Atomistic study of chemical effect on local structure in Mg-based metallic glasses

RSC Advances ◽  
2015 ◽  
Vol 5 (58) ◽  
pp. 46861-46868
Author(s):  
Q. Wang ◽  
J. H. Li ◽  
J. B. Liu ◽  
B. X. Liu
Keyword(s):  
Molecular Dynamics ◽  
Metallic Glasses ◽  
Local Structure ◽  
Interatomic Potential ◽  
Md Simulations ◽  
Chemical Effect ◽  
Chemical Effects ◽  
Atomistic Study

By applying a recently constructed interatomic potential, molecular dynamics (MD) simulations were performed to investigate the structural origin of chemical effects in Mg–Cu–Ni ternary metallic glasses.

Molecular Dynamics Simulations of Diffusion of O2 and N2 Penetrants in Polydimethylsiloxane-Based Nanocomposites

2012 ◽  
Vol 134 (2) ◽  
Author(s):  
Douglas E. Spearot ◽  
Alex Sudibjo ◽  
Varun Ullal ◽  
Adam Huang
Keyword(s):  
Molecular Dynamics ◽  
Polymer Composites ◽  
Diffusion Coefficients ◽  
Metal Particle ◽  
Interatomic Potential ◽  
Md Simulations ◽  
Coarse Grained ◽  
Cu Nanoparticles ◽  
Cu Nanoparticle ◽  
Nanoparticle Inclusions

Recently, metal particle polymer composites have been proposed as sensing materials for micro corrosion sensors. To design the sensors, a detailed understanding of diffusion through metal particle polymer composites is necessary. Accordingly, in this work molecular dynamics (MD) simulations are used to study the diffusion of O2 and N2 penetrants in metal particle polymer nanocomposites composed of an uncross-linked polydimethylsiloxane (PDMS) matrix with Cu nanoparticle inclusions. PDMS is modeled using a hybrid interatomic potential with explicit treatment of Si and O atoms along the chain backbone and coarse-grained methyl side groups. In most models examined in this work, MD simulations show that diffusion coefficients of O2 and N2 molecules in PDMS-based nanocomposites are lower than that in pure PDMS. Nanoparticle inclusions act primarily as geometric obstacles for the diffusion of atmospheric penetrants, reducing the available porosity necessary for diffusion, with instances of O2 and N2 molecule trapping also observed at or near the PDMS/Cu nanoparticle interfaces. In models with the smallest gap between Cu nanoparticles, MD simulations show that O2 and N2 diffusion coefficients are higher than that in pure PDMS at the lowest temperatures studied. This is due to PDMS chain confinement at low temperatures in the presence of the Cu nanoparticles, which induces low-density regions within the PDMS matrix. MD simulations show that the role of temperature on diffusion can be modeled using the Williams–Landel–Ferry equation, with parameters influenced by nanoparticle content and spacing.

Physical properties of high-temperature solid alkali chlorides by molecular dynamics simulation using a recent EIM interatomic potential

2019 ◽  
Vol 33 (10) ◽  
pp. 1950088 ◽  
Author(s):  
Xiandai Cui ◽  
Jiaoqun Zhu ◽  
Hong Xu ◽  
Xiaomin Cheng ◽  
Weibing Zhou
Keyword(s):  
Molecular Dynamics ◽  
Heat Capacity ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Interatomic Potential ◽  
Md Simulations ◽  
Dynamics Simulation ◽  
Experimental Values ◽  
Alkali Chlorides ◽  
Change Material

Thermophysical properties of phase change material NaCl and KCl were calculated using molecular dynamics (MD) simulations and a recent EIM interatomic potential. Density, thermal expansion coefficient, specific heat capacity were computed using equilibrium MD (EMD) simulations. The results are very close to the experimental values. The thermal conductivity was computed using two non-equilibrium MD (NEMD) methods and the results were compared with the experimental data. They appear to be relatively reasonable. Binary NaCl/KCl systems have also been investigated. The specific heat capacity with different compositions are calculated. They are very close with recent experimental results.

Retracted Article: Atomic-scale simulation to study the dynamical properties and local structure of Cu–Zr and Ni–Zr metallic glass-forming alloys

2016 ◽  
Vol 18 (10) ◽  
pp. 7169-7183 ◽  
Author(s):  
M. H. Yang ◽  
Y. Li ◽  
J. H. Li ◽  
B. X. Liu
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Metallic Glasses ◽  
Local Structure ◽  
Supercooled Liquids ◽  
Atomic Scale ◽  
Dynamics Simulation ◽  
Glass Forming ◽  
Retracted Article ◽  
Dynamical Properties

Molecular dynamics simulation with well-developed EAM potentials was carried out to investigate the transport properties and local atomic structure of Cu–Zr and Ni–Zr metallic glasses and supercooled liquids.

