Is there a Limit to Nanoscale Mechanical Machining?

2013 ◽  
Vol 581 ◽  
pp. 316-321
Author(s):  
Akinjide O. Oluwajobi ◽  
Xun Chen
Keyword(s):  
Material Removal ◽  
Md Simulation ◽  
Depth Of Cut ◽  
Embedded Atom Method ◽  
Guiding Principle ◽  
Lennard Jones ◽  
Embedded Atom ◽  
Removal Processes ◽  
Mechanical Machining ◽  
Eam Potential

The Moores law which predicts that the number of transistors which can be integrated on the computer chip will double every 24 months and which has been the guiding principle for the advancement of the computer industry, is gradually reaching its limit. This is due to the limitations imposed by the laws of physics. Similarly, in the machining sector, Taniguchi predicted an increasing achievable machining precision as a function of time in the 1980s and this prediction is still on course. The question also is, is there a limit to machining and to material removal processes; and how far can this prediction be sustained? In this paper, the molecular dynamics (MD) simulation was employed to investigate this limit in the nanomachining of a copper workpiece with a diamond tool. The variation of the depth of cut used was from 0.01nm to 0.5nm. The Embedded Atom Method (EAM) potential was used for the copper-copper interactions in the workpiece; the Lennard-Jones (LJ) potential was used for the copper-carbon (workpiece-tool interface) interactions and the tool (carbon-carbon interactions) was modelled as deformable by using the Tersoff potential. It was observed from the simulation results that no material removal occurred between 0.01nm 0.25nm depth. At the depth of cut of 0.3nm, a layer of atoms appears to be removed or ploughed through by the tool. At a depth of cut less than 0.3nm, the other only phenomenon observed was the squeezing of the atom. The 0.3nm depth of cut is around the diameter of the workpiece-copper atom. So, it may be suggested that the limit of machining may be the removal of the atom of the workpiece.

scholarly journals A numerical fitting procedure for the embedded atom method interatomic potential and a bridged finite element-molecular dynamics method for large atomic systems

2021 ◽  
Author(s):  
Karthik Narayan
Keyword(s):  
Molecular Dynamics ◽  
Md Simulation ◽  
Embedded Atom Method ◽  
Discretization Scheme ◽  
Element Discretization ◽  
Atomic Systems ◽  
Embedded Atom ◽  
Fitting Procedure ◽  
Numerical Fitting ◽  
Eam Potential

This thesis presents a powerful numerical fitting procedure for generating Embedded Atom Method (EAM) inter-atomic potentials for pure Face Centred Cubic (FCC) and Body Centred Cubic (BCC) metals. The numerical fitting procedure involves assuming a reasonable parameterized form for a portion of the EAM potential, and then fitting the remaining portion to select thermal and elastic properties of the metal. Molecular Dynamics (MD) simulation is used to effect the fitting procedure. The procedure is used to generate an EAM potential for copper, an FCC metal. This resulting EAM potential is used to conduct MD simulations of perfect copper crystals containing voids of different geometries. Following this, a bridged Finite Element-Molecular Dynamics (FE-MD) method is presented, which can be used to simulate large atomic systems much more efficiently than MD simulation alone. The method implements a novel element discretization scheme proposed by the author that is so general that it can be applied to any system of objects interacting with each other via any potential (simple or complex, EAM or otherwise). This bridged FE-MD method is used to reanalyze the voids in the copper crystal lattice. The resulting virial stress increment patterns are found to agree remarkably with the earlier MD simulation results. Furthermore, the bridged FE-MD method is much quicker than the pure MD simulation. These two facts prove the power and usefulness of the bridged FE-MD method, and validate the proposed element discretization scheme

scholarly journals A numerical fitting procedure for the embedded atom method interatomic potential and a bridged finite element-molecular dynamics method for large atomic systems

2021 ◽  
Author(s):  
Karthik Narayan
Keyword(s):  
Molecular Dynamics ◽  
Md Simulation ◽  
Embedded Atom Method ◽  
Discretization Scheme ◽  
Element Discretization ◽  
Atomic Systems ◽  
Embedded Atom ◽  
Fitting Procedure ◽  
Numerical Fitting ◽  
Eam Potential

This thesis presents a powerful numerical fitting procedure for generating Embedded Atom Method (EAM) inter-atomic potentials for pure Face Centred Cubic (FCC) and Body Centred Cubic (BCC) metals. The numerical fitting procedure involves assuming a reasonable parameterized form for a portion of the EAM potential, and then fitting the remaining portion to select thermal and elastic properties of the metal. Molecular Dynamics (MD) simulation is used to effect the fitting procedure. The procedure is used to generate an EAM potential for copper, an FCC metal. This resulting EAM potential is used to conduct MD simulations of perfect copper crystals containing voids of different geometries. Following this, a bridged Finite Element-Molecular Dynamics (FE-MD) method is presented, which can be used to simulate large atomic systems much more efficiently than MD simulation alone. The method implements a novel element discretization scheme proposed by the author that is so general that it can be applied to any system of objects interacting with each other via any potential (simple or complex, EAM or otherwise). This bridged FE-MD method is used to reanalyze the voids in the copper crystal lattice. The resulting virial stress increment patterns are found to agree remarkably with the earlier MD simulation results. Furthermore, the bridged FE-MD method is much quicker than the pure MD simulation. These two facts prove the power and usefulness of the bridged FE-MD method, and validate the proposed element discretization scheme

