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 Study on Dynamic Mechanical Properties and Constitutive Model Construction of TC18 Titanium Alloy

Metals ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 44 ◽  
Author(s):  
Changming Zhang ◽  
Anle Mu ◽  
Yun Wang ◽  
Hui Zhang
Keyword(s):  
Mechanical Properties ◽  
Titanium Alloy ◽  
Flow Stress ◽  
Yield Strength ◽  
Constitutive Model ◽  
Testing Machine ◽  
Dynamic Mechanical Properties ◽  
Stress Strain ◽  
Dynamic Mechanical ◽  
Different Temperatures

In order to investigate the static and dynamic mechanical properties of TC18 titanium alloy, the quasi-static stress–strain curve of TC18 titanium alloy under room temperature was obtained by DNS 100 electronic universal testing machine (Changchun Institute of Mechanical Science Co., Ltd., Changchun, China). Meanwhile, the flow stress–strain curves under different temperatures and strain rates are analyzed by split Hopkinson pressure bar (SHPB) device with synchronous assembly system. On the basis of the two experimental data, the JC constitutive model under the combined action of high temperature and impact load is established using the linear least squares method. The results show the following: the yield strength and flow stress of TC18 titanium alloy increase slowly with the increase of the strain rate, and the strain value corresponding to the yield strength is reduced. With the increase of strain, the flow stress increases at first and then decreases at different temperatures. The strain value corresponding to the transition point rises with the temperature increase, and the corresponding stress value remains basically unchanged. With the increase of experimental temperature, the flow stress shows a downward trend, and the JC constitutive model can predict the plastic flow stress well.

Thermal Stability of Mechanical Properties of Copper after Equal-Channel Angular Pressing

2008 ◽  
Vol 584-586 ◽  
pp. 960-965 ◽  
Author(s):  
Tamara Kravchenko ◽  
Alexander Korshunov ◽  
Natalia Zhdanova ◽  
Lev Polyakov ◽  
Irina Kaganova
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Tensile Strength ◽  
Chemical Composition ◽  
Yield Strength ◽  
Equal Channel Angular Pressing ◽  
Angular Pressing ◽  
Different Temperatures ◽  
Thermal Stability Of

Annealed oxygen-free and tough-pitch copper samples have been processed by equalchannel angular pressing (ECAP) by route BC. The samples included 8 x 8 mm section pieces and a 40 mm diameter bar. Thermal stability was assessed based on the changes in the standard mechanical properties (conventional yield strength, tensile strength, elongation, proportional elongation and contraction) after annealing at different temperatures for 1 hour. Thermal stability of the same grade of material has been found to be different for different batches and to depend on the structural conditions of deformed material. The zone of thermal stability for copper of the two grades of interest does not depend on the material’s chemical composition.

A Study on the Effect of the Temperature on Mechanical Properties of H90 Copper Strip

2019 ◽  
Vol 950 ◽  
pp. 65-69
Author(s):  
Sun Fei ◽  
Xu Cheng
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Elastic Modulus ◽  
Yield Strength ◽  
Effect Of Temperature ◽  
Basic Material ◽  
Copper Strip ◽  
Study Results ◽  
Different Temperatures ◽  
Strip Test

In order to study the effect of temperature on the mechanical properties of H90 copper strip material, the H90 copper strip test pieces were heated to different temperatures (20~600 °C) for tensile test; the yield strength, tensile strength, elastic modulus and elongation of H90 copper strip at different temperatures were obtained. Based on the test results, the empirical models of yield strength, tensile strength, elastic modulus of H90 copper strip at high temperature were established; the test showed that, with the increase of temperature, the yield strength, tensile strength and elastic modulus of H90 copper strip decreased greatly, and the elongation after fracture first increased-decreased-increased at 20~600 °C. The study results in this paper provide basic material data for analyzing the effect of temperature on the continuous firing of firearms and other weapons.

scholarly journals Dynamic Constitutive Model of Ultra-High Molecular Weight Polyethylene (UHMWPE): Considering the Temperature and Strain Rate Effects

Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1561 ◽  
Author(s):  
Kebin Zhang ◽  
Wenbin Li ◽  
Yu Zheng ◽  
Wenjin Yao ◽  
Changfang Zhao
Keyword(s):  
Mechanical Properties ◽  
Constitutive Model ◽  
Strain Rate ◽  
Split Hopkinson Pressure Bar ◽  
Plastic Material ◽  
Strain Rates ◽  
Hopkinson Pressure Bar ◽  
Ballistic Performance ◽  
Stress Strain ◽  
Different Temperatures

The temperature and strain rate significantly affect the ballistic performance of UHMWPE, but the deformation of UHMWPE under thermo-mechanical coupling has been rarely studied. To investigate the influences of the temperature and the strain rate on the mechanical properties of UHMWPE, a Split Hopkinson Pressure Bar (SHPB) apparatus was used to conduct uniaxial compression experiments on UHMWPE. The stress–strain curves of UHMWPE were obtained at temperatures of 20–100 °C and strain rates of 1300–4300 s−1. Based on the experimental results, the UHMWPE belongs to viscoelastic–plastic material, and a hardening effect occurs once UHMWPE enters the plastic zone. By comparing the stress–strain curves at different temperatures and strain rates, it was found that UHMWPE exhibits strain rate strengthening and temperature softening effects. By modifying the Sherwood–Frost model, a constitutive model was established to describe the dynamic mechanical properties of UHMWPE at different temperatures. The results calculated using the constitutive model were in good agreement with the experimental data. This study provides a reference for the design of UHMWPE as a ballistic-resistant material.

