scholarly journals Molecular Dynamics Study on Mechanical Properties of Nanopolycrystalline Cu–Sn Alloy

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7782
Author(s):  
Guodong Zhang ◽  
Junsheng Zhao ◽  
Pengfei Wang ◽  
Xiaoyu Li ◽  
Yudong Liu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Tensile Strength ◽  
Elastic Modulus ◽  
Dislocation Density ◽  
Strain Rate ◽  
Dynamics Simulation ◽  
Experimental Characterization ◽  
Tensile Process ◽  
Strength And Ductility

Molecular dynamics simulation is one kinds of important methods to research the nanocrystalline materials which is difficult to be studied through experimental characterization. In order to study the effects of Sn content and strain rate on the mechanical properties of nanopolycrystalline Cu–Sn alloy, the tensile simulation of nanopolycrystalline Cu–Sn alloy was carried out by molecular dynamics in the present study. The results demonstrate that the addition of Sn reduces the ductility of Cu–Sn alloy. However, the elastic modulus and tensile strength of Cu–Sn alloy are improved with increasing the Sn content initially, but they will be reduced when the Sn content exceeds 4% and 8%, respectively. Then, strain rate ranges from 1 × 109 s−1 to 5 × 109 s−1 were applied to the Cu–7Sn alloy, the results show that the strain rate influence elastic modulus of nanopolycrystalline Cu–7Sn alloy weakly, but the tensile strength and ductility enhance obviously with increasing the strain rate. Finally, the microstructure evolution of nanopolycrystalline Cu–Sn alloy during the whole tensile process was studied. It is found that the dislocation density in the Cu–Sn alloy reduces with increasing the Sn content. However, high strain rate leads to stacking faults more easily to generate and high dislocation density in the Cu–7Sn alloy.

Molecular dynamics study on the tensile properties of graphene/Cu nanocomposite

2017 ◽  
Vol 06 (03) ◽  
pp. 1750021 ◽  
Author(s):  
Jun Hua ◽  
Zhirong Duan ◽  
Chen Song ◽  
Qinlong Liu
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Tensile Strength ◽  
Elastic Modulus ◽  
Comparative Analysis ◽  
Strain Rate ◽  
Ultimate Strength ◽  
Strain Rates ◽  
Single Crystal Copper ◽  
Single Slice

In this paper, the mechanical properties, including elastic properties, deformation mechanism, dislocation formation and crack propagation of graphene/Cu (G/Cu) nanocomposite under uniaxial tension are studied by molecular dynamics (MD) method and the strain rate dependence is also investigated. Firstly, through the comparative analysis of tensile results of single crystal copper (Cu), single slice graphene/Cu (SSG/Cu) nanocomposite and double slice graphene/Cu (DSG/Cu) nanocomposite, it is found that the G/Cu nanocomposites have larger initial equivalent elastic modulus and tensile ultimate strength comparing with Cu and the more content of graphene, the greater the tensile strength of composites. Afterwards, by analyzing the tensile results of SSG/Cu nanocomposite under different strain rates, we find that the tensile ultimate strength of SSG/Cu nanocomposite increases with the increasing of strain rate gradually, but the initial equivalent elastic modulus basically remains unchanged.

scholarly journals Molecular Dynamics Simulation Study of the Mechanical Properties of Nanocrystalline Body-Centered Cubic Iron

Surfaces ◽  
2020 ◽  
Vol 3 (3) ◽  
pp. 381-391
Author(s):  
Jan Herman ◽  
Marko Govednik ◽  
Sandeep P. Patil ◽  
Bernd Markert
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Strain Rate ◽  
Tensile Tests ◽  
Dynamics Simulation ◽  
Uniaxial Tensile ◽  
Body Centered Cubic ◽  
Bcc Iron ◽  
Average Grain Size ◽  
Study Results

In the present work, the mechanical properties of nanocrystalline body-centered cubic (BCC) iron with an average grain size of 10 Å were investigated using molecular dynamics (MD) simulations. The structure has one layer of crystal grains, which means such a model could represent a structure with directional crystallization. A series of uniaxial tensile tests with different strain rates and temperatures was performed until the full rupture of the model. Moreover, tensile tests of the models with a void at the center and shear tests were carried out. In the tensile test simulations, peak stress and average values of flow stress increase with strain rate. However, the strain rate does not affect the elasticity modulus. Due to the presence of void, stress concentrations in structure have been observed, which leads to dislocation pile-up and grain boundary slips at lower strains. Furthermore, the model with the void reaches lower values of peak stresses as well as stress overshoot compared to the no void model. The study results provide a better understanding of the mechanical response of nanocrystalline BCC iron under various loadings.

