The Effect of 555-777 Defect on Mechanical Properties of Graphene Nanoribbon

2021 ◽  
Vol 1032 ◽  
pp. 67-72
Author(s):  
Xiao Fei Ma ◽  
Xue Mei Sun ◽  
Rui Wang ◽  
Shuai Li
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Fracture Strength ◽  
Fracture Strain ◽  
Graphene Nanoribbons ◽  
Young's Modulus ◽  
Simulation Results ◽  
Armchair Graphene Nanoribbons ◽  
Dynamics Simulations ◽  
Zigzag Graphene Nanoribbons

In this study, the effects of 555-777 defect on Young’s modulus, fracture strength and fracture strain of armchair graphene nanoribbons (AGNRs) and zigzag graphene nanoribbons (ZGNRs) were investigated by using Molecular Dynamics simulations under uniaxial tension. The simulation results show that 555-777 defect significantly reduces the fracture strength and fracture strain of AGNRs and ZGNRs, but has little effect on Young's modulus. The influence of 555-777 defect on the mechanical properties of AGNRs is greater than that of ZGNRs. This study provides a better understanding of mechanical properties of graphene nanoribbons.

scholarly journals Effect of Defects on the Mechanical and Thermal Properties of Graphene

Nanomaterials ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 347 ◽  
Author(s):  
Maoyuan Li ◽  
Tianzhengxiong Deng ◽  
Bing Zheng ◽  
Yun Zhang ◽  
Yonggui Liao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Thermal Properties ◽  
Strain Rate ◽  
Young’S Modulus ◽  
Fracture Strength ◽  
Fracture Strain ◽  
Young's Modulus ◽  
Pristine Graphene ◽  
Mechanical And Thermal Properties

In this study, the mechanical and thermal properties of graphene were systematically investigated using molecular dynamic simulations. The effects of temperature, strain rate and defect on the mechanical properties, including Young’s modulus, fracture strength and fracture strain, were studied. The results indicate that the Young’s modulus, fracture strength and fracture strain of graphene decreased with the increase of temperature, while the fracture strength of graphene along the zigzag direction was more sensitive to the strain rate than that along armchair direction by calculating the strain rate sensitive index. The mechanical properties were significantly reduced with the existence of defect, which was due to more cracks and local stress concentration points. Besides, the thermal conductivity of graphene followed a power law of λ~L0.28, and decreased monotonously with the increase of defect concentration. Compared with the pristine graphene, the thermal conductivity of defective graphene showed a low temperature-dependent behavior since the phonon scattering caused by defect dominated the thermal properties. In addition, the corresponding underlying mechanisms were analyzed by the stress distribution, fracture structure during the deformation and phonon vibration power spectrum.

scholarly journals Effects of temperature and intrinsic structural defects on mechanical properties and thermal conductivities of InSe monolayers

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Van-Trung Pham ◽  
Te-Hua Fang
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Tensile Strength ◽  
Young’S Modulus ◽  
Fracture Strain ◽  
Young's Modulus ◽  
Vacancy Defect ◽  
Structural Defects ◽  
Effects Of Temperature ◽  
Dynamics Simulations

Abstract We conduct molecular dynamics simulations to study the mechanical and thermal properties of monolayer indium selenide (InSe) sheets. The influences of temperature, intrinsic structural defect on the tensile properties were assessed by tensile strength, fracture strain, and Young’s modulus. We found that the tensile strength, fracture strain, and Young’s modulus reduce as increasing temperature. The results also indicate that with the existence of defects, the stress is concentrated at the region around the vacancy leading to the easier destruction. Therefore, the mechanical properties were considerably decreased with intrinsic structural defects. Moreover, Young’s modulus is isotropy in both zigzag and armchair directions. The point defect almost has no influence on Young’s modulus but it strongly influences the ultimate strength and fracture strain. Besides, the effects of temperature, length size, vacancy defect on thermal conductivity (κ) of monolayer InSe sheets were also studied by using none-equilibrium molecular dynamics simulations. The κ significantly arises as increasing the length of InSe sheets. The κ of monolayer InSe with infinite length at 300 K in armchair direction is 46.18 W/m K, while in zigzag direction is 45.87 W/m K. The difference of κ values in both directions is very small, indicating the isotropic properties in thermal conduction of this material. The κ decrease as increasing the temperature. The κ goes down with the number of atoms vacancy defect increases.

