Simulation of Stress Distribution and Mechanical Response of Metallic Glasses

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.

Simulation of Pressure Effects on Glasses

1996 ◽  
Vol 455 ◽  
Author(s):  
Y. Kogure ◽  
M. Doyama
Keyword(s):  
Shear Stress ◽  
Pressure Effects ◽  
Dynamics Simulation ◽  
Mechanical Relaxation ◽  
Embedded Atom Method ◽  
Atomic Interaction ◽  
Atomic Configuration ◽  
Embedded Atom ◽  
Model Crystal ◽  
Embedded Atom Method Potential

ABSTRACTGlass transition and effects of pressure and shear stress on atomic configuration are investigated by means of molecular dynamics simulation. An embedded atom method potential is used for the atomic interaction. A model crystal for Cu is melted and quenched to realize the glass state. Atomic configuration in the glass is examined through the radial distribution function. External stress is applied and displacement of atoms is monitored to investigate the mechanism of mechanical relaxation. Larger displacement of atoms is observed under a shear stress.

Simulation of Mechanical Response in Nanoparticles

2012 ◽  
Vol 184 ◽  
pp. 301-306 ◽  
Author(s):  
Yoshiaki Kogure ◽  
T. Kosugi ◽  
T. Nozaki
Keyword(s):  
Molecular Dynamics ◽  
Mechanical Response ◽  
The Other ◽  
Dynamics Simulation ◽  
Embedded Atom Method ◽  
Embedded Atom ◽  
Spherical Surfaces ◽  
Two Samples ◽  
Amorphous Structures ◽  
Embedded Atom Method Potential

Morphology and mechanical resonse of copper nanoparticles with defects have been simulated by means of molecular dynamics simulation. The embedded atom method potential for copper was used to express the interaction of atoms. Four types of model samples were prepared and about 37,000 atoms were contained in each sample. Two of them are cubic shape with {100} surfaces, in which vacancies or interstitials are introduced. The other two samples are once melted and solidified particles with nearly spherical surfaces. The atomic structure is controlled by cooling rate, and crystalline and amorphous structures are realized. Shear and tetragonal strains are applied to the samples and stress-strain relations for the samples are derived. Mechanical damping and internal friction were evaluated from the free decaying oscillations by releasing static strains.

Molecular-Dynamics Modelling of the Tensile Deformation of Helical Nanowires

2003 ◽  
Vol 778 ◽  
Author(s):  
K. Shintani ◽  
S. Kameoka
Keyword(s):  
Molecular Dynamics ◽  
Tensile Deformation ◽  
Axial Direction ◽  
Dynamics Simulation ◽  
Single Atom ◽  
Helical Structures ◽  
Embedded Atom ◽  
Atom Chain ◽  
Au Nanowires ◽  
Embedded Atom Method Potential

AbstractDeformations of Au nanowires of helical structures under enforced elongation are addressed by the molecular-dynamics simulation. The embedded-atom method potential is employed for calculating the interaction between Au atoms. Model nanowires of the two kinds of helicities are prepared. Before elongation, a model nanowire is equilibrated at a specified temperature. Then, the Au atoms at one end of the nanowire are translationally moved in the axial direction. The simulation results show that a model nanowire can be elongated to form a single-atom chain of Au atoms under some circumstances.

scholarly journals Dynamic characterization of Cu–Zr binary bulk metallic glasses: A molecular dynamics study

2017 ◽  
Vol 95 (12) ◽  
pp. 1189-1193
Author(s):  
Muhammad Imran ◽  
Fayyaz Hussain ◽  
Saba Altaf ◽  
Abdul Rehman ◽  
M. Arshad Javid ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Metallic Glasses ◽  
Compressive Loading ◽  
Bulk Metallic Glasses ◽  
Constant Strain Rate ◽  
Anomalous Behavior ◽  
Dynamics Simulation ◽  
Embedded Atom ◽  
Embedded Atom Method Potential

In the present study, a molecular dynamics simulation employing embedded atom method potential is performed to investigate the formation and characterization of CuZr bulk metallic glasses (BMGs). To elucidate the effect of component concentration of three samples of BMGs including Cu25Zr75, Cu50Zr50, and Cu75Zr25 that are formed by melt quenching. The local structure of BMGs is analyzed by means of radial distribution function and local atomic number density, ρ. The mechanical behavior of three compositions is investigated using uniaxial compressive loading at a constant strain rate. It is revealed from the results that yield strength increases with increasing Cu concentration. Thermal expansion of CuZr BMGs is examined and variation in length and volume is measured. The analysis revealed that Cu25Zr75, and Cu50Zr50 exhibited the typical expansion behavior while Cu75Zr25 showed an anomalous behavior.

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.