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.

Dynamic Constitutive Relation of EMC

2010 ◽  
Vol 129-131 ◽  
pp. 988-992
Author(s):  
Bo Wang ◽  
Tong Chen ◽  
Xue Feng Shu
Keyword(s):  
Yield Strength ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Properties ◽  
Strain Rates ◽  
Hopkinson Pressure Bar ◽  
Static Tests ◽  
Good Accordance ◽  
Different Temperatures ◽  
Split Hopkinson ◽  
Pressure Bar

In this paper, dynamic properties of EMC were studied at different temperatures and different strain rates. Firstly EMC was investigated by quasi-static tests. Secondly a series of dynamic compressive experiments of EMC were conducted using the Split Hopkinson Pressure Bar (SHPB) at sectional height of strain rates. Thirdly EMC constants in ZWT model were determined from experiments. Corresponding measurements were conducted at temperatures ranging from 20°C to 160°C. The results indicate that the yield strength and flow stress of EMC increase remarkably with the increase of strain rate and it is shows that the assembled curve is fit good accordance with actual the experimental curve. However, the yield strength of EMC is a little change with the increase of temperature which is ranging from 20°C to 160°C.

scholarly journals Mechanical Properties of Antarctic Deep-Core Ice

1979 ◽  
Vol 24 (90) ◽  
pp. 487-489 ◽  
Author(s):  
H. Shoji ◽  
A. Higashi
Keyword(s):  
Mechanical Properties ◽  
Ice Sheet ◽  
Vertical Direction ◽  
Tensile Tests ◽  
Strain Rates ◽  
Stress Strain ◽  
The Core ◽  
Different Temperatures

AbstractTensile tests were carried out with core-ice samples obtained from various depths at Byrd Station, Antarctica in 1968, Specimens for the tests were so prepared as to have their long axes parallel (L specimen), perpendicular (T specimen), and inclined at 450(I specimen) with respect to the axis of the core, or to the vertical direction of the ice sheet. Stress-strain relations for many specimens were obtained from tensile tests with different strain-rates and also at different temperatures between —10 and — 20°C.

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.

Microstructure and Mechanical Properties of 45 Steel by Zero Time Holding Quenching

2011 ◽  
Vol 335-336 ◽  
pp. 577-582
Author(s):  
Xiao Wen Chen ◽  
De Fen Zhang ◽  
Guang Wen Long ◽  
Qin Zou ◽  
Li Wang
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
High Temperature ◽  
Yield Strength ◽  
Quenching Temperature ◽  
Universal Testing ◽  
Quenching Condition ◽  
Steel Increase ◽  
Different Temperatures ◽  
Zero Time

45 steel was quenched with zero time holding at different temperatures, followed by a high temperature tempering. The influence of quenching temperature on hardness, yield strength, tensile strength and microstructure of the steels was investigated by Rockwell tester, universal testing machines and metallographic microscopy, respectively. The results show that under quenching condition of zero time holding, hardness and strength of the 45 steel increase with increasing quenching temperature and reach the maximum at 860 °C, where the content of martensite is maximum while that of ferrite is minimum in the specimen. At higher temperatures, the grains become obviously coarse, resulting in decrease of mechanical properties.

Radiation Hardening and Plastic Instability in Neutron Irradiated CuCrZr

2001 ◽  
Vol 683 ◽  
Author(s):  
Dan. J. Edwards ◽  
Bachu. N. Singh
Keyword(s):  
Mechanical Properties ◽  
Yield Strength ◽  
Yield Stress ◽  
Yield Point ◽  
Work Hardening ◽  
Plastic Instability ◽  
Tensile Behavior ◽  
Radiation Hardening ◽  
Post Irradiation ◽  
Microstructure And Mechanical Properties

ABSTRACTThe effect of post-irradiation annealing at 300°C for 50 hours on the microstructure and mechanical properties of CuCrZr irradiated to 0.3 dpa at 100°C has been evaluated. The post- irradiation annealing restores some ductility and work hardening to the material as well as lowers the yield strength, however it does not completely remove the effects of irradiation. A comparison of the microstructural features and mechanical properties in the as-irradiated condition and in the post-irradiation annealed case highlights the fact that the observed microstructure does not necessarily correlate with the changes in tensile behavior, most notably in the removal of the yield point and lowering of the yield stress after annealing.

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