Molecular Dynamics Study on Uniaxial Compression Transformation of Magnesium Alloy

NANO ◽  
2021 ◽  
pp. 2150118
Author(s):  
Qianhua Yang ◽  
Chun Xue ◽  
Zhibing Chu ◽  
Yugui Li ◽  
Lifeng Ma
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Phase Transformation ◽  
Magnesium Alloy ◽  
Strain Rate ◽  
Uniaxial Compression ◽  
Dynamics Simulation ◽  
Basic Knowledge ◽  
Transformation Mechanism ◽  
Different Temperatures

As a new method of calculating materials, molecular dynamics simulation can effectively reproduce the mechanical behavior of materials at the atomic level. In this paper, through the construction of the AZ31 magnesium alloy model, the uniaxial compression deformation of magnesium alloy at different temperatures and strain rate is simulated by molecular dynamics method, the mechanical properties and microstructure changes of magnesium alloy are analyzed, the phase transformation mechanism of magnesium alloy under uniaxial compression is revealed, and the effects of temperature and strain rate on the phase transformation of magnesium alloy are explored at the nanometer scale. It provides a theoretical basis and necessary basic knowledge for the design and development of Mg-based nanostructured alloys with excellent mechanical properties.

Optimization of Strength and Ductility in Ultra-Fine 304 Stainless Steel after Equal-Channel Angular Processing

2010 ◽  
Vol 667-669 ◽  
pp. 937-942 ◽  
Author(s):  
Z.J. Zheng ◽  
Yan Gao ◽  
Y. Gui ◽  
M. Zhu
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Strength ◽  
Stainless Steel ◽  
Dislocation Density ◽  
Vickers Hardness ◽  
304 Stainless Steel ◽  
Angular Pressing ◽  
Equal Channel Angular Processing ◽  
Strength And Ductility

The microstructure and mechanical properties of 304 stainless steel were investigated which was subjected to equal channel angular pressing (ECAP). Tensile strength, elongation, Vickers hardness of as-ECAPed and annealed ECAPed 304 stainless steel were systematically measured and compared and microstructure evolution during ECAP and ECAP+annealing was observed by OM and TEM. It was found that with the increasing of ECAP passes, the grain size of stainless steel was effectively refined to nanoscale, such as about 50 nm after 8 ECAP-passes. In addition, the dislocation density in ECAPed samplel increased greatly, consequently, the tensile strength and hardness of ECAPed 304 stainless steel increased and elongation decreased remarkably. After annealing at 600°C for 10 min，the ductility of ECAPed stainless steel was improved greatly while grains did not have obvious growth, and strength did not change much. The above results showed that the optimization of strength and ductility in ultra-fined 304 stainless steel can be achieved by appropriate ECAP plus annealing processes.

Effects of Vacancy Concentration and Temperature on Mechanical Properties of Single-Crystal γ-TiAl Based on Molecular Dynamics Simulation

2018 ◽  
Vol 37 (2) ◽  
pp. 113-120 ◽  
Author(s):  
Feng Ruicheng ◽  
Cao Hui ◽  
Li Haiyan ◽  
Rui Zhiyuan ◽  
Yan Changfeng
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Elastic Modulus ◽  
Molecular Dynamics Simulation ◽  
Vacancy Concentration ◽  
Dynamics Simulation ◽  
Evolution Process ◽  
Micro Cracks ◽  
Different Temperatures ◽  
External Forces

AbstractMolecular dynamics simulation is used to analyze tensile strength and elastic modulus under different temperatures and vacancy concentrations. The effects of temperature and vacancy concentration on the mechanical properties of γ-TiAl alloy are investigated. The results show that the ultimate stress, ultimate strain and elastic modulus decrease nonlinearly with increasing temperature and vacancy concentration. As the temperature increases, the plastic of material is reinforced. The influence of temperature on strength and elastic modulus is larger than that of vacancy concentration. The evolution process of vacancy could be observed clearly. Furthermore, vacancies with different concentrations develop into voids first as a function of external forces or other factors, micro cracks evolve from those voids, those micro cracks then converge to a macro crack, and fracture will finally occur. The vacancy evolution process cannot be observed clearly owing to the thermal motion of atoms at high temperature. In addition, potential energy is affected by both temperature and vacancy concentration.

Effects of defects and functional groups on graphene and nanotube thermoset epoxy-based nanocomposites mechanical properties using molecular dynamics simulation

2020 ◽  
pp. 096739112092907 ◽  
Author(s):  
Mahmoud Haghighi ◽  
Ali Khodadadi ◽  
Hossein Golestanian ◽  
Farshid Aghadavoudi
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Elastic Modulus ◽  
Functional Groups ◽  
Md Simulation ◽  
Matrix Material ◽  
Mixed Effects ◽  
Dynamics Simulation ◽  
The Matrix ◽  
Thermoset Epoxy

