INFLUENCE OF PRESSURE AND ATOMIC CONCENTRATION ON STRUCTURE AND MECHANICAL PROPERTIES OF CuNi ALLOY BY MOLECULAR DYNAMICS SIMULATION

2020 ◽  
Vol 65 (6) ◽  
pp. 54-60
Author(s):  
Thao Nguyen Thi ◽  
Hang Trinh Thi Thu
Keyword(s):  
Mechanical Properties ◽  
Dynamics Simulation ◽  
Embedded Atom Method ◽  
Face Centered Cubic ◽  
Atomic Concentration ◽  
Common Neighbor ◽  
Hexagonal Close Packed ◽  
Embedded Atom ◽  
The Common ◽  
Face Centered

The structure and mechanical properties of Cu80Ni20 and Cu50Ni50 alloys with the size of 4000 atoms have been investigated using molecular dynamic (MD) simulation. The interactions between atoms of the system were calculated by the Sutton-Chen type of embedded atom method. Using a cooling rate of 0.01 K\ps, we find that both Ni and Cu atoms are crystallized into face centered cubic (fcc) and the hexagonal close packed (hcp) phases when the sample was cooled down to 300 K. The atomic concentration of CuNi alloy samples have a different effect on this crystallization. The transformation to the crystalline phase is analyzed through the Common Neighbor Analysis (CNA) methods. Furthermore, we focus on the dependence of the mechanical properties of CuNi alloy on pressure and atomic concentration

Molecular Dynamics Simulation of the Solidification of Liquid Nickel Nanowires

2007 ◽  
Vol 121-123 ◽  
pp. 1053-1056
Author(s):  
Guo Rong Zhong ◽  
Qiu Ming Gao
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Dynamics Simulation ◽  
Face Centered Cubic ◽  
Liquid Nickel ◽  
Cooling Rates ◽  
Final Structure ◽  
Embedded Atom ◽  
Nickel Nanowires ◽  
Face Centered

Molecular dynamics simulation of the solidification behavior of liquid nickel nanowires has been carried out based on the embedded atom potential with different cooling rates. The nanowires constructed with a face-centered cubic structure and a one-dimensional (1D) periodical boundary condition along the wire axis direction. It is found that the final structure of Ni nanowires strongly depend on the cooling rates during solidification from liquid. With decreasing cooling rates the final structure of the nanowires varies from amorphous to crystalline via helical multi-shelled structure.

Mechanical stability and strength of a single Au crystal

2008 ◽  
Vol 86 (7) ◽  
pp. 935-941 ◽  
Author(s):  
J -M Zhang ◽  
Y Yang ◽  
K -W Xu ◽  
V Ji
Keyword(s):  
Mechanical Stability ◽  
Energy Difference ◽  
Theoretical Strength ◽  
Stable Region ◽  
Embedded Atom Method ◽  
Face Centered Cubic ◽  
Embedded Atom ◽  
Free Body ◽  
Face Centered ◽  
Bcc Phase

The structural stability and theoretical strength of a Au face-centered cubic (FCC) crystal under uniaxial loading is investigated by combining the modified analytical embedded atom method (MAEAM) with Born stability criteria. The results show that under sufficient compression, there exists a stress-free body-centered cubic (BCC) phase, which is unstable and slips spontaneously to a stress-free metastable body-centered tetragonal phase by consuming internal energy. The structural energy difference between the BCC and FCC phases is in good agreement with the experimental value. The stable region ranged from –2.21 GPa to 6.31 GPa in the theoretical strength or from –9.83% to 7.87% in the strain correspondingly.PACS Nos.: 62.20.–x, 61.50.Ks, 81.05.Bx

Molecular Dynamics Simulation of Compressive Mechanical Behavior of Nanocrystalline Fe

2005 ◽  
Vol 475-479 ◽  
pp. 3291-3294
Author(s):  
Shi Fang Xiao ◽  
Yu Hu Wang
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Plastic Deformation ◽  
Deformation Process ◽  
Dynamics Simulation ◽  
Embedded Atom Method ◽  
Deformation Region ◽  
Embedded Atom ◽  
Boundary Atom ◽  
Strain Strengthening

The uniaxial compressive mechanical properties of nanocrystalline Fe are simulated with a molecular dynamics technique and the analytical embedded-atom method. An asymmetrical mechanical phenomenon between tensile and compressive process is found, and the yield stress and flow stress in compression are higher than those in tension simulations. The compressive deformation process can be described as three characteristic regions: quasi-elastic deformation, plastic flowing deformation, and strain strengthening. During the plastic flowing deformation region, the material shows very good compressive ductibility. The plastic deformation is mainly dominated by the grain boundary atom slide.

