scholarly journals Molecular Dynamics Study of Bulk Properties of Polycrystalline NiTi

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1237
Author(s):  
Jeongwoo Lee ◽  
Yung C. Shin
Keyword(s):  
Molecular Dynamics ◽  
Grain Boundary ◽  
Md Simulations ◽  
Single Crystalline ◽  
Simulation Domain ◽  
Thermally Driven ◽  
Stress Boundary Conditions ◽  
Stress Boundary ◽  
Polycrystalline Structures ◽  
Atomic Stress

Molecular dynamics (MD) simulations were carried out to study the bulk polycrystalline properties of NiTi. Thermally driven phase transitions of NiTi between martensite and austenitewere simulated using single crystalline simulation domains. With external stress boundary conditions, MD simulation successfully predicted experimentally observed phase transformation temperatures of bulk polycrystalline. Elastic characteristics of NiTi martensite were simulated using polycrystalline simulation domains that consist of realistic disorientations and grain boundary structures. The existence of grain disorientation and grain boundary lowered the potential energy of the simulation domain, which led to more realistic elastic modulus prediction. Analysis of simulation domains that predicted realistic bulk polycrystalline properties showed that the major difference between single crystalline and polycrystalline structures is atomic stress distribution.

scholarly journals A molecular dynamics study on the tribological behavior of molybdenum disulfide with grain boundary defects during scratching processes

Friction ◽  
2020 ◽  
Author(s):  
Boyu Wei ◽  
Ning Kong ◽  
Jie Zhang ◽  
Hongbo Li ◽  
Zhenjun Hong ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Wear Resistance ◽  
Grain Boundary ◽  
Molybdenum Disulfide ◽  
Adhesion Strength ◽  
Misorientation Angle ◽  
Tribological Behavior ◽  
Md Simulations ◽  
Breaking Load ◽  
Indentation Process

AbstractThe effect of grain boundary (GB) defects on the tribological properties of MoS2 has been investigated by molecular dynamics (MD) simulations. The GB defects-containing MoS2 during scratching process shows a lower critical breaking load than that of indentation process, owing to the combined effect of pushing and interlocking actions between the tip and MoS2 atoms. The wear resistance of MoS2 with GB defects is relevant to the misorientation angle due to the accumulation of long Mo-S bonds around the GBs. Weakening the adhesion strength between the MoS2 and substrate is an efficient way to improve the wear resistance of MoS2 with low-angle GBs.

Molecular dynamics simulations of grain boundary diffusion in Al using embedded atom method potentials

1995 ◽  
Vol 10 (7) ◽  
pp. 1589-1592 ◽  
Author(s):  
Chun-Li Liu ◽  
S.J. Plimpton
Keyword(s):  
Molecular Dynamics ◽  
Grain Boundary ◽  
Boundary Diffusion ◽  
Md Simulations ◽  
Embedded Atom Method ◽  
Melting Temperatures ◽  
Embedded Atom ◽  
Pair Potentials ◽  
Dynamics Simulations ◽  
First Time

Molecular dynamics (MD) simulations of diffusion in a Σ5(310) [001] Al tilt grain boundary were performed using for the first time three different potentials based on the embedded atom method (EAM). The EAM potentials that produce more accurate melting temperatures also yield activation energies in better agreement with experimental data. Compared to pair potentials, the EAM potentials also give more accurate results.

scholarly journals Large-Scale Molecular Dynamics Simulations of Homogeneous Nucleation of Pure Aluminium

Metals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1217 ◽  
Author(s):  
Papanikolaou ◽  
Salonitis ◽  
Jolly ◽  
Frank
Keyword(s):  
Molecular Dynamics ◽  
Large Scale ◽  
Solidification Process ◽  
Md Simulations ◽  
Pure Aluminium ◽  
3 Dimensional ◽  
Hexagonal Close Packed ◽  
Simulation Domain ◽  
Dynamics Simulations ◽  
Insight Into

Despite the continuous and remarkable development of experimental techniques for the investigation of microstructures and the growth of nuclei during the solidification of metals, there are still unknown territories around this topic. The solidification in nanoscale can be effectively investigated by means of molecular dynamics (MD) simulations which can provide a deep insight into the mechanisms of the formation of nuclei and the induced crystal structures. In this study, MD simulations were performed to investigate the solidification of pure Aluminium and the effects of the cooling rate on the final properties of the solidified material. A large number of Aluminium atoms were used in order to investigate the grain growth over time and the formation of stacking faults during solidification. The number of face-centred cubic (FCC), hexagonal close-packed (HCP) and body-centred cubic (BCC) was recorded during the evolution of the process to illustrate the nanoscale mechanisms initiating solidification. The current investigation also focuses on the exothermic nature of the solidification process which has been effectively captured by means of MD simulations using 3 dimensional representations of the kinetic energy across the simulation domain.

