Simple Pd-Ag-H EAM Potentials for Hydrogen Storage Applications

2019 ◽  
Author(s):  
Robert Fuller ◽  
Iyad Hijazi
Keyword(s):  
Hydrogen Storage ◽  
Room Temperature ◽  
Nuclear Radiation ◽  
Miscibility Gap ◽  
Embedded Atom Method ◽  
Embedded Atom ◽  
Fitting Procedure ◽  
Atomic Simulations ◽  
Dynamics Simulations ◽  
Palladium Silver

Abstract The palladium–hydrogen system has attracted a vast amount of research interest. Palladium’s ability to absorb hydrogen at room temperature is reversible, and therefore suitable for many applications, including fuel cells, hydrogen storage, and nuclear radiation adsorption. Alloying palladium with silver can increase its performance in many applications as well as substantially lowering the materials cost. Palladium silver alloys can offer increased H diffusivity and a less pronounced miscibility gap with much improved mechanical properties over pure palladium. However, the relative insolubility of hydrogen in silver necessitates proper alloying of Pd-Ag to obtain the best combination of properties. Atomic simulations are useful in the evaluation of palladium-silver hydride systems as changes in composition can be more easily explored than with experiments. In this work we introduce fully analytical Embedded Atom Method (EAM) potentials for the Pd-Ag-H system, with fewer fitting parameters than previously developed EAM models. The central atom method is used, without the need for time-consuming molecular dynamics simulations during the fitting procedure.

An embedded-atom method interatomic potential for Pd–H alloys

2008 ◽  
Vol 23 (3) ◽  
pp. 704-718 ◽  
Author(s):  
X.W. Zhou ◽  
J.A. Zimmerman ◽  
B.M. Wong ◽  
J.J. Hoyt
Keyword(s):  
Computational Models ◽  
Mechanical Response ◽  
Hydrogen Diffusion ◽  
Interatomic Potential ◽  
Diffusion Mechanism ◽  
Miscibility Gap ◽  
Embedded Atom Method ◽  
Embedded Atom ◽  
Formidable Challenge ◽  
Embedded Atom Method Potential

Palladium hydrides have important applications. However, the complex Pd–H alloy system presents a formidable challenge to developing accurate computational models. In particular, the separation of a Pd–H system to dilute (α) and concentrated (β) phases is a central phenomenon, but the capability of interatomic potentials to display this phase miscibility gap has been lacking. We have extended an existing palladium embedded-atom method potential to construct a new Pd–H embedded-atom method potential by normalizing the elemental embedding energy and electron density functions. The developed Pd–H potential reasonably well predicts the lattice constants, cohesive energies, and elastic constants for palladium, hydrogen, and PdHx phases with a variety of compositions. It ensures the correct hydrogen interstitial sites within the hydrides and predicts the phase miscibility gap. Preliminary molecular dynamics simulations using this potential show the correct phase stability, hydrogen diffusion mechanism, and mechanical response of the Pd–H system.

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.

Atomistic Simulation Study of Mechanical Deformation of Al-Mg-Si Alloys

2021 ◽  
Vol 52 ◽  
pp. 149-163
Author(s):  
Hanae Chabba ◽  
Driss Dafir
Keyword(s):  
Deformation Behaviour ◽  
Compressive Loading ◽  
Embedded Atom Method ◽  
Stress Strain ◽  
Elasticity Limit ◽  
Embedded Atom ◽  
High Elasticity ◽  
Strain Relationship ◽  
Atomic Simulations ◽  
Strain Responses

Aluminum alloys have been attracting significant attention. Especially Al-Mg-Si alloys can exhibit an excellent balance between strength and ductility. Deformation mechanisms and microstructural evolution are still challenging issues. Accordingly, to describe how the type of phase influence mechanical behaviour of Al/Mg/Si alloys, in this paper atomic simulations are performed to investigate the uniaxial compressive behaviour of Al-Mg-Si ternary phases. The compression is at the same strain rate (3.1010 s−1); using Modified Embedded Atom Method (MEAM) potential to model the deformation behaviour. From these simulations, we get the total radial distribution function; the stress-strain responses to describe the elastic and plastic behaviors of GP-AlMg4Si6, U2-Al4Mg4Si4 and β-Al3Mg2Si6 phases. For a Detailed description of which phase influence hardness and ductility of these alloys; the mechanical properties are determined and presented. These stress-strain curves obtained show a rapid increase in stress up to a maximum followed by a gradual drop when the specimen fails by ductile fracture. From the results, it was found that GP-AlMg4Si6 & U2-Al4Mg4Si4 phases are brittle under uniaxial compressive loading while β-Al3Mg2Si6 phase is very ductile under the same compressive loading. The engineering stress-strain relationship suggests that β-Al3Mg2Si6 phase have high elasticity limit, ability to resist deformation and have the advantage of being highly malleable. Molecular dynamics software LAMMPS was used to simulate and build the Al-Mg-Si ternary system.