Annealing Kinetics of Single Displacement Cascades in Ni: An Atomic Scale Computer Simulation

1998 ◽  
Vol 540 ◽  
Author(s):  
A. Almazouzi ◽  
M. J. Caturla ◽  
T. Diaz de la Rubia ◽  
M. Victoria
Keyword(s):  
Interatomic Potential ◽  
Kinetic Monte Carlo ◽  
Scale Up ◽  
Md Simulations ◽  
Atomic Scale ◽  
Displacement Cascade ◽  
Atomistic Study ◽  
Kinetics Of

AbstractIn order to describe the long term evolution of the defects produced by a displacement cascade, Molecular dynamics (MD) and Kinetic Monte Carlo (KMC) methods are employed. Using an empirical Ni interatomic potential in MD, the damage resulting from primary knock-on atom (PKA) energies up to 30 keV has been simulated. The annealing kinetics and the fraction of freely migrating defects (FMD) are determined for each single displacement cascade, by a KMC code which is based on a set of parameters extracted mainly from MD simulations. It allows an atomistic study of the evolution of the initial damage over a time scale up to lOOs and the determination of the fraction of the defects that escape the KMC box, compared to those obtained by MD, as function of temperature and PKA energy. It has been found that this fraction depends strongly on the temperature but reaches a saturation value above stage V.

scholarly journals Molecular Dynamics Study on Lubrication Mechanism in Crystalline Structure between Copper and Sulfur

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Ken-ichi Saitoh ◽  
Tomohiro Sato ◽  
Masanori Takuma ◽  
Yoshimasa Takahashi ◽  
Ryuketsu Chin
Keyword(s):  
Molecular Dynamics ◽  
Shear Stress ◽  
Potential Function ◽  
Crystalline Structure ◽  
Interatomic Potential ◽  
Hexagonal Phase ◽  
Interatomic Interaction ◽  
Md Simulations ◽  
Shear Loading ◽  
Atomistic Modeling

To clarify the nanosized mechanism of good lubrication in copper disulfide (Cu2S) crystal which is used as a sliding material, atomistic modeling of Cu2S is conducted and molecular dynamics (MD) simulations are performed in this paper. The interatomic interaction between atoms and crystalline structure in the phase of hexagonal crystal of Cu2S are carefully estimated by first-principle calculations. Then, approximating these interactions, we originally construct a conventional interatomic potential function of Cu2S crystal in its hexagonal phase. By using this potential function, we perform MD simulation of Cu2S crystal which is subjected to shear loading parallel to the basal plane. We compare results obtained by different conditions of sliding directions. Unlike ordinary hexagonal metallic crystals, it is found that the easy-glide direction does not always show small shear stress for Cu2S crystal. Besides, it is found that shearing velocity affects largely the magnitude of averaged shear stress. Generally speaking, higher velocity results in higher resistance against shear deformation. As a result, it is understood that Cu2S crystal exhibits somewhat liquid-like (amorphous) behavior in sliding condition and shear resistance increases with increase of sliding speed.

A method for analyzing nanomechanical deformation of nanocrystalline Ni at higher timesteps than is possible in classical molecular dynamics

2006 ◽  
Vol 978 ◽  
Author(s):  
Vikas Tomar
Keyword(s):  
Molecular Dynamics ◽  
Monte Carlo ◽  
Strain Rate ◽  
Defect Formation ◽  
Interatomic Potential ◽  
Md Simulations ◽  
Classical Molecular Dynamics ◽  
Rate Dependent ◽  
Nanocrystalline Structures ◽  
Defect Nucleation

AbstractA majority of computational mechanical analyses of nanocrystalline materials have been carried out using classical molecular dynamics (MD). Due to the fundamental reason that the MD simulations must resolve atomic level vibrations, they cannot be carried out at the timescale of the order of microseconds. Additionally, MD simulations have to be carried out at very high loading rates (∼108 s−1) rarely observed in experiments. In this investigation a modified Hybrid Monte Carlo (HMC) method that can be used to analyze time-dependent (strain rate dependent) atomistic mechanical deformation of nanocrystalline structures at higher timescales than currently possible using MD is established. In this method there is no restriction on the size of MD timestep except that it must be such that to ensure a reasonable acceptance rate between consecutive Monte-Carlo (MC) time-steps. For the purpose of comparison HMC analyses of a nanocrystalline Ni sample at a strain rate of 109 s−1 with three different timesteps, viz. 2 fs, 4fs, and 8 fs, are compared with the analyses based on MD simulations at the same strain rate and a MD timestep of 2 fs. MD simulations of nanocrystalline Ni reproduce the defect nucleation and propagation results as well as strength values reported in the literature. In addition, HMC with timestep of 8 fs correctly reproduces defect formation and stress-strain response observed in the case of MD simulations with permissible timestep of 2 fs (for the interatomic potential used 2 fs is the highest MD timestep). Simulation time analyses show that by using HMC a saving of the order of 4 can be achieved bringing the atomistic analyses closer to the continuum timescales.

