Plastic Deformation of Thin Films – Bending

2001 ◽  
Vol 695 ◽  
Author(s):  
T. Nozaki ◽  
Y. Kogure ◽  
Masao Doyama
Keyword(s):  
Thin Films ◽  
Molecular Dynamics ◽  
Plastic Deformation ◽  
Single Crystal ◽  
Atomic Potential ◽  
Shockley Partial ◽  
Partial Dislocations ◽  
Extended Surface ◽  
Edge Dislocations

ABSTRACTWidely accepted model of bending of a single crystal suggests that edge dislocations are introduced from both the compressed surface and extended surface. The present study examined this model by molecular dynamics using an embedded potential. Shockley partial dislocations are created on the compressed surface. Due to the characteristics of inter atomic potential, the stress on the compression surface is higher than that on the extended surface.

Computer Simulation of Bending Plastic Deformation and Creation of Dislocations in Copper Thin Films

1994 ◽  
Vol 367 ◽  
Author(s):  
H. Tsukahara ◽  
Y. Niwa ◽  
T. Takayama ◽  
Masao Doyama
Keyword(s):  
Thin Films ◽  
Molecular Dynamics ◽  
Computer Simulation ◽  
Plastic Deformation ◽  
Single Crystal ◽  
Slip Plane ◽  
Molecular Dynamics Method ◽  
Copper Single Crystal ◽  
Small Single Crystal ◽  
Dynamics Method

AbstractA small single crystal of copper with a notch has been bent by use of the molecular dynamics method. The bend axis was [110]. Dislocations were created near the tip of the notch and moved on (111) slip plane. Pulling a copper single crystal, half dislocations were created in such a way that the bending was compensated.

Creation of Dislocations in a Shall Copper Single Crystal

1992 ◽  
Vol 278 ◽  
Author(s):  
Masao Doyama
Keyword(s):  
Single Crystal ◽  
Yield Stress ◽  
Partial Dislocation ◽  
Stacking Fault ◽  
Copper Single Crystal ◽  
Shockley Partial ◽  
Partial Dislocations ◽  
Edge Dislocations

AbstractEdge dislocations were created on a surface of a small copper single crystal. Very sharp yield stress was observed when a partial dislocation was created. Edge dislocations in copper were split into Heidenreich–Shockley partial dislocations connected with the stacking fault.

An investigation of nanoindentation tests on the single crystal copper thin film via an atomic force microscope and molecular dynamics simulation

2007 ◽  
Vol 221 (2) ◽  
pp. 259-266 ◽  
Author(s):  
D Huo ◽  
Y Liang ◽  
K Cheng
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Plastic Deformation ◽  
Size Effect ◽  
Single Crystal ◽  
Atomic Force Microscope ◽  
Md Simulations ◽  
Single Crystal Copper ◽  
Atomic Force

Nanoindentation tests performed in an atomic force microscope have been utilized to directly measure the mechanical properties of single crystal metal thin films fabricated by the vacuum vapour deposition technique. Nanoindentation tests were conducted at various indentation depths to study the effect of indentation depths on the mechanical properties of thin films. The results were interpreted by using the Oliver-Pharr method with which direct observation and measurement of the contact area are not required. The elastic modulus of the single crystal copper film at various indentation depths was determined as 67.0 > 6.9 GPa on average, which is in reasonable agreement with the results reported by others. The indentation hardness constantly increases with decreasing indentation depth, indicating a strong size effect. In addition to the experimental work, a three-dimensional nanoindentation model of molecular dynamics (MD) simulations with embedded atom method (EAM) potential is proposed to elucidate the mechanics and mechanisms of nanoindentation of thin films from the atomistic point of view. MD simulations results show that due to the size effect no distinct dislocations were observed in the plastic deformation processes of the single crystal copper thin films, which is significantly different from the plastic deformation mechanism in bulk materials.

Effects of temperature and FCC phase size on the deformation mechanism of pure titanium nanopillars: A molecular dynamics simulation

2021 ◽  
pp. 2150253
Author(s):  
Dan Yang ◽  
Junqiang Ren ◽  
Qi Wang ◽  
Xuefeng Lu ◽  
Qingfeng Lei ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Plastic Deformation ◽  
Deformation Mechanism ◽  
Compressive Loading ◽  
Tensile Loading ◽  
Dynamics Simulation ◽  
Shockley Partial ◽  
Partial Dislocations ◽  
Phase Size ◽  
Fcc Phase

The mechanism of plastic deformation under tensile and compressive loading of hexagonal close-packed (HCP)/face-centered cubic (FCC) biphasic titanium (Ti) nanopillars at different temperatures (70 K, 150 K, 300 K and 400 K) and different FCC phase sizes (2 nm, 4 nm, 6 nm and 8 nm) was investigated by molecular dynamics (MD). The plastic deformation is mainly concentrated in the FCC phase during compression loading. The HCP/FCC interface is the main source of [Formula: see text] Shockley partial dislocations. As the temperature increases, the dislocation nucleation rate increases and the surface dislocation source is activated. During tensile loading, it is more likely that the Shockley partial dislocations react with each other in the FCC phase to form Lomer–Cottrell sessile dislocations and stacking fault (SF) nets. When the temperature is reduced to 70 K, tensile twins are formed at the phase interface. The plastic deformation is dominated by twins and [Formula: see text] dislocation slip occurs in the HCP phase. The effect of the FCC phase size on the plastic deformation mechanism of the nanopillar is strong. The FCC phase is transformed into the HCP phase when the FCC phase size in the nanopillar is reduced to 4 nm under compressive loading. However, twin deformation occurs at the HCP/FCC interface when the FCC phase size is reduced to 2 nm under tensile loading.

