Temperature and Loading Rate Effect on the Load-Displacement Response of Metal-Metallic Glass (Al-Cu50Zr50) Layered Structure during Nano-Indentation

Molecular dynamics (MD) simulations of metal-metallic glass (Al-Cu50Zr50) multilayer during nanoindentation is carried out to investigate the load-displacement response, mechanical properties and deformation mechanisms. The indentation study is carried out at temperatures in the range of cryogenic to room temperature (10 K-300 K). The indenter speeds are varied between 0.5-5 Å/ps to study the effect of loading rate. The interaction between Al-Cu-Zr atoms are defined by EAM (Embedded Atom Method) potential. A sample size of 200 Å × 200 Å × 200 Å (in x y z-direction) comprising of 538538 atoms is used for nanoindentation. P P S boundary condition (BC) in x y z direction and NVT ensemble are used. We observed a peak load of 117 nN, at a temperature of 10 K with a loading rate of 5 Å/ps. We found that as the loading rate increase, the peak load also increases. As anticipated, the increase in temperature decreases the strength of the multilayer. The atomic displacement vector plots reveal that MG act as hurdles to the movement of dislocations nucleated at the interface.

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

Materials Science Forum ◽

10.4028/www.scientific.net/msf.706-709.1337 ◽

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.

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Atomistic Ordering in Body Centered Cubic Uranium-Zirconium Alloy

MRS Proceedings ◽

10.1557/opl.2013.517 ◽

2013 ◽

Vol 1514 ◽

pp. 27-35 ◽

Cited By ~ 3

Author(s):

Alex P. Moore ◽

Ben Beeler ◽

Michael Baskes ◽

Maria Okuniewski ◽

Chaitanya S. Deo

Keyword(s):

Binary Alloy ◽

Md Simulations ◽

High Temperature Phase ◽

Temperature Phase ◽

Body Centered Cubic ◽

Fast Reactors ◽

Embedded Atom ◽

Embedded Atom Method Potential ◽

New Generation ◽

Bcc Phase

ABSTRACTThe metallic binary-alloy fuel Uranium-Zirconium is important for the use of the new generation of advanced fast reactors. Uranium-Zirconium goes through a phase transition at higher temperatures to a (gamma) Body Centered Cubic (BCC) phase. The BCC high temperature phase is particularly important, since the BCC phase corresponds to the temperature range in which the fast reactors will operate. A semi-empirical MEAM (Modified Embedded Atom Method) potential is presented for Uranium-Zirconium. The physical properties of the Uranium-Zirconium binary alloy were reproduced using Molecular Dynamics (MD) simulations and Monte Carlo (MC) simulations with the MEAM potential. This is a large step in making a computationally acceptable fuel performance code.

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

Journal of Materials Research ◽

10.1557/jmr.2008.0090 ◽

2008 ◽

Vol 23 (3) ◽

pp. 704-718 ◽

Cited By ~ 57

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.

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Simulation of Stress Distribution and Mechanical Response of Metallic Glasses

MRS Proceedings ◽

10.1557/proc-554-37 ◽

1998 ◽

Vol 554 ◽

Author(s):

Y. Kogure ◽

M. Doyama

Keyword(s):

Stress Distribution ◽

Metallic Glasses ◽

Mechanical Response ◽

Local Density ◽

Glassy State ◽

Dynamics Simulation ◽

Single Atom ◽

Atomic Interaction ◽

Embedded Atom ◽

Embedded Atom Method Potential

AbstractMolecular dynamics simulation of the metallic glasses has been done. The embedded atom method potential function for copper is used to express the atomic interaction. The stress distribution in the glassy state is evaluated from specific volume occupied by single atom and local density in divided cells. The displacements of individual atom under the shear stress are calculated and the correlation between the displacements and the atomic volumes are investigated.

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

NANO ◽

10.1142/s1793292015500241 ◽

2015 ◽

Vol 10 (02) ◽

pp. 1550024 ◽

Cited By ~ 19

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.

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