Computational Study of Thermal Stabilities of Cu Nanorods at Atomic Scale

2013 ◽  
Vol 275-277 ◽  
pp. 1802-1805
Author(s):  
Duo Zhang ◽  
Yi Ju ◽  
Lin Zhang
Keyword(s):  
Structural Changes ◽  
Computational Study ◽  
Dynamic Properties ◽  
Biological Properties ◽  
Atomic Scale ◽  
Face Centered Cubic ◽  
Thermal Stabilities ◽  
Embedded Atom ◽  
Dynamics Simulations ◽  
Low Dimensional

Due to its unique mechanical，electrical，optical，chemical，catalytic and biological properties, nano-scale materials such as metal nanorods, have attracted wide attention. In these low-dimensional systems， Cu nanorods are ideal systems in novel electronic nano-devices and nano-catalysis. Nowadays the research of Cu nanorod has already become one of the central subjects in the nanomaterials science.In this paper, molecular dynamics simulations have been used to study structural changes of Cu nanorod during heating within the framework of embedded atom method (EAM) at the atomic scale，and their dynamics are also studied. During continuously heating processes, by studying the structure of the metal nanorods on the pair distribution function and energy changes，they are studied for the structural changes and dynamic properties of the Cu nanorods.The simulation results show that continuous changes of the Cu nanorods upon heating. At low temperatures, both the Cu nanorods have ordered arrangements with face-centered cubic structures. With increasing the temperature，the atom arrangements present the changes from the ordered state into the disordered state. It is also found that the size and shape of the nanorods have effect on the structural changes of these nanorods in the heating processes. The results show that the initial geometry of the nanorods greatly affect the structural change processes.

Simulating Structural Transformation of a Cu1553 Nanoparticle on Heating at Atomic Scale

2015 ◽  
Vol 817 ◽  
pp. 736-739
Author(s):  
Jing Zhang ◽  
Peng Yu
Keyword(s):  
Structural Transformation ◽  
Structural Changes ◽  
Distribution Functions ◽  
Atomic Scale ◽  
Embedded Atom Method ◽  
Embedded Atom ◽  
Different Temperatures ◽  
Dynamics Simulations ◽  
Pair Distribution Functions ◽  
Pair Analysis

By means of molecular dynamics simulations within the framework of embedded atom method, we observe the structural transformation of a Cu nanoparticle containing 1553 atoms at atomic scale on a heating series from 350K to 1200K at an increment of 50K. With increasing the temperature, the structural changes result in apparent increases in internal energy. Pair distribution functions (PDFs) and pair analysis (PA) technique as well as the atom packing at different temperatures are used to identify the local structural patterns during the melting of this particle.

Investigation of Crystalline and Amorphous Forms of Aluminum and Its Alloys: Computational Modeling and Experiment

NANO ◽  
2018 ◽  
Vol 13 (03) ◽  
pp. 1850026
Author(s):  
Sergey Shityakov ◽  
Norbert Roewer ◽  
Carola Y. Förster ◽  
Hai T. Tran ◽  
Wenjun Cai ◽  
...  
Keyword(s):  
Metal Structure ◽  
Dislocation Nucleation ◽  
Al Alloys ◽  
Atomic Scale ◽  
Face Centered Cubic ◽  
Stress Strain ◽  
The Face ◽  
Tension And Compression ◽  
Face Centered ◽  
Dynamics Simulations

The purpose of this study is to investigate polycrystalline lattices of aluminum (Al) under the stress–strain conditions in all-atom molecular dynamics simulations and Al alloys using X-ray diffraction. Isothermal uniaxial tension and compression of these polycrystalline lattices showed no dislocation nucleation peaks, which correspond only to the Al monocrystal form. The best tensile and compressive resistance characteristics were observed for a material with the highest grain number ([Formula: see text]) due to the significant reduction of the face-centered cubic lattice in the metal structure. This process is mainly driven by the gradual elevation of the system’s kinetic energy. In the experiment, the amorphous Al alloys with higher manganese composition (20.5%) were investigated, matching the simulated amorphous structures. Overall, the results suggest that the increase in number of grains in Al lattices diminishes the stress–strain impact due to a more disordered atomic-scale (amorphous) metal composition.