A systematic study of the validation of Oliver and Pharr’s method

2007 ◽  
Vol 22 (12) ◽  
pp. 3385-3396 ◽  
Author(s):  
Siqi Shu ◽  
Jian Lu ◽  
Dongfeng Li
Keyword(s):  
Mechanical Properties ◽  
Strain Hardening ◽  
Young’S Modulus ◽  
Basic Assumption ◽  
Young's Modulus ◽  
Strain Hardening Exponent ◽  
The Finite Element Method ◽  
Solid Materials ◽  
Simulation Results ◽  
Depth Curves

Oliver and Pharr’s method (O&P’s method) is an efficient and popular way of measuring the hardness and Young’s modulus of many classes of solid materials. However, there exists a range of errors between the real values and the calculated values when O&P’s method is applied to materials not included in the basic assumption proposed initially. In this article, the dimensional analysis theorem and the finite element method are applied to evaluate errors for high elastic (E/σY → 5) to full plastic (E/σY→ 1000) materials with different strain-hardening exponents from 0 to 0.5. A new method is proposed to correct errors obtained using O&P’s method. The numerical simulation results show that the errors obtained using O&P’s method, given in the form of charts, are mainly dependent on the ratio of the reduced Young’s modulus to the yield stress (i.e., Er/σY) and the strain-hardening exponent, n, for an indenter with a fixed included angle. The two mechanical properties, which can be extracted from the load–depth curves of two indenters with different included angles, are used to correct the errors in the hardness and Young’s modulus of the indented materials produced by O&P’s method.

Mechanical Properties of Hydrogen Functionalized Graphyne - A Molecular Dynamics Investigation

2012 ◽  
Vol 472-475 ◽  
pp. 1813-1817 ◽  
Author(s):  
Yu Lin Yang ◽  
Zhe Yong Fan ◽  
Ning Wei ◽  
Yong Ping Zheng
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Young’S Modulus ◽  
Mechanical Performance ◽  
Young's Modulus ◽  
High Strength ◽  
Strength And Stiffness ◽  
Dynamics Simulations ◽  
Structure Engineering

In this paper the mechanical properties of a series of hydrogen functionalized graphyne are investigated through acting tensile loads on the monolayer networks. Molecular dynamics simulations are performed to calculate the fracture strains and corresponding maximum forces for pristine graphyne along both armchair and zigzag directions. Furthermore, hydrogen functionalized graphynes with different functionalization sites are analyzed to investigate the effect of functionlization on the mechanical performance. Finally, Young's modulus of all the investigated architectures are computed. The obtained results show that monolayer graphyne is mechanically stable with high strength and stiffness, and the mechanical performance can be tuned through structure engineering and functionalization.

Mechanical Properties of Transparent Polycrystalline Silicon Nitride

2006 ◽  
Vol 317-318 ◽  
pp. 305-308 ◽  
Author(s):  
Rak Joo Sung ◽  
Takafumi Kusunose ◽  
Tadachika Nakayama ◽  
Yoon Ho Kim ◽  
Tohru Sekino ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Silicon Nitride ◽  
Young’S Modulus ◽  
Fracture Strength ◽  
Polycrystalline Silicon ◽  
Volume Fraction ◽  
Young's Modulus ◽  
Β Phase ◽  
Α Phase

A novel transparent polycrystalline silicon nitride was fabricated by hot-press sintering with MgO and AlN as additives. The mixed powder with 3 wt.% MgO and 9 wt.% AlN was sintered at 1900oC for 1 hour under 30 MPa pressure in a nitrogen gas atmosphere. Transparent polycrystalline silicon nitride was successfully fabricated. The mechanical properties such as density, hardness, young’s modulus, fracture strength and fracture toughness were evaluated. The effect of α/β phase on the mechanical properties of transparent polycrystalline silicon nitride was investigated. The properties were changed depending on the amount of α/β phase. The hardness and Young's modulus increased with increasing the volume fraction of α-phase fraction as a reflection of the higher hardness of α-phase Si3N4. The fracture toughness and fracture strength decreased with decreasing the volume fraction of β-phase Si3N4.