Study on the structural transition of CoNi nanoclusters using molecular dynamics simulations

2018 ◽  
Vol 32 (11) ◽  
pp. 1850133
Author(s):  
J. H. Xia ◽  
Xue-Mei Gao
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Structural Transition ◽  
Correction Function ◽  
Embedded Atom Method ◽  
Embedded Atom ◽  
Analysis Technique ◽  
Dynamics Simulations ◽  
Embedded Atom Method Potential ◽  
Pair Analysis

In this work, the segregation and structural transitions of CoNi clusters, between 1500 and 300 K, have been investigated using molecular dynamics simulations with the embedded atom method potential. The radial distribution function was used to analyze the segregation during the cooling processes. It is found that Co atoms segregate to the inside and Ni atoms preferably to the surface during the cooling processes, the Co[Formula: see text]Ni[Formula: see text] cluster becomes a core–shell structure. We discuss the structural transition according to the pair-correction function and pair-analysis technique, and finally the liquid Co[Formula: see text]Ni[Formula: see text] crystallizes into the coexistence of hcp and fcc structure at 300 K. At the same time, it is found that the frozen structure of CoNi cluster is strongly related to the Co concentration.

Effects of Hydrogen on the Fracture Properties of Σ9 and Σ11 Tilt Boundaries in Nickel

1992 ◽  
Vol 278 ◽  
Author(s):  
J.E. Angelo ◽  
W.W. Gerberich ◽  
N.R. Moody ◽  
S.M. Foiles
Keyword(s):  
Molecular Dynamics ◽  
Monte Carlo ◽  
Fracture Stress ◽  
Equilibrium Distribution ◽  
Embedded Atom Method ◽  
Far Field ◽  
Fracture Properties ◽  
Embedded Atom ◽  
Tilt Boundaries ◽  
Dynamics Simulations

AbstractIn this study, the Embedded Atom Method is combined with Monte Carlo and molecular dynamics simulations to study the fracture properties of Σ9 and Σ11 tilt boundaries in nickel. The Monte Carlo simulations are used to simulate the exposure of the bicrystal to a hydrogen environment at 300° C. These simulations establish the equilibrium distribution of hydrogen at the boundaries as a function of far-field concentration. The effect of the hydrogen on the fracture process is then studied with molecular dynamics. It will be shown that the fracture stress of the Σ9 boundary is affected over a wider range of far-field concentrations than the Σ11 boundary, although the Σ11 boundary shows that catastrophic failure occurs when the sample is charged beyond a certain far-field concentration.

Atomistic Simulations of the Mechanical Response of Copper/Polybutadiene Joints under Stress

2009 ◽  
Vol 1224 ◽  
Author(s):  
Fidel Orlando Valega Mackenzie ◽  
Barend J. Thijsse
Keyword(s):  
Mechanical Response ◽  
Polymer System ◽  
Atomistic Simulations ◽  
Embedded Atom Method ◽  
Embedded Atom ◽  
Numerical Studies ◽  
Universal Force Field ◽  
Dynamics Simulations ◽  
Metal Melting Point ◽  
Metal Polymer

AbstractMetal/polymer system joints are widely encountered nowadays in microscopic structures such as displays and microchips. In several critical cases they undergo thermal and mechanical loading, with contact failure due to fracture as a possible consequence. Because of their variety in nature and composition metal/polymer joints have become major challenges for experimental, theoretical, and numerical studies. Here we report on results of molecular dynamics simulations carried out to study the mechanical response of a metal/polymer joint, in this case the Cu/polybutadiene model system. The behavior of Cu and the cross-linked polybutadiene are modeled, respectively, by the Embedded Atom Method (EAM) and the Universal Force Field (UFF). Loading is applied under compression. Different potentials are used to describe the interactions in the metal/polymer interface, which allows us to qualitatively analyze possible mechanisms of failure in these joints, below the metal melting point and above the polymer glass transition temperatures.

