Computer Simulation of ao Screw Dislocations in Ni3Al

1990 ◽  
Vol 213 ◽  
Author(s):  
T.A. Parthasarathy ◽  
D.M. Dimiduk ◽  
C. Woodward ◽  
D. Diller
Keyword(s):  
Computer Simulation ◽  
Screw Dislocation ◽  
Elastic Anisotropy ◽  
Elastic Interaction ◽  
Embedded Atom Method ◽  
Interaction Torque ◽  
Embedded Atom ◽  
Reduced Height ◽  
Plane Step ◽  
Simulation Results

ABSTRACTDissociation of the ao<110> screw dislocation in Ni3Al was studied using the embedded atom method of computer simulation. The dissociation occurred predominantly along the {111} plane, however, a {001}-plane step occurred in the APB at the center of the configuration. When a pair of ao/2<110> superpartials initially separated in the {111} plane was relaxed, the step formed once again but with a reduced height. When the pair was relaxed from larger distances the step was not formed. The results indicate that the elastic interaction “torque” due to elastic anisotropy is responsible for the formation of the {001} APB step. When a stress was applied to these dislocation configurations by simulation, results confirmed that the step in the APB and the octahedral cross-slipped-core dissociations can be significant barriers to glide of the screw dislocation.

Structural Transformation of Aluminum Nanowires during Solidification

2010 ◽  
Vol 150-151 ◽  
pp. 160-163 ◽  
Author(s):  
Guo Rong Zhou ◽  
Zhong Quan Guo ◽  
Xin Ying Teng
Keyword(s):  
Boundary Condition ◽  
Computer Simulation ◽  
Cooling Rate ◽  
Structural Transformation ◽  
Amorphous Structure ◽  
Embedded Atom Method ◽  
Embedded Atom ◽  
Super Cell ◽  
Simulation Results ◽  
Embedded Atom Method Potential

The computer simulation of the structural evolutions of Al nanowires on cooling has been carried out based on the embedded atom method potential. The infinite Al nanowire was modeled by super-cell with a one-dimensionally periodical boundary condition along the [001] direction. The simulation results indicate that the microstructure of Al nanowires changed from amorphous to helical multi-shelled structure along with the drops of cooling rate. The helical multi-shelled structure possesses some features of amorphous structure, but it is more stable than the later. Moreover, the Al nanowires still keep the helical multi-shelled structure even if the cooling rate decreased to 1010 K/s.

Surface Steps: From Atomistics to Continuum

2002 ◽  
Vol 69 (4) ◽  
pp. 443-450 ◽  
Author(s):  
R. Kukta ◽  
A. Peralta ◽  
D. Kouris
Keyword(s):  
Additional Term ◽  
Elastic Interaction ◽  
Embedded Atom Method ◽  
Elastic Fields ◽  
Embedded Atom ◽  
Growth Modes ◽  
Surface Steps ◽  
Order Of Magnitude ◽  
Actual Geometry ◽  
Dominant Influence

The elastic interaction between surface steps biases growth and can have a dominant influence on growth modes of thin films. A new continuum solution is presented that takes into account the actual geometry of the steps. It is shown that even in the absence of external stress, the interaction energy contains a logarithmic dependence not previously reported in the literature. This additional term is of the same order of magnitude as the ones contained in the solution of Marchenko and Parshin that has been generally used during the past twenty years. Opposite and similar steps are investigated and closed-form expressions for the relevant elastic fields and interaction energies are derived. Results compare favorably with the ones obtained from embedded atom method (EAM) simulations and a recent elastic lattice model.

Planar fault energies and dislocation core spreading in B2 NiAl

1993 ◽  
Vol 8 (12) ◽  
pp. 3050-3058 ◽  
Author(s):  
Diana Farkas ◽  
Christophe Vailhe
Keyword(s):  
Computer Simulation ◽  
Screw Dislocation ◽  
Dislocation Core ◽  
Planar Fault ◽  
Restoring Forces ◽  
Simulation Results ◽  
Crystallographic Planes

We present computer simulation results for the planar faults involved in core spreading of 〈100〉 and 〈111〉 dislocations. Seven γ surfaces were computed for different crystallographic planes ({110}, {112}, {123}, {210}, {100}, {111}, and {122}). Stable APB's are observed in the {110} and {112} planes, but they are deviated from the exact 1/2a〈111〉 position. No other stable planar fault was observed. The fact that a stable minimum is observed deviated from the 1/2〈111〉 position suggests the possibility of different dissociation reactions for the 〈111〉 screw dislocation in the {110} and {112} planes. The fact that no other stable minima were observed in the γ surfaces indicates that no true core dissociation is expected for the 〈100〉 dislocations. We propose that dislocation core spreading in various planes can be understood in terms of the directions of lowest restoring forces observed for the corresponding γ surfaces.