Atomic simulations of GB sliding in pure and segregated bicrystals

2013 ◽  
Vol 1515 ◽  
Author(s):  
Motohiro Yuasa ◽  
Yasumasa Chino ◽  
Mamoru Mabuchi
Keyword(s):  
Molecular Dynamics ◽  
Electronic Structure ◽  
Grain Boundary ◽  
Charge Density ◽  
First Principles ◽  
Deformation Mode ◽  
Md Simulations ◽  
Bond Critical Point ◽  
First Principles Calculations ◽  
Atomic Simulations

ABSTRACTGrain boundary (GB) sliding is an important deformation mode in polycrystals, and it has been extensively investigated, for example, there are many studies on influences of the atomic geometry in the GB region. However, it is important to investigate GB sliding from the electronic structure of GB for deeper understandings of the sliding mechanisms. In the present work, we investigated the GBs sliding in pure and segregated bicrystals with classical molecular dynamics (MD) simulations and first-principles calculations. It is accepted that the sliding rate is affected by the GB energy. However, there was no correlation between the sliding rate and the GB energy in either the pure or the segregated bicrystals. First-principles calculations revealed that the sliding rate calculated by the MD simulations increases with decreasing minimum charge density at the bond critical point in the GB. This held in both the pure and segregated bicrystals. It seems that the sliding rate depends on atomic movement at the minimum charge density sites.

Role of CSL Boundaries on Displacement Cascades in β-SiC

2013 ◽  
Vol 1514 ◽  
pp. 43-48
Author(s):  
Prithwish K. Nandi ◽  
V. Ajay Annamareddy ◽  
Jacob Eapen
Keyword(s):  
Molecular Dynamics ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Neutron Irradiation ◽  
Md Simulations ◽  
Atomic Mobility ◽  
Statistical Nature ◽  
Displacement Cascades ◽  
Tilt Grain Boundary

ABSTRACTMolecular dynamics (MD) simulations are carried out to understand the mechanisms of damage production and recovery near grain boundaries in β-SiC under neutron irradiation. Our investigations show that the damage generated by radiation is reduced by the presence of a ∑9{122}[110] tilt grain boundary. Directional displacements which are averaged over an isoconfigurational ensemble are used to characterize the statistical nature of atomic mobility near the grain boundary.

scholarly journals Molecular dynamics simulations of nanoindentation and scratch in Cu grain boundaries

2017 ◽  
Vol 8 ◽  
pp. 2283-2295 ◽  
Author(s):  
Shih-Wei Liang ◽  
Ren-Zheng Qiu ◽  
Te-Hua Fang
Keyword(s):  
Molecular Dynamics ◽  
Grain Boundary ◽  
Molecular Dynamics Simulations ◽  
Grain Boundaries ◽  
Md Simulations ◽  
Barrier Effect ◽  
Cu Films ◽  
Simulation Results ◽  
Dynamics Simulations ◽  
Main Factor

The dynamic nanomechanical characteristics of Cu films with different grain boundaries under nanoindentation and scratch conditions were studied by molecular dynamics (MD) simulations. The type of grain boundary is the main factor in the control of the substrate atoms with respect to the size of dislocations since the existence of the grain boundary itself restricts the movement associated with dislocations. In this work, we analyzed the transverse and vertical grain boundaries for different angles. From the simulation results, it was found that the sample with a transverse grain boundary angle of 20° had a higher barrier effect on the slip band as compared to samples with other angles. Moreover, the nanoindentation results (i.e., indentation on the upper area) of the vertical grain boundary showed that the force was translated along the grain boundary, thereby producing intergranular fractures.

scholarly journals Molecular Dynamics Calculations of Grain Boundary Mobility in CdTe

Nanomaterials ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 552 ◽  
Author(s):  
Rodolfo Aguirre ◽  
Sharmin Abdullah ◽  
Xiaowang Zhou ◽  
David Zubia
Keyword(s):  
Molecular Dynamics ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Driving Forces ◽  
Md Simulations ◽  
Face Centered Cubic ◽  
Boundary Mobility ◽  
Grain Boundary Mobility ◽  
Different Temperatures ◽  
Lower Mobility

