scholarly journals Atomistic Simulation for Rejuvenation of Cu-Zr Metallic Glasses by Strain

2019 ◽  
Author(s):  
Eunsung Jekal
Keyword(s):  
Metallic Glasses ◽  
Atomistic Simulation ◽  
Maximum Stress ◽  
Bond Angle ◽  
Annealed Sample ◽  
Angle Distribution ◽  
Shape Distortion ◽  
Bond Angle Distribution ◽  
Great Yield ◽  
Dynamics Simulations

Molecular dynamics simulations were carried out to investigate the atomic structure of a model Cu64Zr36 bulk metallic glass (BMG). It is found that the amount of icosahedral content of the system is significantly increased in a well relaxed structure. While we considered four connection types of vertex-, edge-, face-, and volume-sharing, the huge cluster in the relaxed samples mainly involve volume-type connection and exhibits a remarkable athermal plasticity that great stiffness and great yield strength compared to the as-quenched samples. In addition, the bond-angle distribution of annealed sample shows sharp peaks at specific bond angles which is an evidence of crystallized Laves-phase formed by icosahedral atoms, however the peaks are to be broaden after loading, which indicates decreasing amount of icosahedral content and their shape distortion. These results suggest that icosahedral content in a bulk metallic glasses plays a key role to determine the mechanical properties such as rigidity and maximum stress carrying capacity.

The Effect of Pressure on the Hydrogen Bond Structure of Liquid Water

1984 ◽  
Vol 39 (2) ◽  
pp. 179-185 ◽  
Author(s):  
G. Pálinkás ◽  
P. Bopp ◽  
G. Jancsó ◽  
K. Heinzinger
Keyword(s):  
Molecular Dynamics ◽  
Hydrogen Bond ◽  
Liquid Water ◽  
Bond Angle ◽  
Angle Distribution ◽  
Structure Of Water ◽  
Effect Of Pressure ◽  
Bond Angle Distribution ◽  
Dynamics Simulations ◽  
Force Potential

The results of molecular dynamics simulations of low and high pressure liquid water using a modified central force potential have been analyzed in order to study the effect of pressure on the hydrogen bond structure of water. The properties investigated and discussed include the hydrogen bond angle distribution, the O -O distance distribution between the neighbour molecules, the structure of the first coordination sphere in the high density liquid and the average number of hydrogen bonds.

Structural and Electronic Properties of Cu64Zr36 BMG by ab initio Molecular Dynamics

2013 ◽  
Vol 1517 ◽  
Author(s):  
Jonathan Galván-Colín ◽  
Ariel A. Valladares ◽  
Alexander Valladares ◽  
Renela M. Valladares
Keyword(s):  
Metallic Glasses ◽  
Pair Distribution Function ◽  
Bond Angle ◽  
Ab Initio Molecular Dynamics ◽  
Vibrational Properties ◽  
Angle Distribution ◽  
Electronic Density ◽  
Bond Angle Distribution ◽  
Structural And Electronic Properties ◽  
Radial Pair Distribution Function

ABSTRACTMuch attention has been given to bulk metallic glasses (BMG) in recent years, particularly those based on binary alloys due to the simplicity of their atomic composition. Although efforts to understand the atomistic features that give rise to their exceptional properties have been made, the electronic and vibrational properties have been disregarded. We undertook the task of simulating the Cu64Zr36 glassy metal using a supercell with 108 atoms and a different simulational approach: the undermelt-quench approach [1]. The structure was characterized by means of the radial (pair) distribution function and the bond-angle distribution and the electronic density of states was calculated. We find that our results agree well with experimental data.

AB INITIO MOLECULAR DYNAMICS SIMULATIONS ON LOCAL STRUCTURE AND ELECTRONIC PROPERTIES IN LIQUID MgxBi1-x ALLOYS

2013 ◽  
Vol 27 (06) ◽  
pp. 1350011 ◽  
Author(s):  
QING-HAI HAO ◽  
YU-WEI YOU ◽  
XIANG-SHAN KONG ◽  
C. S. LIU
Keyword(s):  
Molecular Dynamics ◽  
Local Structure ◽  
Order Parameter ◽  
Bond Order ◽  
Bond Angle ◽  
Pair Correlation ◽  
Ab Initio Molecular Dynamics ◽  
Angle Distribution ◽  
Bond Angle Distribution ◽  
Dynamics Simulations

The microscopic structure and dynamics of liquid Mg x Bi 1-x(x = 0.5, 0.6, 0.7) alloys together with pure liquid Mg and Bi metals were investigated by means of ab initio molecular dynamics simulations. We present results of structure properties including pair correlation function, structural factor, bond-angle distribution function and bond order parameter, and their composition dependence. The dynamical and electronic properties have also been studied. The structure factor and pair correlation function are in agreement with the available experimental data. The calculated bond-angle distribution function and bond order parameter suggest that the stoichiometric composition Mg 3 Bi 2 exhibits a different local structure order compared with other concentrations, which help us understand the appearance of the minimum electronic conductivity at this composition observed in previous experiments.