scholarly journals Molecular Dynamics Simulation of Crack Propagation in Single-Crystal Aluminum Plate with Central Cracks

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Jun Ding ◽  
Lu-sheng Wang ◽  
Kun Song ◽  
Bo Liu ◽  
Xia Huang
Keyword(s):  
Molecular Dynamics ◽  
Plastic Deformation ◽  
Crack Propagation ◽  
Strain Rate ◽  
Single Crystal ◽  
Crack Length ◽  
Crack Growth ◽  
Plastic Yield ◽  
Model Size ◽  
Dislocation Multiplication

The crack propagation process in single-crystal aluminum plate (SCAP) with central cracks under tensile load was simulated by molecular dynamics method. Further, the effects of model size, crack length, temperature, and strain rate on strength of SCAP and crack growth were comprehensively investigated. The results showed that, with the increase of the model size, crack length, and strain rate, the plastic yield point of SCAP occurred in advance, the limit stress of plastic yield decreased, and the plastic deformability of material increased, but the temperature had less effect and sensitivity on the strength and crack propagation of SCAP. The model size affected the plastic deformation and crack growth of the material. Specifically, at small scale, the plastic deformation and crack propagation in SCAP are mainly affected through dislocation multiplication and slip. However, the plastic deformation and crack propagation are obviously affected by dislocation multiplication and twinning in larger scale.

Void and Dislocation Microstructure Development in Heteroepitaxial Film Growth

1995 ◽  
Vol 399 ◽  
Author(s):  
Richard W. Smith ◽  
David J. Srolovitz
Keyword(s):  
Thin Films ◽  
Molecular Dynamics ◽  
Film Growth ◽  
Lattice Misfit ◽  
Two Dimensional ◽  
Microstructure Development ◽  
Non Equilibrium Molecular Dynamics ◽  
Dynamics Simulations ◽  
Film Substrate ◽  
Edge Dislocations

ABSTRACTTwo dimensional, non-equilibrium molecular dynamics simulations have been performed to examine the microstructures of both homoepitaxial and heteroepitaxial thin films grown on single crystal substrates. The principal microstructural features to develop within these films are small voids and edge dislocations. Voids form near the surface of the growing film as surface depressions between microcolumns pinch off to become closed volumes. These voids often form in such a way as to introduce dislocations into the crystal with their cores positioned within the voids. Dislocations are also formed during heteroepitaxy at the interface between the substrate and film. These dislocations tend to be mobile. When voids are present in the film and when the lattice misfit is low, dislocations tend to be trapped in the voids or pulled toward them due to dislocation image interactions. Once attached to voids, dislocations are effectively pinned there. When voids are absent or when the misfit is high, dislocations are restricted to the film-substrate interface. In the case of heteroepitaxy, dislocations are found to relieve either tensile or compressive misfit stresses. Misfit stresses may also be accommodated, to some extent, merely by the free volume of the voids themselves.

Molecular Dynamics Simulation on the Out-of Plane Thermal Conductivity of Single-Crystal Carbon Thin Films

2009 ◽  
Vol 60-61 ◽  
pp. 430-434 ◽  
Author(s):  
Xing Li Zhang ◽  
Zhao Wei Sun ◽  
Guo Qiang Wu
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Potential Energy ◽  
Film Thickness ◽  
Single Crystal ◽  
Diamond Crystal ◽  
Dynamics Simulation ◽  
Crystal Direction

In this article, we select corresponding Tersoff potential energy to build potential energy model and investigate the thermal conductivities of single-crystal carbon thin-film. The equilibrium molecular dynamics (EMD) method is used to calculate the nanometer thin film thermal conductivity of diamond crystal at crystal direction (001), and the non-equilibrium molecular dynamics (NEMD) is used to calculate the nanometer thin film thermal conductivity of diamond crystal at crystal direction (111). The results of calculations demonstrate that the nanometer thin film thermal conductivity of diamond crystal is remarkably lower than the corresponding bulk experimental data and increase with increasing the film thickness, and the nanometer thin film thermal conductivity of diamond crystal relates to film thickness linearly in the simulative range. The nanometer thin film thermal conductivity also demonstrates certain regularity with the change of temperature. This work shows that molecular dynamics, applied under the correct conditions, is a viable tool for calculating the thermal conductivity of nanometer thin films.

scholarly journals Mechanical Properties of 3C-SiC Films for MEMS Applications

2007 ◽  
Vol 1049 ◽  
Author(s):  
Jayadeep Deva Reddy ◽  
Alex A. Volinsky ◽  
Christopher L. Frewin ◽  
Chris Locke ◽  
Stephen E. Saddow
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
Silicon Carbide ◽  
Plastic Deformation ◽  
Elastic Modulus ◽  
Single Crystal ◽  
Elastic Contact ◽  
Si Substrates ◽  
Sic Films

AbstractThere is a technological need for hard thin films with high elastic modulus and fracture toughness. Silicon carbide (SiC) fulfills such requirements for a variety of applications at high temperatures and for high-wear MEMS. A detailed study of the mechanical properties of single crystal and polycrystalline 3C-SiC films grown on Si substrates was performed by means of nanoindentation using a Berkovich diamond tip. The thickness of both the single and polycrystalline SiC films was around 1-2 μm. Under indentation loads below 500 μN both films exhibit Hertzian elastic contact without plastic deformation. The polycrystalline SiC films have an elastic modulus of 457 GPa and hardness of 33.5 GPa, while the single crystalline SiC films elastic modulus and hardness were measured to be 433 GPa and 31.2 GPa, respectively. These results indicate that polycrystalline SiC thin films are more attractive for MEMS applications when compared with the single crystal 3C-SiC, which is promising since growing single crystal 3C-SiC films is more challenging.

Sign in / Sign up

Export Citation Format

Share Document