Evaluation of Ni62Nb38 Bimetallic Glass Formation under Hydrostatically Pressurised Quenching

2020 ◽  
Vol 978 ◽  
pp. 436-445
Author(s):  
Mouparna Manna ◽  
Snehanshu Pal
Keyword(s):  
Molecular Dynamics ◽  
Md Simulation ◽  
Embedded Atom Method ◽  
Cooling Process ◽  
Forming Process ◽  
Glass Forming ◽  
Embedded Atom ◽  
Structural Evaluation ◽  
Fast Cooling ◽  
Compressive Pressure

In this present study, molecular dynamics (MD) simulation has been performed to investigate the influence of applied hydrostatic compressive and tensile pressure on glass forming process of Ni62Nb38 bimetallic glass using embedded atom method (EAM). During fast cooling (~10 K ps-1), tensile and compressive pressure has been applied having 0.001 GPa,0.01 GPa and 0.1 GPa magnitude. The glass transition temperature (Tg) for each pressurized (Tensile and Compressive nature) cooling case has been calculated and Tg is found to be dependent on both magnitude and nature of the pressure applied during cooling process.Voronoi cluster analysis has also been carried out to identify the structural evaluation during hydrostatically pressurised fast cooling process. In case of both hydrostatic tensile and compressive pressurised cooling processes, Tgincreases with the increase of pressure from 0.001 GPa to 0.1 GPa in magnitude.

The Infidence of Defect Concentrations on Migration Energies in AgZn Alloys

1988 ◽  
Vol 128 ◽  
Author(s):  
T. D. Andreadis ◽  
M. Rosen ◽  
J. M. Eridon ◽  
D. J. Rosen
Keyword(s):  
Linear Approximation ◽  
Embedded Atom Method ◽  
Local Defect ◽  
Migration Energy ◽  
New Model ◽  
Impurity Atoms ◽  
Embedded Atom ◽  
Defect Reactions ◽  
Eam Potential ◽  
Formation Energies

ABSTRACTMigration energies in Ag of vacancies, interstitials, Zn impurity atoms, interstitial-iipurity cumplexes, and vacancy-impurity complexes were calculated using Embedded Atom. Method (EAM) potentials in Molecular Statics calculations. A new Zn EAM potential was determined and used in these calculations. The dependence of the migration energies on local defect concentrations was determined in a linear approximation. Binding and formation energies of defects are also presented. A new model for the migration energy appropriate for defect reactions is introduced.

The effect of pressure on the elastic constants of Cu, Ag and Au: a molecular dynamics study

Open Physics ◽  
2006 ◽  
Vol 4 (4) ◽  
Author(s):  
Yasemin Çiftci ◽  
Kemal Çolakoğlu ◽  
Sefa Kazanç ◽  
SonerÖzgen
Keyword(s):  
Molecular Dynamics ◽  
Bulk Modulus ◽  
Elastic Constants ◽  
Md Simulation ◽  
Theoretical Calculations ◽  
Embedded Atom Method ◽  
Many Body ◽  
Effect Of Pressure ◽  
Embedded Atom ◽  
Function Expression

AbstractThis paper describes the effect of pressure on some the mechanical properties of transition metals Cu, Ag, and Au, such as elastic constants and bulk modulus. Using molecular dynamics (MD) simulation, the present study was carried out using the modified many-body Morse potential function expression in the framework of the Embedded Atom Method (EAM). The effect of pressure on equilibrium volume, elastic constants, and bulk modulus were determined, and found to be in agreement with other theoretical calculations and experimental data.

Molecular Dynamics Study of Pb Overlayer on Cu(100)

1990 ◽  
Vol 202 ◽  
Author(s):  
M. Karimi ◽  
P. Tibbits ◽  
D. Ila ◽  
I. Dalins ◽  
G. Vidali
Keyword(s):  
Molecular Dynamics ◽  
Structure Factor ◽  
Md Simulation ◽  
Dimensional Structure ◽  
Embedded Atom Method ◽  
Two Dimensional ◽  
Ordered Structure ◽  
Embedded Atom

ABSTRACTIsothermal-isobaric Molecular Dynamics (MD) simulation of a submonolayer Pb film in c(2×2) ordered structure adsorbed on a Cu(100) substrate showed retention of order to high T. The Embedded Atom Method (EAM) calculated the energy of atoms of overlayer and substrate. The time-averaged squared modulus of the two dimensional structure factor for the Pb overlayer measured the order of the overlayer. The results are for increasing T only, and require verification by simulated cooling.

