not show a consistent bias for any metal except Au, for which all potentials overestimate σ2. The unadjustedC3predictions produced by different potentials display only order-of-magnitude consistency. The accuracy of direct simulations of χ(R) for a given metal varies among the different potentials. For each of the metals Cu, Ni, Fe and Ti, one or more of the tested potentials was found to provide a reasonable simulation of χ(R). However, none of the potentials tested for Au was sufficiently accurate for this purpose.

Molecular Dynamics Simulations Based on Plastic Crystal Model with Introducing United Atom Scheme Demonstrated for Zr2Ni Metallic Glass

2012 ◽  
Vol 706-709 ◽  
pp. 1337-1342
Author(s):  
Akira Takeuchi ◽  
Akihisa Inoue
Keyword(s):  
Molecular Dynamics ◽  
Md Simulations ◽  
Simulation Method ◽  
Embedded Atom Method ◽  
Plastic Crystal ◽  
Embedded Atom ◽  
Ni Alloy ◽  
Crystal Model ◽  
Dynamics Simulations ◽  
Embedded Atom Method Potential

Molecular dynamics (MD) simulations were performed for a Zr2Ni alloy by referring to crystallographic features of a metastable Zr2Ni phase. Simulation method was identical to our previous studies named plastic crystal model (PCM), which includes crystallographic operations for an intermetallic compound in terms of the random rotations of hypothetical clusters around their center of gravity and subsequent annealing at a low temperature. On the basis of MD-PCM, the present study considers an additional refinement named united atom scheme (UAS) on the motions of atoms in the hypothetical clusters. In MD-PCM-UAS, Dreiding potential was assigned for atomic bonds in a cluster whereas Generalized Embedded Atom Method potential for the other atomic pairs. The simulation results by MD-PCM-UAS yield a liquid-like structure. However, annealing did not cause subsequent structural relaxation, which differs from the results by MD-PCM and conventional MD simulations. Further simulations based on MD-PCM-UAS were performed for a nanostructure comprising clusters and glue atoms, leading to the best fit with the experimental data.

How reliable is the ReaxFF potential for describing the structure of alkanethiols on gold? A molecular dynamics study

2014 ◽  
Vol 05 (supp01) ◽  
pp. 1441011 ◽  
Author(s):  
Velachi Vasumathi ◽  
José Luis Cagide Fajin ◽  
Maria Natália Dias Soeiro Cordeiro
Keyword(s):  
Molecular Dynamics ◽  
First Principles ◽  
Morse Potential ◽  
Md Simulations ◽  
Accurate Description ◽  
Self Assembled Monolayers ◽  
Embedded Atom Method ◽  
Embedded Atom ◽  
Novel Structure ◽  
Assembled Monolayers

The structures of self-assembled monolayers (SAMs) of short (methyl) and long (hexyl) chain alkyl thiols on the clean gold(111) surface were modeled using for the Au – S interactions either the reactive ReaxFF potential or the well-known nonreactive Morse potential, while for the Au – Au interactions either the ReaxFF potential or an embedded-atom method (EAM). Analysis of the molecular dynamics (MD) trajectories of possible SAM structures suggests that disordering of interfacial Au atoms is definitely driven by the gold–sulphur interactions. Our MD results reveal a novel structure where two methanethiol molecules are bound to a gold adatom that has been lifted from the surface at 300 K, and the same kind of RS– Au –SR motif was also observed for hexanethiol at 600 K but not at 300 K. What is more, the above motif is only observed for the reactive ReaxFF potential. Moreover, these results are in clear agreement with recent experiments and more costly first principles-based MD simulations. These findings strongly support the use of reactive potentials such as ReaxFF for gathering an accurate description of Au – S interactions in inexpensive classical MD simulations.

scholarly journals Modelling of Void Collapse with Molecular Dynamics in Pure Sn

Proceedings ◽  
2020 ◽  
Vol 56 (1) ◽  
pp. 29
Author(s):  
Georg Siroky ◽  
Elke Kraker ◽  
Dietmar Kieslinger ◽  
Lorenz Romaner ◽  
Ernst Kozeschnik ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Md Simulations ◽  
Embedded Atom Method ◽  
Liquid Viscosity ◽  
Spherical Void ◽  
Embedded Atom ◽  
Two Temperatures ◽  
Modified Embedded Atom Method ◽  
Pure Sn ◽  
Good Agreement

This work simulates the collapse of a spherical void in pure Sn during melting using molecular dynamics (MD). Simulations were performed for two temperatures with a modified embedded atom method (MEAM) potential, which was reported to be in good agreement with respect to melting point and elastic constants. Solutions of the Rayleigh–Plesset (RP) equation are used for comparison under the assumption of macroscopic surface tension and liquid viscosity. Despite a qualitative correlation, longer collapse times were observed in MD simulations, which arose from partial solid structures and the incubation time for melting.

Graphene-Based Resonant Sensors for Detection of Ultra-Fine Nanoparticles: Molecular Dynamics and Nonlocal Elasticity Investigations

NANO ◽  
2015 ◽  
Vol 10 (02) ◽  
pp. 1550024 ◽  
Author(s):  
S. Kamal Jalali ◽  
M. Hassan Naei ◽  
Nicola Maria Pugno
Keyword(s):  
Molecular Dynamics ◽  
Nonlocal Elasticity ◽  
Md Simulations ◽  
Small Scale ◽  
Frequency Shifts ◽  
Resonant Sensors ◽  
Embedded Atom ◽  
Metal Metal ◽  
Spring System ◽  
Mass Spring

Application of single layered graphene sheets (SLGSs) as resonant sensors in detection of ultra-fine nanoparticles (NPs) is investigated via molecular dynamics (MD) and nonlocal elasticity approaches. To take into consideration the effect of geometric nonlinearity, nonlocality and atomic interactions between SLGSs and NPs, a nonlinear nonlocal plate model carrying an attached mass-spring system is introduced and a combination of pseudo-spectral (PS) and integral quadrature (IQ) methods is proposed to numerically determine the frequency shifts caused by the attached metal NPs. In MD simulations, interactions between carbon–carbon, metal–metal and metal–carbon atoms are described by adaptive intermolecular reactive empirical bond order (AIREBO) potential, embedded atom method (EAM), and Lennard–Jones (L–J) potential, respectively. Nonlocal small-scale parameter is calibrated by matching frequency shifts obtained by nonlocal and MD simulation approaches with same vibration amplitude. The influence of nonlinearity, nonlocality and distribution of attached NPs on frequency shifts and sensitivity of the SLGS sensors are discussed in detail.

Molecular Dynamics Simulation of Sputtering with Mmany-Body Interactions

1988 ◽  
Vol 100 ◽  
Author(s):  
Davy Y. Lo ◽  
Tom A. Tombrello ◽  
Mark H. Shapiro ◽  
Don E. Harrison
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Single Crystal ◽  
Low Energy ◽  
Dynamics Simulation ◽  
Embedded Atom Method ◽  
Many Body ◽  
Embedded Atom ◽  
Dynamics Simulations ◽  
Small Single Crystal

ABSTRACTMany-body forces obtained by the Embedded-Atom Method (EAM) [41 are incorporated into the description of low energy collisions and surface ejection processes in molecular dynamics simulations of sputtering from metal targets. Bombardments of small, single crystal Cu targets (400–500 atoms) in three different orientations ({100}, {110}, {111}) by 5 keV Ar+ ions have been simulated. The results are compared to simulations using purely pair-wise additive interactions. Significant differences in the spectra of ejected atoms are found.

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