Early Stages of Sintering of Si3N4 Nanoclusters Via Parallel Molecular Dynamics

1995 ◽  
Vol 408 ◽  
Author(s):  
Kenji Tsuruta ◽  
Andrey Omeltchenko ◽  
Rajiv K. Kalia ◽  
Priya Vashishta
Keyword(s):  
Molecular Dynamics ◽  
Silicon Nitride ◽  
Neck Region ◽  
Md Simulations ◽  
Parallel Computers ◽  
Early Stages ◽  
Parallel Molecular Dynamics ◽  
Rapid Diffusion ◽  
A Chain

AbstractWe investigate early stages of sintering of silicon nitride (Si3N4) nanoclusters by molecular-dynamics (MD) simulations on parallel computers. Within 100 pico seconds, an asymmetric neck is formed between nanocrystals at 2,000K. In the neck region, there are more four-fold than three-fold coordinated Si atoms. In contrast, amorphous nanoclusters develop a symmetric neck, which has nearly the same number of three-fold and four-fold coordinated Si atoms. In the case of sintering among three nanoclusters, a chain-like structure forms in 200 pico seconds. The present study shows that sintering is driven by rapid diffusion of surface atoms and cluster rearrangement.

Structure, Mechanical Properties, and Dynamic Fracture in Nanophase Silicon Nitride via Parallel Molecular Dynamics

1996 ◽  
Vol 457 ◽  
Author(s):  
Kenji Tsuruta ◽  
Andrey Omeltchenko ◽  
Aiichiro Nakano ◽  
Rajiv K. Kalia ◽  
Priya Vashishta
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Grain Size ◽  
Silicon Nitride ◽  
Dynamic Fracture ◽  
Elastic Moduli ◽  
Md Simulations ◽  
Multiphase Model ◽  
Order Of Magnitude ◽  
Parallel Molecular Dynamics

ABSTRACTMillion-atom molecular-dynamics (MD) simulations are performed to study the structure, mechanical properties, and dynamic fracture in nanophase Si3N4. We find that intercluster regions are highly disordered: 50% of Si atoms in intercluster regions are three-fold coordinated. Elastic moduli of nanophase Si3N4 as a function of grain size and porosity are well described by a multiphase model for heterogeneous materials. The study of fracture in the nanophase Si3N4 reveals that the system can sustain an order-of-magnitude larger external load than crystalline Si3N4. This is due to branching and pinning of the crack front by nanoscale microstructures.

Parallel Molecular Dynamics With the Embedded Atom Method

1992 ◽  
Vol 291 ◽  
Author(s):  
Steven J. Plimpton ◽  
Bruce A. Hendrickson
Keyword(s):  
Molecular Dynamics ◽  
Md Simulations ◽  
Parallel Computers ◽  
Embedded Atom Method ◽  
Geometric Information ◽  
Parallel Methods ◽  
Embedded Atom ◽  
Multiple Data ◽  
Parallel Molecular Dynamics ◽  
Force Decomposition

ABSTRACTParallel computing offers new capabilities for using molecular dynamics (MD) to simulate larger numbers of atoms and longer time scales. In this paper we discuss two methods we have used to implement the embedded atom method (EAM) formalism for molecular dynamics on multiple-instruction/multiple-data (MIMD) parallel computers. The first method (atom-decomposition) is simple and suitable for small numbers of atoms. The second method (force-decomposition) is new and is particularly appropriate for the EAM because all the computations are between pairs of atoms. Both methods have the advantage of not requiring any geometric information about the physical domain being simulated. We present timing results for the two parallel methods on a benchmark EAM problem and briefly indicate how the methods can be used in other kinds of materials MD simulations.

Fracture in Silicon Nitride and Alumina thin Films: a Molecular Dynamics Study

1996 ◽  
Vol 446 ◽  
Author(s):  
Timothy J. Campbell ◽  
Aiichiro Nakano ◽  
Andrey Omeltchenko ◽  
Rajiv K. Kalia ◽  
Priya Vashishta
Keyword(s):  
Thin Films ◽  
Molecular Dynamics ◽  
Silicon Nitride ◽  
Large Scale ◽  
Md Simulations ◽  
Parallel Computers ◽  
Dynamic Correlations ◽  
Fracture Dynamics ◽  
Dynamic Charge ◽  
Effects Of Temperature

AbstractFracture in thin films of silicon nitride and alumina is investigated with large-scale multiresolution molecular-dynamics (MD) simulations on parallel computers. The simulations for alumina include dynamic charge transfer effects based on electronegativity equalization. Results for structural and dynamic correlations and the effects of temperature and orientation of film on fracture dynamics and morphology of fracture surfaces are presented.