The Effect of Interatomic Potentials on the Onset of Plasticity in the Molecular Dynamics (MD) Simulation of Nanometric Machining

2013 ◽  
Vol 535-536 ◽  
pp. 330-333 ◽  
Author(s):  
Akinjide Oluwajobi ◽  
Xun Chen
Keyword(s):  
Morse Potential ◽  
Md Simulation ◽  
Diamond Tool ◽  
Deformable Body ◽  
Depth Of Cut ◽  
Interatomic Potentials ◽  
Nanometric Machining ◽  
Force Ratio ◽  
Pile Up ◽  
Eam Potential

The effect of interatomic potentials on the onset of plastic deformation in the nanometric machining of a crystalline diamond tool on a crystalline copper workpiece, was investigated by using the MD simulation. Three potential pairs were used for the copper-copper (workpiece) and the copper-carbon (tool-workpiece interface) atomic interactions. For case 1, the Morse potential was used for both the copper-copper and the copper-carbon interactions; for case 2, the Embedded Atom Method (EAM) potential was used for the copper-copper interactions and the Morse potential was used for the copper-carbon interactions; and for case 3, the EAM potential was used for the copper-copper interactions and the Lennard-Jones (LJ) potential was used for the copper-carbon interactions. The diamond tool was modelled as a deformable body and the Tersoff potential was applied for the carbon-carbon interactions. From the simulation results, pile-up volume and the force ratio appear to indicate the onset of plasticity during the machining. The pile-up volume shows that ploughing starts from 0.25nm, 0.20 and 0.30nm depth of cut for case 1, case 2 and case 3 respectively and the formation of chips starts to occur from the depth of cut of 1.5nm for case 3. The force ratio also indicate the onset of ploughing at different depths of cut from 0.10nm-0.3nm.

Grain Boundary Migration in Nanocrystalline Iron

2007 ◽  
Vol 129 ◽  
pp. 145-150 ◽  
Author(s):  
Tomasz Wejrzanowski ◽  
M. Spychalski ◽  
Roman Pielaszek ◽  
Krzysztof Jan Kurzydlowski
Keyword(s):  
Boundary Migration ◽  
3D Models ◽  
Embedded Atom Method ◽  
Interface Motion ◽  
Embedded Atom ◽  
The Matrix ◽  
Nanocrystalline Iron ◽  
Eam Potential ◽  
The Relationship ◽  
Misorientation Angles

In this study a series of 3D models for curved [100] grain boundaries (GBs) in pure α-iron have been constructed. Each model consisted of a spherical grain, with an initial size of about 9 nm, surrounded by a large single-crystal. Different orientations have been assigned to the grain and the matrix in order to obtain interfaces with misorientation angles in the range of 5-45 degrees in steps of 5 degrees. The molecular dynamics with Embedded Atom Method (EAM) potential have been performed for investigation of the temporal changes in GB migration and grain rotations at temperature of 1000 K. The relationship between GB misorientation and its mobility has been found. It was also discovered that the density of the material decreases with a reduction of GB area. The effect of a triple junction on the interface motion has been also studied by introducing a bi-crystal matrix instead of a singlecrystal one. The results are discussed in terms of grain growth investigations in nanometals.

Molecular dynamics simulation of surface morphology during homoepitaxial growth of Copper

2019 ◽  
Vol 87 (3) ◽  
pp. 31301 ◽  
Author(s):  
Hicham El Azrak ◽  
Abdessamad Hassani ◽  
Abdelhadi Makan ◽  
Fouad Eddiai ◽  
Khalid Sbiaai ◽  
...  
Keyword(s):  
Thin Film ◽  
Molecular Dynamics ◽  
Surface Roughness ◽  
Surface Morphology ◽  
Md Simulation ◽  
Dynamics Simulation ◽  
Embedded Atom Method ◽  
Homoepitaxial Growth ◽  
Embedded Atom ◽  
Rough Surface Morphology

In this paper, molecular dynamics (MD) simulation of surface morphology during homoepitaxial growth of Copper was investigated. For this purpose, simulations of Cu deposition on the Cu(111) substrate with an incidence energy of 0.06 eV at 300K were performed using the embedded-atom method (EAM). The grown thin film on Cu(111) reveled a rough surface morphology. During deposition, the important fraction of atoms intended for the upper layers undergone a rising rate of about 40% starting from the 2nd period and continued to increase until 65%, while the lower level reached a permanent rate of only 25% by the 4th period. Otherwise, except at the first layer level, the lower layers are incomplete. This void in the lower layers has favored the growth of the upper layers until a rate of 143% and has accelerated their time appearance. Th incidence energy has favored the filling of lower layers by reducing this surface roughness. However, the temperature effect needs more relaxation time to fill the lower layers.

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