Effect of grain boundary and defect on mechanical properties of bicrystalline graphene

2020 ◽  
pp. 2150141
Author(s):  
Meixia Xiao ◽  
Haiyang Song ◽  
Minrong An
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Yield Strength ◽  
Grain Boundary ◽  
Misorientation Angle ◽  
Deformation Behavior ◽  
Md Simulation ◽  
Compression Strain ◽  
Deformation Behaviors

The effects of grain boundary (GB) and defect on the deformation behaviors of graphene under tension or compression in directions perpendicular ([Formula: see text]-axis) or parallel ([Formula: see text]-axis) to GB are investigated by molecular dynamics (MD) simulation. The results show that the bicrystalline graphene can sustain more load under tension along [Formula: see text]-axis than along [Formula: see text]-axis, and that regardless of tensile directions, the yield strength of bicrystalline graphene with high misorientation angle is higher than that with low angle. Furthermore, we found that the effect of GB on the deformation behavior of graphene under compression strain along [Formula: see text]-axis is more obvious than that along [Formula: see text]-axis.

scholarly journals The Effects of Grain Boundary Misorientation on the Mechanical Properties and Mechanism of Plastic Deformation of Ni/Ni3Al: A Molecular Dynamics Study

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5715
Author(s):  
Jun Ding ◽  
Sheng-Lai Zhang ◽  
Quan Tong ◽  
Lu-Sheng Wang ◽  
Xia Huang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Plastic Deformation ◽  
Grain Boundary ◽  
Misorientation Angle ◽  
Interfacial Energy ◽  
Stacking Faults ◽  
Boundary Misorientation ◽  
Grain Boundary Misorientation ◽  
Mechanisms Of Plastic Deformation

The effects of grain boundary misorientation angle (θ) on mechanical properties and the mechanism of plastic deformation of the Ni/Ni3Al interface under tensile loading were investigated using molecular dynamics simulations. The results show that the space lattice arrangement at the interface is dependent on grain boundary misorientations, while the interfacial energy is dependent on the arrangement. The interfacial energy varies in a W pattern as the grain boundary misorientation increases from 0° to 90°. Specifically, the interfacial energy first decreases and then increases in both segments of 0–60° and 60–90°. The yield strength, elastic modulus, and mean flow stress decrease as the interfacial energy increases. The mechanism of plastic deformation varies as the grain boundary misorientation angle (θ) increases from 0° to 90°. When θ = 0°, the microscopic plastic deformation mechanisms of the Ni and Ni3Al layers are both dominated by stacking faults induced by Shockley dislocations. When θ = 30°, 60°, and 80°, the mechanisms of plastic deformation of the Ni and Ni3Al layers are the decomposition of stacking faults into twin grain boundaries caused by extended dislocations and the proliferation of stacking faults, respectively. When θ = 90°, the mechanisms of plastic deformation of both the Ni and Ni3Al layers are dominated by twinning area growth resulting from extended dislocations.

Mechanical properties and deformation behaviors of surface-modified silicon: a molecular dynamics study

2018 ◽  
Vol 54 (4) ◽  
pp. 3096-3110 ◽  
Author(s):  
Juan Chen ◽  
Junqin Shi ◽  
Zhi Chen ◽  
Meng Zhang ◽  
Weixiang Peng ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Deformation Behaviors ◽  
Surface Modified

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.

Study on Hardening Potential of Isostatic Pressed Beryllium

2020 ◽  
Vol 842 ◽  
pp. 199-204
Author(s):  
Boris Syrnev ◽  
Alexandr Revutskiy ◽  
Oksana Semilutskaya
Keyword(s):  
Mechanical Properties ◽  
Yield Strength ◽  
Grain Boundary ◽  
Elastic Limit ◽  
Hot Isostatic Pressing ◽  
Beryllium Oxide ◽  
Electron Microscopic ◽  
Research Results ◽  
Reinforcing Particles ◽  
Microscopic Studies

The effect of beryllium hardening has been studied. Beryllium is sintered by method of hot isostatic pressing (HIP), depending on the temperature of powders pressing. The research results of electron microscopic studies were the base for demonstrating formation of the hydraulic phase at the grain boundary of sintered beryllium and influence of the reinforcing phase on the mechanical properties of the HIP blank. The dependence of beryllium precision elastic limit and conventional yield strength from the size of the reinforcing particles of beryllium oxide has been found. The obtained equation provides a description of the “dispersion-grain-boundary" mechanism of isostatic pressed Beryllium hardening.

Effect of Organo-Shell Materials on Compatibility of the Hydrotalcite Flame Retardant in Ethylene Vinyl Acetate

2019 ◽  
Vol 19 (11) ◽  
pp. 7476-7486
Author(s):  
Jinze Du ◽  
Hongyan Zeng ◽  
Enguo Zhou ◽  
Bo Feng ◽  
Chaorong Chen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Tensile Strength ◽  
Vinyl Acetate ◽  
Md Simulation ◽  
Ethylene Vinyl Acetate ◽  
Flame Retardance ◽  
Strength Tests ◽  
Intrinsic Correlation