Fracture of Nanophase Ceramics: A Molecular-Dynamics Study

1996 ◽  
Vol 457 ◽  
Author(s):  
Aiichiro Nakano ◽  
Rajiv K. Kalia ◽  
Andrey Omeltchenko ◽  
Kenji Tsuruta ◽  
Priya Vashishta
Keyword(s):  
Molecular Dynamics ◽  
Silicon Nitride ◽  
Load Balancing ◽  
Molecular Dynamics Simulations ◽  
Dynamic Fracture ◽  
Parallel Computers ◽  
Fracture Surfaces ◽  
Affine Structures ◽  
Dynamics Simulations ◽  
Multiscale Algorithms

ABSTRACTNew multiscale algorithms and a load-balancing scheme are combined for molecular-dynamics simulations of nanocluster-assembled ceramics on parallel computers. Million-atom simulations of the dynamic fracture in nanophase silicon nitride reveal anisotropie self-affine structures and crossover phenomena associated with fracture surfaces.

Early stages of sintering of silicon nitride nanoclusters: a molecular-dynamics study on parallel machines

1996 ◽  
Vol 33 (6) ◽  
pp. 441-446 ◽  
Author(s):  
K Tsuruta ◽  
A Omeltchenko ◽  
R. K Kalia ◽  
P Vashishta
Keyword(s):  
Molecular Dynamics ◽  
Silicon Nitride ◽  
Parallel Machines ◽  
Early Stages

Structure, Mechanical Properties, and Thermal Transport in Microporous Silicon Nitride Via Parallel Molecular Dynamics

1995 ◽  
Vol 408 ◽  
Author(s):  
Andrey Omeltchenko ◽  
Aiichiro Nakano ◽  
Rajiv K. Kalia ◽  
Priya Vashishta
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Silicon Nitride ◽  
Elastic Constants ◽  
Thermal Transport ◽  
Entire System ◽  
Amorphous Silicon Nitride ◽  
Parallel Molecular Dynamics ◽  
Dynamics Simulations

AbstractMolecular dynamics simulations are performed to investigate structure, mechanical properties, and thermal transport in amorphous silicon nitride under uniform dilation. As the density is lowered, we observe the formation of pores below ρ = 2.6 g/cc and at 2.0 g/cc the largest pore percolates through the entire system. Effects of porosity on elastic constants, phonons and thermal conductivity are investigated. Thermal conductivity and Young's modulus are found to scale as ρ1.5 and ρ3.6, respectively.

MASSIVELY DATA-PARALLEL MOLECULAR DYNAMICS

1992 ◽  
Vol 03 (04) ◽  
pp. 709-731
Author(s):  
ERNESTO BONOMI ◽  
MARCO TOMASSINI
Keyword(s):  
Molecular Dynamics ◽  
Heat Bath ◽  
Hard Core ◽  
Parallel Computers ◽  
Particle Systems ◽  
Data Parallel ◽  
Connection Machine ◽  
Large N ◽  
Parallel Molecular Dynamics ◽  
Dynamics Simulations

In light of present day data-parallel computers, an appraisal of molecular dynamics simulations of large N-particle systems, isolated or in contact with a heat-bath, is given. Special attention is focused 011 the Connection Machine CM-2. Particularly the cases of long-range potentials and impulsive hard-core interactions are discussed in detail. Data-parallel strategies including data distribution, communications and computation are presented and compared with well-known sequential approaches. The conclusion offered is that the methods described here are easy to design and offer the possibility of reasonably fast implementations for the reliable simulation of macroscopic samples of matter.

Dynamics And Morphology Of Cracks In Silicon Nitride Films: A Molecular Dynamics Study On Parallel Computers

1995 ◽  
Vol 409 ◽  
Author(s):  
Aiichiro Nakano ◽  
Rajiv K. Kalia ◽  
Priya Vashishta
Keyword(s):  
Molecular Dynamics ◽  
Silicon Nitride ◽  
Crack Propagation ◽  
Crystalline Silicon ◽  
Void Formation ◽  
Ceramic Materials ◽  
Parallel Computers ◽  
Kinetic Roughening ◽  
Fracture Surfaces ◽  
Silicon Nitride Films

AbstractMultiresolution molecular dynamics approach on parallel computers has been used to investigate fracture in ceramic materials. In microporous silica, critical behavior at fracture is analyzed in terms of pore percolation and kinetic roughening of fracture surfaces. Crack propagation in amorphous silicon nitride films is investigated, and a correlation between the speed of crack propagation and the morphology of fracture surfaces is observed. In crystalline silicon nitride films, temperature-assisted void formation in front of a crack tip slows down crack propagation.

Dislocation Emission at the Silicon/Silicon Nitride Interface: A Million Atom Molecular Dynamics Simulation on Parallel Computers

2000 ◽  
Vol 84 (2) ◽  
pp. 322-325 ◽  
Author(s):  
Martina E. Bachlechner ◽  
Andrey Omeltchenko ◽  
Aiichiro Nakano ◽  
Rajiv K. Kalia ◽  
Priya Vashishta ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Silicon Nitride ◽  
Molecular Dynamics Simulation ◽  
Parallel Computers ◽  
Dynamics Simulation ◽  
Dislocation Emission ◽  
Silicon Silicon
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