scholarly journals A numerical fitting procedure for the embedded atom method interatomic potential and a bridged finite element-molecular dynamics method for large atomic systems

2021 ◽  
Author(s):  
Karthik Narayan
Keyword(s):  
Molecular Dynamics ◽  
Md Simulation ◽  
Embedded Atom Method ◽  
Discretization Scheme ◽  
Element Discretization ◽  
Atomic Systems ◽  
Embedded Atom ◽  
Fitting Procedure ◽  
Numerical Fitting ◽  
Eam Potential

This thesis presents a powerful numerical fitting procedure for generating Embedded Atom Method (EAM) inter-atomic potentials for pure Face Centred Cubic (FCC) and Body Centred Cubic (BCC) metals. The numerical fitting procedure involves assuming a reasonable parameterized form for a portion of the EAM potential, and then fitting the remaining portion to select thermal and elastic properties of the metal. Molecular Dynamics (MD) simulation is used to effect the fitting procedure. The procedure is used to generate an EAM potential for copper, an FCC metal. This resulting EAM potential is used to conduct MD simulations of perfect copper crystals containing voids of different geometries. Following this, a bridged Finite Element-Molecular Dynamics (FE-MD) method is presented, which can be used to simulate large atomic systems much more efficiently than MD simulation alone. The method implements a novel element discretization scheme proposed by the author that is so general that it can be applied to any system of objects interacting with each other via any potential (simple or complex, EAM or otherwise). This bridged FE-MD method is used to reanalyze the voids in the copper crystal lattice. The resulting virial stress increment patterns are found to agree remarkably with the earlier MD simulation results. Furthermore, the bridged FE-MD method is much quicker than the pure MD simulation. These two facts prove the power and usefulness of the bridged FE-MD method, and validate the proposed element discretization scheme

scholarly journals Quaternary Hydrides Pd1-y-zAgyCuzHx Embedded Atom Method Potentials for Hydrogen Energy Applications

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Chaonan Zhang ◽  
Robert Fuller ◽  
Iyad Hijazi ◽  
Keyword(s):  
Mechanical Properties ◽  
Carbon Monoxide Poisoning ◽  
Hydrogen Permeability ◽  
Sulfur Poisoning ◽  
Ternary Alloys ◽  
Miscibility Gap ◽  
Embedded Atom Method ◽  
Hydrogen Energy ◽  
Energy Applications ◽  
Embedded Atom

The Pd-H system has attracted extensive attention. Pd can absorb considerable amount of H at room temperature, this ability is reversible, so it is suitable for multiple energy applications. Pd-Ag alloys possess higher H permeability, solubility and narrower miscibility gap with better mechanical properties than pure Pd, but sulfur poisoning remains an issue. Pd-Cu alloys have excellent resistance to sulfur and carbon monoxide poisoning and hydrogen embrittlement, good mechanical properties, and broader temperature working environments over pure Pd, but relatively lower hydrogen permeability and solubility than pure Pd and Pd-Ag alloys. This suggests that alloying Pd with Ag and Cu to create Pd-Ag-Cu ternary alloys can optimize the overall performance and substantially lowers the cost. Thus, in this paper, we provide the first embedded atom method potentials for the quaternary hydrides Pd1-y-zAgyCuzHx. The fully analytical potentials are fitted utilizing the central atom method without performing time-consuming molecular dynamics simulations.

scholarly journals Effect of substrate temperature on quality of copper film catalyst substrate: A Molecular Dynamics Study

2017 ◽  
Vol 2 (2) ◽  
pp. 183 ◽  
Author(s):  
Rinaldo Marimpul
Keyword(s):  
Molecular Dynamics ◽  
Substrate Temperature ◽  
Film Growth ◽  
Copper Film ◽  
Deposition Process ◽  
Embedded Atom Method ◽  
Embedded Atom ◽  
Dynamics Simulations ◽  
Embedded Atom Method Potential

Copper film growth using thermal evaporation methods was studied using molecular dynamics simulations. The AlSiMgCuFe modified embedded atom method potential was used to describe interaction of Cu-Cu, Si-Si and Cu-Si atoms. Our results showed that the variations of substrate temperature affected crystal structure composition and surface roughness of the produced copper film catalyst substrate. In this study, we observed intermixing phenomenon after deposition process. The increasing of substrate temperature affected the increasing of the total silicon atoms had diffusion into copper film.

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