The Role Played By Two Parallel Free Surfaces In The Deformation Mechanism Of Nano-crystalline Metals: A Molecular Dynamics Simulation

2000 ◽  
Vol 634 ◽  
Author(s):  
P. M. Derlet ◽  
H. Van Swygenhoven
Keyword(s):  
Molecular Dynamics ◽  
Deformation Mechanism ◽  
Deformation Behaviour ◽  
Small Distance ◽  
Dynamics Simulation ◽  
Intrinsic Properties ◽  
Free Surfaces ◽  
Grain Sizes ◽  
Nano Crystalline

ABSTRACTFormer molecular dynamics computer simulations of polycrystalline Ni and Cu metals with mean grain sizes ranging between 3 and 12 nm demonstrated a change in deformation mechanism as a function of grain size: at the smallest grain sizes all deformation is accommodated in the grain boundaries. In this paper we report on the influence of the presence of two free surfaces on the deformation behaviour. The purpose of this simulation is to study which phenomena observed in in-situ tensile experiments performed in the electron microscope can be expected to be intrinsic properties of the deformation process and which phenomena are due to the presence of two free surfaces separated by a very small distance.

Molecular dynamics simulation and in-situ MRI observation of organic exclusion during CO2 hydrate growth

2021 ◽  
Vol 764 ◽  
pp. 138287
Author(s):  
Lunxiang Zhang ◽  
Lingjie Sun ◽  
Yi Lu ◽  
Yangmin Kuang ◽  
Zheng Ling ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Dynamics Simulation

Molecular dynamics simulation of grain size effect on friction and wear of nanocrystalline zirconium

2020 ◽  
pp. 135065012094507
Author(s):  
Kehao Zhu ◽  
Xiaoyu Zhang ◽  
Xinlu Yuan ◽  
Gen Li ◽  
Pingdi Ren
Keyword(s):  
Molecular Dynamics ◽  
Grain Size ◽  
Molecular Dynamics Simulation ◽  
Friction And Wear ◽  
Atomic Displacement ◽  
Dynamics Simulation ◽  
Friction Forces ◽  
Grain Sizes ◽  
Crystalline Substrate ◽  
Boundary Rotation

In this study, molecular dynamics simulation was conducted to investigate the frictional behaviors between diamond tool and zirconium (Zr) substrates at the nanoscale. The effects of grain size on friction and wear were discussed under different sliding velocities. The simulation results showed that the friction forces had similar variation tendencies under different sliding velocities. Besides, the friction responses were stronger at high sliding velocities because of the atomic adhesion while the ploughing effect was more obvious at slower sliding velocity. Moreover, both the friction forces and the wear amounts increased with the decrease in the average grain sizes of the substrates. To explain this phenomenon, the internal mechanism was investigated by using the dislocation extract algorithm and the atomic displacement analyses. The results showed that the [0001]-oriented single crystalline substrate was prone to form continuous dislocation structures moving tangentially along the sliding direction due to the characteristic of Zr's slip systems, whereas grain boundaries conducted the deformation further into the polycrystalline substrates, increasing the contact areas and causing atomic accumulation in front, both resulted in stronger friction responses and wear. Accordingly, with the decrease in average grain sizes, the substrates experienced more severe subsurface damage and the deformation mechanism of nanocrystalline Zr had evolved from dislocation emission to grain boundary rotation and sliding.

Molecular dynamics simulation studies on the plastic behaviors of an iron nanowire under torsion

RSC Advances ◽  
2016 ◽  
Vol 6 (34) ◽  
pp. 28792-28800 ◽  
Author(s):  
Chong Qiao ◽  
Yanli Zhou ◽  
Xiaolin Cai ◽  
Weiyang Yu ◽  
Bingjie Du ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Plastic Deformation ◽  
Molecular Dynamics Simulation ◽  
Deformation Mechanism ◽  
Driving Force ◽  
Dynamics Simulation ◽  
Simulation Studies ◽  
Plastic Deformation Mechanism ◽  
Constant Torsion ◽  
External Driving

The plastic deformation mechanism of iron (Fe) nanowires under torsion is studied using the molecular dynamics (MD) method by applying an external driving force at a constant torsion speed.

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