Atomistic Study of the Mechanical Properties of One-Dimensional Nanomaterials

2005 ◽  
Vol 901 ◽  
Author(s):  
Kazuhito Shintani ◽  
Shunji Kameoka ◽  
Shuhei Sato ◽  
Yusuke Kometani
Keyword(s):  
Mechanical Properties ◽  
Cross Sections ◽  
Dynamics Simulation ◽  
Embedded Atom Method ◽  
One Dimensional ◽  
Embedded Atom ◽  
Young’S Moduli ◽  
Modified Embedded Atom Method ◽  
Au Nanowires ◽  
Atomistic Study

AbstractThe mechanical properties of Au nanowires under a uniaxial load are investigated by molecular-dynamics simulation. The modified embedded-atom method (MEAM) potential is employed to calculate the interactions between Au atoms. Ten kinds of model nanowires with different cross-sections and axis directions are prepaired. The structural dependence and size effect of the Young’s moduli of Au nanowires are discussed.

scholarly journals Effect of Different Post-Sintering Temperatures on the Microstructures and Mechanical Properties of a Pre-Sintered Co–Cr Alloy

Metals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1036 ◽  
Author(s):  
Seong-Ho Jang ◽  
Bong Min ◽  
Min-Ho Hong ◽  
Tae-Yub Kwon
Keyword(s):  
Mechanical Properties ◽  
Cubic Phase ◽  
Carbide Formation ◽  
Face Centered Cubic ◽  
Cobalt Chromium ◽  
Hexagonal Close Packed ◽  
Soft Metal ◽  
Face Centered ◽  
Few Data ◽  
Sintered State

Although a cobalt–chromium (Co–Cr) blank in a pre-sintered state has been developed, there are few data on the optimal temperature for the alloy in terms of the desired mechanical properties. A metal block (Soft Metal, LHK, Chilgok, Korea) was milled to produce either disc-shaped or dumbbell-shaped specimens. All the milled specimens were post-sintered in a furnace at 1250, 1350 or 1450 °C. The microstructures, shrinkage and density of the three different alloys were investigated using the disc-shaped specimens. The mechanical properties were investigated with a tensile test according to ISO 22674 (n = 6). The number and size of the pores in the alloys decreased with increased temperature. The shrinkage and density of the alloys increased with temperature. In the 1250 °C alloy, the formation of the ε (hexagonal close-packed) phase was more predominant than that of the γ (face-centered cubic) phase. The 1350 °C and 1450 °C alloys showed γ phase formation more predominantly. Carbide formation was increased along with temperature. The 1450 °C group showed the largest grain size among the three groups. In general, the 1350 °C group exhibited mechanical properties superior to the 1250 °C and 1450 °C groups. These findings suggest that 1350 °C was the most optimal post-sintering temperature for the pre-sintered blank.

Deformation Mechanisms of Nanocrystalline Hexagonal Close-Packed Metals

2006 ◽  
Vol 924 ◽  
Author(s):  
Guangping Zheng
Keyword(s):  
Deformation Twinning ◽  
Dynamics Simulation ◽  
Deformation Mechanisms ◽  
Face Centered Cubic ◽  
Transformation Mechanism ◽  
Shockley Partial Dislocation ◽  
Hexagonal Close Packed ◽  
Simulation Results ◽  
Face Centered ◽  
Fcc Structure

ABSTRACTUsing molecular dynamics simulation of nanocrystalline (nc) samples with grain size of 10 nm, a reverse martensitic transformation from hexagonal close-packed (hcp) to face-centered cubic (fcc) structure is observed in nc-cobalt and nc-zirconium undergoing plastic deformation. In nc-cobalt hcp-to-fcc transformation is prevalent and deformation twinning is rarely observed. The transformation mechanism involves the motion of Shockley partial dislocation 1/3<1100> in every other (0001)hcp /(111)fcc plane. In nc-zirconium the hcp-to-fcc transformation competes with the deformation twinning. From the simulation results, it is suggested that the interaction among partials should be considered to understand the deformation mechanisms of hcp nc metals.

scholarly journals The Effect of Y/Er and Zn Addition on the Microstructure and Mechanical Properties of Mg-11Li Alloy

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3066 ◽  
Author(s):  
Mingquan Zhang ◽  
Jinghuai Zhang ◽  
Ruizhi Wu ◽  
Hongwei Cui ◽  
Ertuan Zhao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fine Particles ◽  
Cast Alloy ◽  
Intermetallic Phase ◽  
Intermetallic Phases ◽  
Face Centered Cubic ◽  
Hexagonal Close Packed ◽  
Intermetallic Particles ◽  
Zn Addition ◽  
Face Centered