The microcapsule nanoparticles were prepared by in-situ copolymerization of hydrotalcites (MAH) with the polymer (MF, PF, PS and PU) monomers, respectively, where the MF-wrapped MAH (MAH@MF) had the best monodispersity. The composites of the microcapsules and EVA were prepared by incorporating the microcapsule nanoparticles into ethylene vinyl acetate (EVA), respectively. To further understand the intrinsic correlation between microcapsule fillers and EVA matrix, molecular dynamics (MD) simulation was introduced to qualitatively analyze the contribution of microcapsule fillers on improving compatibility and mechanical properties of the EVA matrix. The compatibility of microcapsule nanoparticles with EVA matrix were detected in sequence through SEM, DSC and tensile strength tests. And the combustion, thermal behavior and flame retardance were also characterized by TG analyses as well as LOI and UL-94 level. As a result, the MAH@MF filler had the best performances in improving the flame retardancy and mechanical properties among the microcapsule fillers, attributed to high compatibility of the MAH@MF and EVA matrix, which made uniform distribution of the MAH@MF filler due to the reciprocity of triazine functional ring with vinyl acetate linkages.

Ageing Effect on Mechanical Properties of Machined Nanostructures

2013 ◽  
Vol 683 ◽  
pp. 145-149
Author(s):  
Xing Lei Hu ◽  
Ya Zhou Sun ◽  
Ying Chun Liang ◽  
Jia Xuan Chen
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Yield Strength ◽  
Md Simulation ◽  
Fracture Strain ◽  
Machining Process ◽  
Ageing Process ◽  
Yield Strain ◽  
Before And After ◽  
Mc Simulation

Monte Carlo (MC) method and molecular dynamics (MD) are combined to analyze the influence of ageing on mechanical properties of machined nanostructures. Single crystal copper workpiece is first cut in MD simulation, and then the machined workpiece is used in MC simulation of ageing process, finally the tensile mechanical properties of machined nanostructures before and after ageing are investigated by MD simulation. The results show that machining process and ageing have obvious influence of tensile mechanical properties. After machining, the yield strength, yield strain, fracture strain and elastic modulus reduce by 36.02%, 28.86%, 20.79% and 7.16% respectively. However, the yield strength, yield strain and elastic modulus increase by 4.84%, 1.41% and 1.02% respectively, fracture strain reduce by 24.53% after ageing process. To research the ageing processes of machined nanostructures by MC simulation is both practical and meaningful.

scholarly journals MD INVESTIGATIONS FOR MECHANICAL PROPERTIES OF COPPER NANOWIRES WITH AND WITHOUT SURFACE DEFECTS

2012 ◽  
Vol 09 (01) ◽  
pp. 1240003 ◽  
Author(s):  
Y. T. GU ◽  
H. F. ZHAN
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Yield Strength ◽  
Yield Point ◽  
Surface Defects ◽  
Volume Ratio ◽  
Strain Rates ◽  
Copper Nanowires ◽  
Dislocation Source ◽  
Different Temperatures

Based on the molecular dynamics (MD) method, the single-crystalline copper nanowire with different surface defects is investigated through tension simulation. For comparison, the MD tension simulations of perfect nanowire are first carried out under different temperatures, strain rates, and sizes. It has concluded that the surface–volume ratio significantly affects the mechanical properties of nanowire. The surface defects on nanowires are then systematically studied in considering different defect orientation and distribution. It is found that the Young's modulus is the insensitive of surface defects. However, the yield strength and yield point show a significant decrease due to the different defects. Different defects are observed to serve as a dislocation source.

scholarly journals Deformation Behavior of Nanocrystalline Body-Centered Cubic Iron with Segregated, Foreign Interstitial: A Molecular Dynamics Study

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5351
Author(s):  
Ahmed Tamer AlMotasem ◽  
Matthias Posselt ◽  
Tomas Polcar
Keyword(s):  
Molecular Dynamics ◽  
Grain Boundary ◽  
Deformation Behavior ◽  
Large Scale ◽  
Grain Boundary Sliding ◽  
Carbon And Nitrogen ◽  
Embedded Atom ◽  
Boundary Sliding ◽  
Dynamics Simulations

In the present work, modified embedded atom potential and large-scale molecular dynamics’ simulations were used to explore the effect of grain boundary (GB) segregated foreign interstitials on the deformation behavior of nanocrystalline (nc) iron. As a case study, carbon and nitrogen (about 2.5 at.%) were added to (nc) iron. The tensile test results showed that, at the onset of plasticity, grain boundary sliding mediated was dominated, whereas both dislocations and twinning were prevailing deformation mechanisms at high strain. Adding C/N into GBs reduces the free excess volume and consequently increases resistance to GB sliding. In agreement with experiments, the flow stress increased due to the presence of carbon or nitrogen and carbon had the stronger impact. Additionally, the simulation results revealed that GB reduction and suppressing GBs’ dislocation were the primary cause for GB strengthening. Moreover, we also found that the stress required for both intragranular dislocation and twinning nucleation were strongly dependent on the solute type.

Mechanical properties of PGA at different water fractions – a molecular dynamics study

RSC Advances ◽  
2014 ◽  
Vol 4 (25) ◽  
pp. 12710-12715 ◽  
Author(s):  
Shin-Pon Ju ◽  
Wei-Chun Huang ◽  
Ken-Huang Lin ◽  
Hui-Lung Chen ◽  
Jenn-Sen Lin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Tensile Test ◽  
Md Simulation ◽  
Polyglycolic Acid ◽  
Water Fractions

The mechanical properties of polyglycolic acid (PGA) of different water weight fractions (1.7%, 2.9%, and 5%) were investigated by molecular dynamics (MD) simulation through a tensile test.

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