THE CORRELATION BETWEEN BOND ANGLE DISTRIBUTION AND THE COORDINATION OF SILICA LIQUID UNDER PRESSURE

2012 ◽  
Vol 26 (20) ◽  
pp. 1250117 ◽  
Author(s):  
L. T. VINH ◽  
N. V. HUY ◽  
P. K. HUNG
Keyword(s):  
Experimental Data ◽  
Molecular Dynamics ◽  
Bond Angle ◽  
Simple Expression ◽  
Dynamics Simulation ◽  
Angle Distribution ◽  
Bond Angle Distribution ◽  
Simulation Results ◽  
Substantial Change ◽  
Good Agreement

Molecular dynamics simulation is carried out for liquid SiO 2 at pressure ranged from zero to 30 GPa and by using BKS, Born–Mayer type and Morse–Stretch potentials. The constructed models reproduce well the experimental data in terms of mean coordination number, bond angle and pair radial distribution function. Furthermore, the density of all samples can be expressed by a linear function of fractions SiO x. It is found that the topology of units SiO x and linkages OSi y is unchanged upon compression although the liquid undergoes substantial change in its network structure. Consequently, the partial bond angle distribution for SiO x and OSi y is identical for all samples constructed by the same potential. This result allows to establishing a simple expression between total bond angle distribution (BAD) and fraction of SiO x and OSi y. The simulation shows a good agreement between the calculation and simulation results for both total O–Si–O and Si–O–Si BADs. This supports a technique to estimate amount of units SiO x and linkages OSi y on base of total Si–O–Si and O–Si–O BADs measured experimentally.

scholarly journals Structure and Correlation Between the Fraction of Structural Units and Bond Angle Distribution in Liquid B2 O3 Under Compression

2018 ◽  
Vol 2 (1) ◽  
Keyword(s):  
Pressure Range ◽  
Bond Angle ◽  
Structural Heterogeneity ◽  
Dynamics Simulation ◽  
Angle Distribution ◽  
Structural Units ◽  
Dynamical Heterogeneity ◽  
Heterogeneous Dynamics ◽  
Bond Angle Distribution ◽  
Spatially Heterogeneous Dynamics

Structure of network-forming liquid B2 O3 is investigated by Molecular dynamics simulation (MDS) at 2000K and in the 0-40 GPa pressure range (corresponding to the 1.71-3.04 g/cm3 density range). Results indicate that network structure of liquid B2 O3 comprises of basic structural units BO3 and BO4 . The topology and size of BO3 and BO4 units at different densities are identical. The O-B-O and B-O-B partial bond angle distributions (BADs) can be determined through the fraction of BO3 and BO4 units. Furthermore, the total BADs are directly related to the partial BADs and the fraction of structural units. It means the fraction of units BOX (X = 3,4) and units OBy (y = 2,3) can be determined from the experimental BADs. The spatial distribution of BO3 and BO4 units is not uniform but forming clusters of BO3 and BO4 . This leads to the polyamorphism in liquid B2 O3 . It also shows that the dynamical heterogeneity in liquid B2 O3 due to the lifetimes of BO3 and BO4 units are very different. The structural heterogeneity is origin of spatially heterogeneous dynamics in liquids B2 O3 .

Structure and Properties of the GeAsS Glasses from Ab initio Calculations

2014 ◽  
Vol 1035 ◽  
pp. 502-507
Author(s):  
Li An Chen
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Ab Initio ◽  
Bond Angle ◽  
Distribution Functions ◽  
Dynamics Simulation ◽  
Angle Distribution ◽  
Structure And Properties ◽  
Bond Angle Distribution ◽  
Pair Distribution Functions

The structure and properties of the GexAsxS100-2x have been studied by ab initio molecular dynamics simulation. By calculating the pair distribution functions, bond angle distribution functions, we analyze the structure and properties of the alloys. Calculations show that Ge and As are all well combined with S atoms. When x is smaller than 25.0 the binding increases with x , when x is larger than 25.0 the binding decreases with increasing x . The intervention of As atom does not affect the GeS2 formation in Ge40As40S80

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