MOLECULAR DYNAMICS SIMULATIONS OF STRUCTURAL PROPERTIES OF CuNi ALLOYS DURING THE COOLING PROCESS AT HIGH PRESSURE

2020 ◽  
Vol 65 (10) ◽  
pp. 10-17
Author(s):  
Thao Nguyen Thi ◽  
Giang Bui Thi Ha ◽  
Linh Tran Phan Thuy ◽  
Hop Nguyen Van ◽  
Chung Pham Do ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
High Pressure ◽  
Molecular Dynamics Simulations ◽  
Sudden Change ◽  
Face Centered Cubic ◽  
Cooling Process ◽  
Embedded Atom ◽  
The Face ◽  
Face Centered ◽  
Dynamics Simulations

Molecular dynamics simulations of Cu80Ni20 (Cu:Ni = 8:2) model with the size of 8788 atoms have been carried out to study the structure and mechanical behavior at high pressure of 45 GPa. The interactions between atoms of the system were calculated by the Quantum Sutton-Chen embedded-atom potentials. The crystallization has occurred during the cooling process with a cooling rate of 0.01 K\ps. The temperature range of the phase transition is determined based on the sudden change of atomic potential during the cooling process. There is also a sudden change in the number of individual atoms in the sample. At a temperature of 300 K, both Ni and Cu atoms are crystallized into the face-centered cubic (FCC) and the hexagonal close-packed (HCP) phases, respectively. The mechanical characteristics of the sample at 300 K were also analyzed in detail through the determination of elastic modulus, number of atoms, and void distribution during the tensile process.

scholarly journals Structural Change of TiAl Alloy under Uniaxial Tension and Compression in the Direction: A Molecular Dynamics Study

Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1760
Author(s):  
Rizal Arifin ◽  
Fahmi Astuti ◽  
Malik Anjelh Baqiya ◽  
Yoyok Winardi ◽  
Yoga Arob Wicaksono ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
High Performance ◽  
Structural Changes ◽  
Compressive Loading ◽  
Initial Structure ◽  
Distribution Analysis ◽  
Face Centered Cubic ◽  
Tial Alloys ◽  
Tension And Compression ◽  
Dynamics Simulations

TiAl alloys can be used in aircraft and high-performance vehicle engines owing to their structural stability at high temperatures and their light weight. Although many studies have focused on developing this alloy material, there is still a lack of information about the changes in the structure of TiAl alloys under tensile and compressive loading. Therefore, we performed molecular dynamics simulations of the tensile and compressive loading of TiAl alloys in the <001> direction at temperatures of 10 and 300 K. From our simulation results, we found that the tensile and compressive strengths of TiAl alloys are significantly affected by temperature. It was found that TiAl alloys can withstand greater compression loading than tensile loading. This is due to the change in the crystal structure of TiAl alloys after being deformed to a strain of 0.4 by compressive loading, according to the analysis of structural changes under loading conditions. From the radial distribution analysis results, there was a change in the orientation of the face-centered cubic-like structure as it reached the maximum compressive stress compared to the initial structure.

Atomic Assembly of Thin Film Materials

2007 ◽  
Vol 539-543 ◽  
pp. 3528-3533
Author(s):  
X.W. Zhou ◽  
D.A. Murdick ◽  
B. Gillespie ◽  
J.J. Quan ◽  
Haydn N.G. Wadley ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Atomic Scale ◽  
Embedded Atom Method ◽  
Embedded Atom ◽  
Structures And Properties ◽  
Wide Range ◽  
Scale Structures ◽  
Kinetic Processes ◽  
Dynamics Simulations

The atomic-scale structures and properties of thin films are critically determined by the various kinetic processes activated during their atomic assembly. Molecular dynamics simulations of growth allow these kinetic processes to be realistically addressed at a timescale that is difficult to reach using ab initio calculations. The newest approaches have begun to enable the growth simulation to be applied for a wide range of materials. Embedded atom method potentials can be successfully used to simulate the growth of closely packed metal multilayers. Modified charge transfer ionic + embedded atom method potentials are transferable between metallic and ionic materials and have been used to simulate the growth of metal oxides on metals. New analytical bond order potentials are now enabling significantly improved molecular dynamics simulations of semiconductor growth. Selected simulations are used to demonstrate the insights that can be gained about growth processes at surfaces.

Molecular Dynamics Simulations of Pre-Crack Effects on Deformation and Failure Mechanisms for Pure Aluminum

2010 ◽  
Vol 452-453 ◽  
pp. 505-508
Author(s):  
Hua Yan Chen ◽  
Xiang Guo Zeng ◽  
Shu Sheng Xu
Keyword(s):  
Molecular Dynamics ◽  
Plastic Deformation ◽  
Crack Propagation ◽  
Pure Aluminum ◽  
Failure Mechanisms ◽  
Atomic Scale ◽  
Face Centered Cubic ◽  
Deformation And Failure ◽  
Dynamics Simulations ◽  
Fcc Structure

Micro-cracks which seriously affect the strength of metal materials always exist in metal or alloys during the manufacturing process. In order to investigate the pre-crack effects on deformation and failure mechanisms for pure aluminum at atomic scale, the plastic deformation processes of pure aluminum with face-centered cubic (fcc) crystal structure around the pre-crack tips at atomic scale were examined by means of molecular dynamics (MD) method. The Modified Embedded Atom Method (MEAM) potential was used to describe the interaction among atoms of pure aluminum. The crack propagation and failure processes for fcc structure were observed near the pre-crack tip zone. The calculation results reveal that the pre-crack blunting occurred at first, then the dislocation emitted at the pre-crack boundary and moved along with the specific direction obviously, eventually, cracks propagated along the crystallographic direction family of <110>. By means of VMD software, the graphic pictures of dislocation movement and crack propagation were obtained under different load conditions. The results and methodology given in this study are very significant for understanding more about plastic deformation and destruction at atomic scale for pure Aluminum with fcc structure.