Although body-centered cubic (BCC) structural magnesium–lithium (Mg-Li) alloys have lower density and better formability than common hexagonal close-packed (HCP) Mg alloys, their applications remain limited due to their low strength. The purpose of this study is to investigate the effect of Y/Er and Zn addition on the microstructure and tensile properties of Mg-11Li alloy with a BCC structural matrix by comparing Mg-11Li, Mg-11Li-4Y-2Er-2Zn, and Mg-11Li-8Y-4Er-4Zn (wt %) alloys. The results indicate that the addition of Y/Er and Zn at a ratio of 3:1 cannot promote the formation of long-period stacking ordered structure in Mg-11Li alloy such as that in Mg-Y-Er-Zn alloys and the dominant intermetallic phases formed are BCC Mg24RE5 and face-centered cubic (FCC) Mg3RE2Zn3 phases. With an increase of the content of Y/Er and Zn in an as-cast alloy, the fraction of intermetallic particles increases and the grain size decreases. The addition of Y/Er, as well as Zn, dramatically promotes the refinement of dynamic recrystallization (DRX) during extrusion. The initial intermetallic phases induced by Y/Er and Zn addition are broken into relatively fine particles during extrusion, and this contributes to refining the dynamic recrystallized (DRXed) grains mainly by the particle stimulated nucleation mechanism. The as-extruded Mg-11Li-4Y-2Er-2Zn and Mg-11Li-8Y-4Er-4Zn alloys exhibit much higher tensile strength as compared with as-extruded Mg-11Li alloy, which is mainly ascribed to the refined DRXed grains and numerous dispersed intermetallic phase particles. It is suggested that further refinement of intermetallic particles in these extruded Mg-11Li-based alloys may lead to higher quality alloy materials with low density and excellent mechanical properties.

scholarly journals Crystallization of FCC and BCC Liquid Metals Studied by Molecular Dynamics Simulation

Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1532
Author(s):  
Dmitri V. Louzguine-Luzgin ◽  
Andrey I. Bazlov
Keyword(s):  
Molecular Dynamics ◽  
Structural Changes ◽  
Liquid Metals ◽  
Crystal Nucleation ◽  
Dynamics Simulation ◽  
Face Centered Cubic ◽  
Common Neighbor ◽  
Embedded Atom ◽  
Structure Observation ◽  
Embedded Atom Method Potential

The atomic structure variations on cooling, vitrification and crystallization processes in liquid metals face centered cubic (FCC) Cu are simulated in the present work in comparison with body centered cubic (BCC) Fe. The process is done on continuous cooling and isothermal annealing using a classical molecular-dynamics computer simulation procedure with an embedded-atom method potential at constant pressure. The structural changes are monitored with direct structure observation in the simulation cells containing from about 100 k to 1 M atoms. The crystallization process is analyzed under isothermal conditions by monitoring density and energy variation as a function of time. A common-neighbor cluster analysis is performed. The results of thermodynamic calculations on estimating the energy barrier for crystal nucleation and a critical nucleus size are compared with those obtained from simulation. The differences in crystallization of an FCC and a BCC metal are discussed.

Molecular Dynamics Study on Interaction between Voids for Pure Aluminum

2010 ◽  
Vol 452-453 ◽  
pp. 845-848
Author(s):  
Shu Sheng Xu ◽  
Xiang Guo Zeng ◽  
Hua Yan Chen
Keyword(s):  
Molecular Dynamics ◽  
Pure Aluminum ◽  
Critical Distance ◽  
Atomic Scale ◽  
Embedded Atom Method ◽  
Face Centered Cubic ◽  
Embedded Atom ◽  
Modified Embedded Atom Method ◽  
Face Centered ◽  
The Impact

The voids in pure Aluminum always exit in the manufacturing process. The Modified Embedded Atom Method (MEAM) potential is employed in the molecular dynamics (MD) simulation at atomic scale to investigate the interaction between voids under the impact loading for pure Aluminum. The distance between the voids distributed along the loading orientation affects the failure mechanism seriously. The results show that there are 3 kinds of mechanisms with the change of the distance between voids: 1) coalescence takes place within a critical distance between voids under extra loading, 2) when the distance between voids reaches a certain value, each void cracks at 4 locations along with the slide direction <110> of face-centered cubic (fcc), respectively, 3) a stress shield zone appears when the ligament between the voids is at the size between the cases mentioned above, which brings out the phenomena that each of the voids cracks only at 2 locations, and no crack appeared at the stress shield zone.

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