Young's Modulus, Yield Strength and Fracture Strength of Microelements Determined by Tensile Testing

1998 ◽  
Vol 518 ◽  
Author(s):  
S. Greek ◽  
F. Ericson
Keyword(s):  
Mechanical Properties ◽  
Yield Strength ◽  
Young’S Modulus ◽  
Fracture Strength ◽  
Crystalline Silicon ◽  
Young's Modulus ◽  
Iron Alloy ◽  
Single Crystalline Silicon ◽  
Nickel Iron ◽  
Nickel Iron Alloy

AbstractSome mechanical properties of thin film microelements, e.g. fracture strength, depend on the manufacturing process, the load application as well as on size and shape of the microelements. Hence, the test structures that are used to determine mechanical properties should have dimensions of the same order of magnitude as an application structure, i.e. microelements must be used to accurately characterise MEMS. The fabrication of test structures must be realised in the same process as an intended application in order to give accurate results. Microelements are easily viewed in an SEM, but to be handled and tested in situ a micromanipulator was developed. Test structures were designed as released beams fixed to the substrate at one end, with a ring at the other. A high-precision testing unit was mounted on the micromanipulator next to the test structures. In the SEM, the testing unit was manoeuvred to grip the ring of the test structure beam and a tensile test of the beam was then executed. From the test data Young's modulus and fracture strength of polysilicon and single crystalline silicon were evaluated. Relative measurement of test structures with different beam lengths enabled Young's modulus to be evaluated with an accuracy of ±5%. Young's modulus was determined to 172±7 GPa for polysilicon and 142±9 GPa for single crystalline silicon in the <100> direction. The fracture surfaces were examined and compared. Young's modulus, yield strength and fracture strength of microelements made from electroplated nickel and nickel-iron alloy were also measured. Young's modulus was evaluated to 231±12 GPa for nickel and 155±8 GPa for nickel-iron alloy composed of 72 at% nickel and 28 at% iron.

Influence of Material Composition on Mechanical Properties and Fracture Behavior of Ceramic-Metal Composites

2005 ◽  
Vol 297-300 ◽  
pp. 1516-1521 ◽  
Author(s):  
Keiichiro Tohgo ◽  
Takayuki Kawaguchi
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Young’S Modulus ◽  
Fracture Strength ◽  
Vickers Hardness ◽  
Fracture Behavior ◽  
Volume Fraction ◽  
Young's Modulus ◽  
Metal Phase ◽  
Metal Composites

In order to estimate distribution of mechanical properties and fracture toughness in ceramic-metal functionally graded materials (FGMs), mechanical properties and fracture behavior have been investigated on non-graded ceramics-metal composites which correspond to each region of FGMs. The materials are fabricated by powder metallurgy using partially stabilized zirconia (PSZ) and stainless steel (SUS 304). Vickers hardness, Young’s modulus and bending fracture strength were examined on smooth specimens. The Vickers hardness of the composites continuously decreases with an increase in a volume fraction of SUS 304 metal phase, while the Young’s modulus and fracture strength exhibit low values in the composites with balanced composition of each phase. This suggests that the interfacial strength between the ceramic and metal phases is very low. Fracture toughness tests are conducted by three-point-bending on rectangular specimens with a sharp edgenotch. In contrast with the Young’s modulus and fracture strength, the fracture toughness obtained for the composites increases with an increase in a volume fraction of SUS 304 metal phase. The fracture toughness of the composites is slightly lower than that obtained previously by stable crack growth in a PSZ-SUS 304 FGM. The difference in fracture toughness between the composites and FGM seems to be attributed to the residual stress created during fabrication of the FGM.