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 Study on Interaction between Voids for Pure Aluminum

2010 ◽  
Vol 452-453 ◽  
pp. 845-848
Author(s):  
Shu Sheng Xu ◽  
Xiang Guo Zeng ◽  
Hua Yan Chen
Keyword(s):  
Molecular Dynamics ◽  
Pure Aluminum ◽  
Critical Distance ◽  
Atomic Scale ◽  
Embedded Atom Method ◽  
Face Centered Cubic ◽  
Embedded Atom ◽  
Modified Embedded Atom Method ◽  
Face Centered ◽  
The Impact

The voids in pure Aluminum always exit in the manufacturing process. The Modified Embedded Atom Method (MEAM) potential is employed in the molecular dynamics (MD) simulation at atomic scale to investigate the interaction between voids under the impact loading for pure Aluminum. The distance between the voids distributed along the loading orientation affects the failure mechanism seriously. The results show that there are 3 kinds of mechanisms with the change of the distance between voids: 1) coalescence takes place within a critical distance between voids under extra loading, 2) when the distance between voids reaches a certain value, each void cracks at 4 locations along with the slide direction <110> of face-centered cubic (fcc), respectively, 3) a stress shield zone appears when the ligament between the voids is at the size between the cases mentioned above, which brings out the phenomena that each of the voids cracks only at 2 locations, and no crack appeared at the stress shield zone.

A Molecular Dynamics Analysis of Surface Interference and Tip Shape and Size Effects on Atomic-Scale Friction

2005 ◽  
Vol 127 (3) ◽  
pp. 513-521 ◽  
Author(s):  
J. Yang ◽  
K. Komvopoulos
Keyword(s):  
Molecular Dynamics ◽  
Friction Coefficient ◽  
Atomic Scale ◽  
Front Face ◽  
Face Centered Cubic ◽  
Friction Forces ◽  
Face Centered ◽  
Dynamics Simulations ◽  
Insight Into ◽  
Shape And Size

Molecular dynamics simulations of a rigid diamond tip sliding on a face-centered-cubic copperlike substrate were performed in order to examine the dependence of the friction coefficient on the tip–substrate interference and the shape and size of the tip. For a square-base prismatic tip, the friction force is mainly due to interactions of atoms at the front face of the tip and substrate atoms ahead of the tip, while the normal force is due to interactions of atoms at the tip base and substrate atoms under the tip. However, for a pyramidal tip, both normal and friction forces are mainly due to interactions between atoms at the front face of the tip and substrate atoms in the vicinity of the sliding tip. Consequently, the friction coefficient is either sensitive (square-base prismatic tip) or insensitive (pyramidal tip) to the tip–substrate interference distance. In addition, tip size and orientation effects on the friction coefficient were observed with square- and triangle-base prismatic tips, respectively. Lower friction coefficients were obtained with a larger base area and edge-front sliding with a triangle-base prismatic tip. The results provide insight into atomic-scale friction anisotropies due to the effects of the tip size and shape and the tip–substrate interference.

Bonded Force Constant Derivation of Lysine-Arginine Cross-linked Advanced Glycation End-Products

2018 ◽  
Author(s):  
Anthony Nash ◽  
Nora H de Leeuw ◽  
Helen L Birch
Keyword(s):  
Molecular Dynamics ◽  
Force Constant ◽  
Computational Study ◽  
Force Constants ◽  
Quantum Mechanical ◽  
Advanced Glycation ◽  
Partial Charges ◽  
Cross Links ◽  
Complete Set ◽  
Dynamics Simulations

<div> <div> <div> <p>The computational study of advanced glycation end-product cross- links remains largely unexplored given the limited availability of bonded force constants and equilibrium values for molecular dynamics force fields. In this article, we present the bonded force constants, atomic partial charges and equilibrium values of the arginine-lysine cross-links DOGDIC, GODIC and MODIC. The Hessian was derived from a series of <i>ab initio</i> quantum mechanical electronic structure calculations and from which a complete set of force constant and equilibrium values were generated using our publicly available software, ForceGen. Short <i>in vacuo</i> molecular dynamics simulations were performed to validate their implementation against quantum mechanical frequency calculations. </p> </div> </div> </div>

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