Computer Simulation of Grain Boundary in BCC Fe by Embedded Atom Method

1996 ◽  
Vol 204-206 ◽  
pp. 227-232 ◽  
Author(s):  
Ryuzo Watanabe ◽  
Atsushi Nogami ◽  
T. Matsumiya
Keyword(s):  
Computer Simulation ◽  
Grain Boundary ◽  
Embedded Atom Method ◽  
Embedded Atom

Molecular Dynamics Simulations of the Impact of Energetic Cu Clusters on Cu and Ni Substrates

1990 ◽  
Vol 206 ◽  
Author(s):  
Horngming Hsieh ◽  
R.S. Averback
Keyword(s):  
Molecular Dynamics ◽  
Computer Simulation ◽  
Cluster Size ◽  
Solid Surfaces ◽  
Embedded Atom Method ◽  
Physical Processes ◽  
Embedded Atom ◽  
Cohesive Properties ◽  
Dynamics Simulations ◽  
The Impact

ABSTRACTThe interaction between energetic clusters of atoms and solid surfaces has been investigated by molecular-dynamics computer simulation. In this model, the impact of Cu clusters containing 4, 13 or 92 atoms and energies of 326 eV with Cu or Ni substrates is investigated. Either embedded-atom-method (EAM) potentials or a combination of Moliere and EAM potentials were employed for the calculations. The simulations reveal that different physical processes occur depending on cluster size and energy, and the cohesive properties of the substrate.

Atomistic Simulation Study of Controlled Nanostructure Patterning

2003 ◽  
Vol 775 ◽  
Author(s):  
Byeongchan Lee ◽  
Kyeongjae Cho
Keyword(s):  
Diffusion Barrier ◽  
Atomistic Simulation ◽  
Degrees Of Freedom ◽  
Embedded Atom Method ◽  
Surface Kinetics ◽  
Bulk Properties ◽  
Embedded Atom ◽  
Kinetics Of ◽  
Dissociation Barrier ◽  
Strain Dependent

AbstractWe investigate the surface kinetics of Pt using the extended embedded-atom method, an extension of the embedded-atom method with additional degrees of freedom to include the nonbulk data from lower-coordinated systems as well as the bulk properties. The surface energies of the clean Pt (111) and Pt (100) surfaces are found to be 0.13 eV and 0.147 eV respectively, in excellent agreement with experiment. The Pt on Pt (111) adatom diffusion barrier is found to be 0.38 eV and predicted to be strongly strain-dependent, indicating that, in the compressive domain, adatoms are unstable and the diffusion barrier is lower; the nucleation occurs in the tensile domain. In addition, the dissociation barrier from the dimer configuration is found to be 0.82 eV. Therefore, we expect that atoms, once coalesced, are unlikely to dissociate into single adatoms. This essentially tells that by changing the applied strain, we can control the patterning of nanostructures on the metal surface.

SIMULATION OF SOFT START OF SYNCHRONOUS ELECTRIC DRIVES

2019 ◽  
Author(s):  
Shakhboz Dadabaev
Keyword(s):  
Computer Simulation ◽  
Electric Drive ◽  
Water Supply Systems ◽  
Factors Affecting ◽  
Electric Drives ◽  
Soft Start ◽  
Simulation Results ◽  
Pumping Units ◽  
Negative Factors ◽  
Supply Systems

The main negative factors affecting the starting modes of synchronous electric drives of pumping units of irrigation water supply systems were identified, computer simulation of direct and soft start of synchronous electric drive was made, the simulation results are shown in graphs and a brief conclusion was made on the study.

Computer simulation to evaluate the economics of landfill gas recovery

1998 ◽  
Vol 38 (2) ◽  
pp. 201-208
Author(s):  
M. W. Milke
Keyword(s):  
Computer Simulation ◽  
Computer Program ◽  
Landfill Gas ◽  
Base Case ◽  
Simulation Tool ◽  
Hypothetical Case ◽  
Gas Recovery ◽  
Fixed Set ◽  
Key Variables ◽  
Simulation Results

A need exists for tools to improve evaluations of the economics of landfill gas recovery. A computer simulation tool is presented. It uses a spreadsheet computer program to calculate the economics for a fixed set of inputs, and a simulation program to consider variations in the inputs. The method calculates the methane generated each year, and estimates the costs and incomes associated with the recovery and sale of the gas. Base case results are presented for a city of 500,000. An uncertainty analysis for a hypothetical case is presented. The simulation results can help an analyst see the key variables affecting the economics of a project.

Sign in / Sign up

Export Citation Format

Share Document