In this article, several thermoset epoxy-based nanocomposites are simulated using molecular dynamics (MD) simulation. Epoxy resin with 75% crosslinking ratio is modeled first and its properties are used as the matrix material mechanical properties. The effects of defects and functional groups on carbon nanotube- and nanographene-reinforced epoxy nanocomposites are investigated. To achieve our goals, various types of defects and functional groups are created on graphene and nanotube in the MD models. The defects consist of Stone–Wales, vacancy, and Adatom. In addition, functional groups consist of O, OH, COOH, and NH2. Mechanical properties of nanocomposites are determined and compared. Moreover, nanocomposites consisting of continuous and short reinforcements are modeled to investigate the effects of reinforcement length on nanocomposite mechanical properties. Numerical results show that defects and functional groups reduce the elastic modulus of the nanofillers and nanocomposites in continuous nanofiller-reinforced epoxy. However, in nanocomposites consisting of short nanofillers, defects and functional groups have mixed effects on nanocomposite mechanical properties.

scholarly journals Molecular Dynamics Simulation on Mechanical and Piezoelectric Properties of Boron Nitride Honeycomb Structures

Nanomaterials ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 1044 ◽  
Author(s):  
Lu Xie ◽  
Tianhua Wang ◽  
Chenwei He ◽  
Zhihui Sun ◽  
Qing Peng
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Boron Nitride ◽  
Strain Rate ◽  
Room Temperature ◽  
Piezoelectric Properties ◽  
Piezoelectric Effect ◽  
Failure Strain ◽  
Dynamics Simulation ◽  
Honeycomb Structures

Boron nitride honeycomb structure is a new three-dimensional material similar to carbon honeycomb, which has attracted a great deal of attention due to its special structure and properties. In this paper, the tensile mechanical properties of boron nitride honeycomb structures in the zigzag, armchair and axial directions are studied at room temperature by using molecular dynamics simulations. Effects of temperature and strain rate on mechanical properties are also discussed. According to the observed tensile mechanical properties, the piezoelectric effect in the zigzag direction was analyzed for boron nitride honeycomb structures. The obtained results showed that the failure strains of boron nitride honeycomb structures under tensile loading were up to 0.83, 0.78 and 0.55 in the armchair, zigzag and axial directions, respectively, at room temperature. These findings indicated that boron nitride honeycomb structures have excellent ductility at room temperature. Moreover, temperature had a significant effect on the mechanical and tensile mechanical properties of boron nitride honeycomb structures, which can be improved by lowering the temperature within a certain range. In addition, strain rate affected the maximum tensile strength and failure strain of boron nitride honeycomb structures. Furthermore, due to the unique polarization of boron nitride honeycomb structures, they possessed an excellent piezoelectric effect. The piezoelectric coefficient e obtained from molecular dynamics was 0.702   C / m 2 , which was lower than that of the monolayer boron nitride honeycomb structures, e = 0.79   C / m 2 . Such excellent piezoelectric properties and failure strain detected in boron nitride honeycomb structures suggest a broad prospect for the application of these new materials in novel nanodevices with ultrahigh tensile mechanical properties and ultralight-weight materials.

scholarly journals Using Molecular Dynamics Simulation to Analyze the Feasibility of Using Waste Cooking Oil as an Alternative Rejuvenator for Aged Asphalt

2021 ◽  
Vol 13 (8) ◽  
pp. 4373
Author(s):  
Lin Li ◽  
Cheng Xin ◽  
Mingyang Guan ◽  
Meng Guo
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Elastic Modulus ◽  
Shear Modulus ◽  
Bulk Modulus ◽  
Md Simulation ◽  
Waste Cooking Oil ◽  
Dynamics Simulation ◽  
Cooking Oil ◽  
Aged Asphalt

The purpose of this study was to investigate the regeneration effect of waste cooking oil (WCO) on aged asphalt with molecular dynamics (MD) simulation, comparing it with a rejuvenator. Firstly, the molecular models of virgin and aged asphalt were established by blending the four components of asphalt (saturate, aromatic, resin, and asphaltenes). Then, different dosages of the rejuvenator and WCO (6, 9, and 12%) were included in the aged asphalt model for its regeneration. After that, MD simulations were utilized for researching the mechanical and cohesive properties of the recycled asphalt, including its density, viscosity, cohesive energy density (CED), shear modulus (G), bulk modulus (K), and elastic modulus (E). The results show that the density values of the asphalt models were relatively lower than the existing experimental results in the literature, which is mostly attributed to the fact that the heteroatoms of the asphalt molecules were not considered in the simulation. On the other hand, the WCO addition decreased the viscosity, the shear modulus (G), the bulk modulus (K), and the elastic modulus (E) of the aged asphalt, improving its CED. Moreover, the nature of the aged asphalt was gradually restored with increasing rejuvenator or WCO contents. Compared with the rejuvenator, the viscosity of the aged asphalt was more effectively restored through adding WCO, while the effect of the CED and the mechanical properties recovery of the aged asphalt was relatively low. This implies that WCO could restore partial mechanical properties of aging asphalt, which proves the possibility of using WCO as an asphalt rejuvenator. Additionally, the MD simulation played an important role in understanding the molecular interactions among the four components of asphalt and the rejuvenator, which will serve as a guideline to better design a WCO rejuvenator and optimize its content.

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