Local Atomic Arrangements of Pd-Based Bulk Metallic Glasses of the Metal-Metalloid Type Demonstrated by Molecular Dynamics Simulations

2010 ◽  
Vol 654-656 ◽  
pp. 1038-1041
Author(s):  
Akira Takeuchi ◽  
Akihisa Inoue
Keyword(s):  
Molecular Dynamics ◽  
Metallic Glasses ◽  
Md Simulations ◽  
Glass Forming Ability ◽  
Plastic Crystal ◽  
Glass Forming ◽  
Universal Feature ◽  
Crystal Model ◽  
Packed Structure ◽  
Dynamics Simulations

Molecular dynamics (MD) simulations based on a plastic crystal model (PCM) were performed for a Pd0.4Ni0.4P0.2 alloy in Metal-Metalloid (M-MLD) type of bulk metallic glass (BMG). Two kinds of clusters of cubeoctahedron capped with four half-octahedra and trigonal prism were used as initial atomic arrangements of the Pd0.4Ni0.4P0.2 alloy. Random rotations of clusters around their centers of gravity and subsequent structural relaxation vitrified the alloy. The high glass-forming ability of the Pd0.4Ni0.4P0.2 alloy is due to the critically-percolated, cluster-packed structure that is a universal feature for both M-MLD and M-M types of BMGs.

scholarly journals Hybrid machine learning assisted quantification of the compound internal and external uncertainties of graphene: Towards inclusive analysis and design

2021 ◽  
Author(s):  
Kritesh K. Gupta ◽  
Tanmoy Mukhopadhyay ◽  
Lintu Roy ◽  
Sudip Dey
Keyword(s):  
Machine Learning ◽  
Molecular Dynamics ◽  
Interatomic Potential ◽  
Md Simulations ◽  
First Principle ◽  
Reliability Of Results ◽  
Analysis And Design ◽  
Hybrid Machine ◽  
Inclusive Analysis

Reliability of results derived from molecular dynamics (MD) simulations depends on the adopted interatomic potential (IP), which is mathematically fitted to the data obtained from first principle approaches or experiments....

Dynamical Structure Factor and Vibrational Normal Modes of SiO2 Glass

1992 ◽  
Vol 291 ◽  
Author(s):  
Wei Jin ◽  
Rajiv K. Kalia ◽  
Priya Vashishta
Keyword(s):  
Molecular Dynamics ◽  
Structure Factor ◽  
Interatomic Potential ◽  
Inelastic Neutron Scattering ◽  
Normal Modes ◽  
Dynamic Structure ◽  
Md Simulations ◽  
Inelastic Neutron ◽  
Dynamical Structure ◽  
Dynamical Matrix

ABSTRACTWe study the atomic vibrational dynamics in silica glass (a-SiO2) using molecular-dynamics (MD) simulations and classical lattice dynamics method. The SiO2 glasses were generated by molecular-dynamics and steepest-descent quench (SDQ) using an effective interatomic potential consisting of two-body and three-body interactions. The frequency and eigenvectors of vibrational normal modes are obtained by diagonalization of the dynamical matrix. The partial and total vibrational density of states (DOS), bond-projected DOS, participation ratio (PR), and neutron-weighted dynamic structure factor are calculated. The results are compared with inelastic neutron scattering experiments on SiO2 glass.

Nanoscale Thermal Property of Amorphous SiC: A Molecular Dynamics Study

2007 ◽  
Vol 1022 ◽  
Author(s):  
Weiqiang Wang ◽  
Rajiv K. Kalia ◽  
Aiichiro Nakano ◽  
Priya Vashishta
Keyword(s):  
Molecular Dynamics ◽  
Interatomic Potential ◽  
Md Simulations ◽  
Temperature Profiles ◽  
Steady Temperature ◽  
Thermal Conductivity Model ◽  
Time Required ◽  
Amorphous Sic ◽  
Simulation Time ◽  
Thermal Conductivities

AbstractThermal properties of amorphous silicon carbide (a-SiC) at nanometric scales are studied by molecular dynamics (MD) simulations based on an empirical interatomic potential. A scalable parallel MD algorithm is used for studying systems as long as 30nm. To validate the potential, phonon density of states and specific heat of a-SiC are first calculated. Size effects are studied, and errors are estimated for the temperature profile for different system sizes. Simulation time required to achieve steady temperature profiles is also determined. Finally the thermal conductivities of a-SiC at various temperatures are calculated. The results show that thermal conductivities of a-SiC at nanometric scale also agree with Slack's minimum thermal conductivity model.

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