Effects of Strain Rate on the Tensile Deformation of Single-Crystal Copper Films

2011 ◽  
Vol 675-677 ◽  
pp. 671-673 ◽  
Author(s):  
Shuang Xu ◽  
Ya Fang Guo
Keyword(s):  
Strain Rate ◽  
Single Crystal ◽  
Tensile Deformation ◽  
Md Simulations ◽  
Copper Films ◽  
Strain Rate Effects ◽  
Single Crystal Copper ◽  
Cu Films ◽  
Rate Effects ◽  
Eam Potential

Molecular dynamics (MD) simulations with an EAM potential are carried out to study the strain rate effects on the tensile deformation of single-crystal copper films. The stress, the atomic energy, as well as the atomic configurations of the systems are presented to explore the strain rate effects on copper films. It is found that yield stress increases with loading rate. Meanwhile, deformation mechanisms with different strain rates are analyzed in the present work. At lower strain rate, slips along {111} planes are primarily responsible for the plastic deformation in nano-Cu films. As strain rate increased, the motion of dislocations becomes easier, a transition of the deformation mechanism from sequential propagation of slips along well-defined slip planes to complex cross-slip.

Development of Multi-Scale Computation Framework to Investigate the Failure Behavior of the Materials

2008 ◽  
Vol 33-37 ◽  
pp. 875-880
Author(s):  
Zhuo Zhuang ◽  
Zhan Li Liu ◽  
Xiao Chuan You ◽  
Y. Guo
Keyword(s):  
Strain Rate ◽  
Single Crystal ◽  
Yield Stress ◽  
Md Simulations ◽  
Shear Instability ◽  
Copper Block ◽  
Strain Rate Effects ◽  
Single Crystal Copper ◽  
Fcc Metals ◽  
Rate Effects

With the development of material science, especially as MEMS/NEMS are playing a more and more important role in modern engineering, some mechanical behaviors of materials, e.g., fracture, shear instability, need to be investigated from multidisciplinary perspective. The molecular dynamics (MD) simulations are performed on single-crystal copper block under simple shear to investigate the size and strain rate effects on the mechanical responses of face-centered cubic (fcc) metals. It is shown that the yield stress decreases with the specimen size and increases with the strain rate. Based on the theory of dislocation nucleation, a modified power law is proposed to predict the scaling behavior of fcc metals. In the MD simulations with different strain rates, a critical strain rate exists for each single-crystal copper block of given size, below which the yield stress is nearly insensitive to the strain rate. A hyper-surface is therefore formulated to describe the combined size and strain rate effects on the plastic yield stress of fcc metals.

Response of copper nanowires in dynamic tensile deformation

2004 ◽  
Vol 218 (6) ◽  
pp. 599-606 ◽  
Author(s):  
W Liang ◽  
M Zhou
Keyword(s):  
Strain Rate ◽  
Cross Sections ◽  
Tensile Deformation ◽  
Md Simulations ◽  
Dislocation Motion ◽  
Specimen Size ◽  
Copper Nanowires ◽  
Strain Rate Effects ◽  
Embedded Atom ◽  
Eam Potential

Molecular dynamics (MD) simulations with an embedded atom method (EAM) potential are carried out to analyse the size and strain rate effects in the tensile deformation of single-crystal copper nanowires. The cross-sections of the wires are squares with dimensions of between 5 and 20 lattice constants (or 1.8-7.2nm). Deformations under constant strain rates between 1.67 × 107 and 1.67 × 1010s−1 are analysed. It is found that the yield stress decreases with specimen size and increases with loading rate. On the other hand, ductility increases with specimen size and strain rate. The influence of specimen size is due to enhanced opportunities for dislocation motion at larger sizes. The influence of strain rate is due to the dynamic wave effect or phonon drag which impedes the motion of dislocations. The analysis also focuses on the variation in deformation mechanisms with specimen size and strain rate. Slip along alternating (111) planes is observed in small wires, while multiple cross-slips are primarily responsible for the progression of plastic deformation in larger wires. As strain rate is increased, a transition of the deformation mechanism from sequential propagation of slip along well-defined and favourably oriented slip planes to cross-slip, and then to amorphization, is observed.

Temperature and Strain Rate Effects on Plastic Deformation of Titanium Alloys

2007 ◽  
Vol 539-543 ◽  
pp. 3619-3624 ◽  
Author(s):  
K. Ogawa
Keyword(s):  
Titanium Alloy ◽  
Strain Rate ◽  
Titanium Alloys ◽  
Tensile Deformation ◽  
Beta Titanium Alloy ◽  
Stress Strain ◽  
Strain Rate Effects ◽  
Wide Range ◽  
Rate Effects ◽  
The Impact

Since titanium alloys are the most promising structural materials for the high velocity vehicles, the impact tensile strength of the materials is presently investigated. Three kinds of aging treatments on the beta-titanium alloy were performed, and the tensile deformation behaviors were identified in the wide range of the temperature and the strain rate. The stress－strain relations of the titanium alloy significantly depend on the temperature and the strain rate investigated. Thermally activated process concept was applied to explain the experimental results, and the stress-strain relations at high strain rates were well understood with taking account of adiabatic heating effect. It has been found that the stress-strain curves depend on the microstructures, while the temperature and the strain rate effects are almost independent of the different aging treatments.

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