Glass Formation and Structural Study of Ti50Cu50 Alloy by Molecular Dynamics

2010 ◽  
Vol 638-642 ◽  
pp. 1665-1670 ◽  
Author(s):  
Jian Jun Pang ◽  
Ming Jen Tan ◽  
Anders W.E. Jarfors ◽  
P.D. Chuang
Keyword(s):  
Molecular Dynamics ◽  
Distribution Function ◽  
Metallic Glasses ◽  
Voronoi Tessellation ◽  
Supercooled Liquid ◽  
Dynamics Simulation ◽  
Embedded Atom Method ◽  
Atomic Configuration ◽  
Glass Forming ◽  
Embedded Atom

Ti-based metallic glasses (MGs) due to their relative low densities exhibit ultrahigh specific characteristics. In this article the glass-forming behavior and atomic structure of Ti50Cu50 MG were investigated through molecular dynamics simulation (MDS) using the general embedded-atom method (GEAM) potential. As observed experimentally, simulated Ti50Cu50 alloy undergoes three states on quenching: (i) equilibrium liquid; (ii) supercooled liquid and (iii) glassy solid. The atomic configuration of the glass was analysed based on the radial distribution function (RDF) and Voronoi tessellation (VT). It was found that there exist a variety of polyhedral units in Ti50Cu50 MG, where distorted icosohedral and bcc clusters are dominant.

scholarly journals The effect of electronic energy loss on the dynamics of thermal spikes in Cu

1991 ◽  
Vol 6 (3) ◽  
pp. 483-491 ◽  
Author(s):  
S. Prönnecke ◽  
A. Caro ◽  
M. Victoria ◽  
T. Diaz de la Rubia ◽  
M.W. Guinan
Keyword(s):  
Electronic Energy ◽  
Dynamics Simulation ◽  
Embedded Atom Method ◽  
Thermal Spike ◽  
Displacement Cascades ◽  
Embedded Atom ◽  
Ion Interactions ◽  
Electron Phonon Coupling ◽  
Coupling Time ◽  
Embedded Atom Method Potential

We present results of a molecular dynamics simulation study of the effect of electron-ion interactions on the dynamics of the thermal spike in Cu. Interatomic forces are described with a modified embedded atom method potential. We show that the electron-ion interaction acts to reduce the lifetime of the thermal spike and therefore the amount of atomic rearrangement that takes place in energetic displacement cascades in Cu. The results point toward the important effect that inelastic energy losses might have on the dynamics of displacement cascades in the subcascade energy regime where the lifetime of the thermal spike is expected to exceed the electron-phonon coupling time.

scholarly journals Crystallization of FCC and BCC Liquid Metals Studied by Molecular Dynamics Simulation

Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1532
Author(s):  
Dmitri V. Louzguine-Luzgin ◽  
Andrey I. Bazlov
Keyword(s):  
Molecular Dynamics ◽  
Structural Changes ◽  
Liquid Metals ◽  
Crystal Nucleation ◽  
Dynamics Simulation ◽  
Face Centered Cubic ◽  
Common Neighbor ◽  
Embedded Atom ◽  
Structure Observation ◽  
Embedded Atom Method Potential

The atomic structure variations on cooling, vitrification and crystallization processes in liquid metals face centered cubic (FCC) Cu are simulated in the present work in comparison with body centered cubic (BCC) Fe. The process is done on continuous cooling and isothermal annealing using a classical molecular-dynamics computer simulation procedure with an embedded-atom method potential at constant pressure. The structural changes are monitored with direct structure observation in the simulation cells containing from about 100 k to 1 M atoms. The crystallization process is analyzed under isothermal conditions by monitoring density and energy variation as a function of time. A common-neighbor cluster analysis is performed. The results of thermodynamic calculations on estimating the energy barrier for crystal nucleation and a critical nucleus size are compared with those obtained from simulation. The differences in crystallization of an FCC and a BCC metal are discussed.

Molecular-Dynamics Simulation of the Initial Period of Cluster Deposition

2002 ◽  
Vol 749 ◽  
Author(s):  
K. Shintani ◽  
T. Nakajima ◽  
Y. Taniguchi
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Initial Period ◽  
Equations Of Motion ◽  
Atomic Layer ◽  
Deposition Process ◽  
Dynamics Simulation ◽  
Soft Landing ◽  
Embedded Atom ◽  
Embedded Atom Method Potential

ABSTRACTThe initial periods of deposition process of metal clusters in the soft-landing regime are investigated by the molecular-dynamics simulation. The embedded-atom method potential is adopted for calculation of the interaction between metallic atoms. The predictor-corrector method for second-order differential equations is employed for integration of the equations of motion. A simulation begins with equilibration of clusters and a substrate at a specified temperature. The lowest atomic layer in the substrate is fixed and the next few atomic layers are set to be velocity-scaling layers during the deposition process. The periodic boundary conditions are imposed in the horizontal directions. A single cluster with no velocity is deposited on the substrate. The simulations are performed at different temperatures of the clusters and substrate and for different sizes of clusters. How the morphological transition of the deposited nanostructures is affected by these parameters is discussed.

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