scholarly journals The Mechanical Properties of Defective Graphyne

Crystals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 465 ◽  
Author(s):  
Shuting Lei ◽  
Qiang Cao ◽  
Xiao Geng ◽  
Yang Yang ◽  
Sheng Liu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Strain Rate ◽  
Young’S Modulus ◽  
Point Defects ◽  
Young's Modulus ◽  
Carbon Allotrope ◽  
Young’S Moduli ◽  
Potential Applications ◽  
Dynamics Simulations

Graphyne is a two-dimensional carbon allotrope with superior one-dimensional electronic properties to the “wonder material” graphene. In this study, via molecular dynamics simulations, we investigated the mechanical properties of α-, β-, δ-, and γ-graphynes with various type of point defects and cracks with regard to their promising applications in carbon-based electronic devices. The Young’s modulus and the tensile strength of the four kinds of graphyne were remarkably high, though still lower than graphene. Their Young’s moduli were insensitive to various types of point defects, in contrast to the tensile strength. When a crack slit was present, both the Young’s modulus and tensile strength dropped significantly. Furthermore, the Young’s modulus was hardly affected by the strain rate, indicating potential applications in some contexts where the strain rate is unstable, such as the installation of membranes.

scholarly journals Temperature effects on nanostructure and mechanical properties of single-nanoparticle thick membranes

2015 ◽  
Vol 181 ◽  
pp. 339-354 ◽  
Author(s):  
K. Michael Salerno ◽  
Gary S. Grest
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Mechanical Stiffness ◽  
Group Interactions ◽  
Single Nanoparticle ◽  
Alkane Chain ◽  
Dynamics Simulations ◽  
Increasing Temperature ◽  
End Group

The properties of mechanically stable single-nanoparticle (NP)-thick membranes have largely been studied at room temperature. How these membranes soften as nanoparticle ligands disorder with increasing temperature is unknown. Molecular dynamics simulations are used to probe the temperature dependence of the mechanical and nanostructural properties of nanoparticle membranes made of 6 nm diameter Au nanoparticles coated with dodecanethiol ligands and terminated with either methyl (CH3) or carboxyl (COOH) terminal groups. For methyl-terminated ligands, interactions along the alkane chain provide mechanical stiffness, with a Young's modulus of 1.7 GPa at 300 K. For carboxyl-terminated chains, end-group interactions are significant, producing stiffer membranes at all temperatures, with a Young's modulus of 3.8 GPa at 300 K. For both end-group types, membrane stiffness is reduced to zero at about 400 K. Ligand structure and mechanical properties of membranes at 300 K that have been annealed at 400 K are comparable to samples that do not undergo thermal annealing.

Characterization of Mechanical Properties of Silicon Nitride Thin Films for Space Applications

2003 ◽  
Vol 782 ◽  
Author(s):  
Wen-Hsien Chuang ◽  
Thomas Luger ◽  
Rainer K. Fettig ◽  
Reza Ghodssi
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Silicon Nitride ◽  
Young’S Modulus ◽  
Fracture Strength ◽  
Room Temperature ◽  
Young's Modulus ◽  
Space Environment ◽  
Bending Test ◽  
Space Applications

ABSTRACTMechanical properties of micro-electro-mechanical systems (MEMS) materials at cryogenic temperatures are investigated to extend MEMS devices into space applications. A helium-cooled measurement setup mimicking the outer space environment is developed and installed inside a focused-ion-beam (FIB) system. T-shape, low-stress LPCVD silicon nitride cantilevers suspended on a silicon substrate are fabricated as the test structures using bulk micromachining technique. A lead-zirconate-titanate (PZT) translator and a silicon diode are utilized as an actuator and a temperature sensor in the measurement setup, respectively. The resonant frequencies of an identical cantilever with different “milling masses” are measured to obtain the thickness and the Young's modulus. Additionally, a bending test is performed to determine the fracture strength. From the experiments, the Young's modulus of LPCVD silicon nitride thin films varies from 260.5 GPa ± 5.4 GPa at room temperature (298 K) to 266.6 GPa ± 4.1 GPa at 30 K, while the fracture strength ranges from 6.9 GPa ± 0.6 GPa at room temperature to 7.9 GPa ± 0.7 GPa at 30 K.

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