Molecular dynamics (MD) simulations have been applied to study mobilities of Σ3, Σ7 and Σ11 grain boundaries in CdTe. First, an existing MD approach to drive the motion of grain boundaries in face-centered-cubic and body-centered-cubic crystals was generalized for arbitrary crystals. MD simulations were next performed to calculate grain boundary velocities in CdTe crystals at different temperatures, driving forces, and grain boundary terminations. Here a grain boundary is said to be Te-terminated if its migration encounters sequentially C d · T e − C d · T e … planes, where “·” and “−” represent short and long spacing respectively. Likewise, a grain boundary is said to be Cd-terminated if its migration encounters sequentially T e · C d − T e · C d … planes. Grain boundary mobility laws, suitable for engineering time and length scales, were then obtained by fitting the MD results to Arrhenius equation. These studies indicated that the Σ3 grain boundary has significantly lower mobility than the Σ7 and Σ11 grain boundaries. The Σ7 Te-terminated grain boundary has lower mobility than the Σ7 Cd-terminated grain boundary, and that the Σ11 Cd-terminated grain boundary has lower mobility than the Σ11 Te-terminated grain boundary.

Efficient Treatment of Fixed and Induced Dipolar Interactions

2000 ◽  
Vol 653 ◽  
Author(s):  
Celeste Sagui ◽  
Thoma Darden
Keyword(s):  
Molecular Dynamics ◽  
Md Simulations ◽  
Lagrangian Formalism ◽  
Dipolar Interactions ◽  
Time Step ◽  
Efficient Treatment ◽  
Particle Mesh Ewald ◽  
Fixed Charges ◽  
Self Consistency ◽  
Induced Dipoles

AbstractFixed and induced point dipoles have been implemented in the Ewald and Particle-Mesh Ewald (PME) formalisms. During molecular dynamics (MD) the induced dipoles can be propagated along with the atomic positions either by interation to self-consistency at each time step, or by a Car-Parrinello (CP) technique using an extended Lagrangian formalism. The use of PME for electrostatics of fixed charges and induced dipoles together with a CP treatment of dipole propagation in MD simulations leads to a cost overhead of only 33% above that of MD simulations using standard PME with fixed charges, allowing the study of polarizability in largemacromolecular systems.

Split the Charge Difference in Two! a Rule of Thumb for Adding Proper Amounts of Ions in MD Simulations

2020 ◽  
Author(s):  
Matías R. Machado ◽  
Sergio Pantano
Keyword(s):  
Molecular Dynamics ◽  
Ionic Strength ◽  
Molecular Simulations ◽  
Md Simulations ◽  
Good Practices ◽  
Rule Of Thumb ◽  
Ionic Concentrations

<p> Despite the relevance of properly setting ionic concentrations in Molecular Dynamics (MD) simulations, methods or practical rules to set ionic strength are scarce and rarely documented. Based on a recently proposed thermodynamics method we provide an accurate rule of thumb to define the electrolytic content in simulation boxes. Extending the use of good practices in setting up MD systems is promptly needed to ensure reproducibility and consistency in molecular simulations.</p>

Assessing the Antimalarial Potentials of Phytochemicals: Virtual Screening, Molecular Dynamics and In-Vitro Investigations

2019 ◽  
Vol 16 (3) ◽  
pp. 291-300
Author(s):  
Saumya K. Patel ◽  
Mohd Athar ◽  
Prakash C. Jha ◽  
Vijay M. Khedkar ◽  
Yogesh Jasrai ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Structural Integrity ◽  
Md Simulations ◽  
Tylophora Indica ◽  
Multidrug Resistance Protein 1 ◽  
Receptor Complexes ◽  
Resistance Protein ◽  
Dynamics Simulations ◽  
Stable Trajectory

Background: Combined in-silico and in-vitro approaches were adopted to investigate the antiplasmodial activity of Catharanthus roseus and Tylophora indica plant extracts as well as their isolated components (vinblastine, vincristine and tylophorine). </P><P> Methods: We employed molecular docking to prioritize phytochemicals from a library of 26 compounds against Plasmodium falciparum multidrug-resistance protein 1 (PfMDR1). Furthermore, Molecular Dynamics (MD) simulations were performed for a duration of 10 ns to estimate the dynamical structural integrity of ligand-receptor complexes. </P><P> Results: The retrieved bioactive compounds viz. tylophorine, vinblastin and vincristine were found to exhibit significant interacting behaviour; as validated by in-vitro studies on chloroquine sensitive (3D7) as well as chloroquine resistant (RKL9) strain. Moreover, they also displayed stable trajectory (RMSD, RMSF) and molecular properties with consistent interaction profile in molecular dynamics simulations. </P><P> Conclusion: We anticipate that the retrieved phytochemicals can serve as the potential hits and presented findings would be helpful for the designing of malarial therapeutics.

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