Deformation mechanisms and mechanical properties of nanocrystalline CuxNi100−x alloys during indentation using molecular dynamics

Vu, Thi-Nhai; Pham, Van-Trung; Fang, Te‐Hua

doi:10.1016/j.mtcomm.2022.104282

Cited by 13 publications

(6 citation statements)

References 66 publications

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“…As shown in figure 1, the sample is divided into three regions: boundary layer, thermostat layer, and Newtonian layer atoms [17][18][19][20]. The boundary and thermostat layers are 5 Å and 10 Å thickness, respectively.…”

Section: Physical Model and Methodsmentioning

confidence: 99%

Material deformation mechanism of lamellar twined high–entropy alloys during machining

Vu,

Pham,

Fang

2024

Modelling Simul. Mater. Sci. Eng.

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The effects of sample structure and tool geometry are studied under cutting simulation to verify the deformation, removal mechanisms, and subsurface defection of lamellar twined CoCuFeNiPd alloys. These findings suggest that the twin boundary spacing and twin inclination angle (β) are the main determinants of surface wear characteristics and cutting-induced surface harm. The maximum cutting force achieved with TBS = 8a and β =900. The high friction coefficient with the sample has TBS = 8a and β = 900, showing that the tool's moving in the substrate is strongly restricted. Furthermore, the surface topography is not sensitive to the TBS and β. The best-machined surface is achieved with TBS = 3a and 4a under twin inclinations of 0 and 300. The effect of edge radius (R), rake angle (γ), and clearance angle (α) on the deformation behavior is examined. The negative of γ, small α, or larger R results in a higher cutting force, a worse subsurface, and a lower cutting pile-up height. With a positive γ, a large α or small R has a larger average friction coefficient, which implies a higher resistance rate. The tool with a smaller R or positive γ can improve the machined surface's smoothness.

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Section: Physical Model and Methodsmentioning

confidence: 99%

Material deformation mechanism of lamellar twined high–entropy alloys during machining

Vu,

Pham,

Fang

2024

Modelling Simul. Mater. Sci. Eng.

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“…The lattice constant of the FCC structure is 3.539 Å [28]. In all cases, the substrate indentation depth was 15 Å [29,30] and the indenter tooltip was loaded and unloaded at 50 m s −1 [31,32]. These values were selected based on several considerations, including simulation feasibility, and relevance to the study.…”

Section: Simulation Modelmentioning

confidence: 99%

“…where the six stress components for each atom τ xy , τ yz , τ zx , δ xx , δ yy , and δ zz are calculated using the LAMMPS software. The von Mises shear invariant η vM is then employed to measure and assess plastic deformation, and is calculated using the following formula [32]:…”

Section: Interaction Between Atomsmentioning

confidence: 99%

“…These findings suggest the occurrence of subsurface damage mechanisms, including SFs, PDs, vacancy defects, and twinning (T). Notably, these defects become more pronounced with decreasing alloy composition, a phenomenon attributed to the release of stored elastic energy and variations in internal stress [32]. Specifically, amorphous and BCC structures are more prevalent in substrates with lower Ni composition The dislocation distributions for different alloy compositions are presented in figure 6.…”

Section: Effect Of Alloy Compositionmentioning

confidence: 99%

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Study of nanoindentation behavior of NiCrCoAl medium entropy alloys under indentation process using molecular dynamics

Ngo,

Nguyen,

Fang

2024

Modelling Simul. Mater. Sci. Eng.

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The mechanical properties and deformation behavior of CoCrNiAl medium entropy alloy (MEA) subjected to indentation by an indenter tooltip on the substrate are explored using molecular dynamics (MD) simulation. The study investigates the effects of alloy compositions, temperature variations, and ultra vibration (UV) on parameters, such as total force, shear strain, shear stress, hardness, reduced modulus, substrate temperature, phase transformation, dislocation length, and elastic recovery. The findings indicate that higher alloy compositions result in increased total force, hardness, and reduced modulus, with Ni-rich compositions demonstrating superior mechanical strength. Conversely, increasing alloy compositions lead to reduced von Mises stress (VMS), phase transformation, dislocation distribution, and dislocation length due to the larger atomic size of Ni compared to other primary elements. At elevated substrate temperatures, atoms exhibit larger vibration amplitudes and interatomic separations, leading to weaker atomic bonding and decreased contact force, rendering the substrate softer at higher temperatures. Additionally, higher initial substrate temperatures enhance atom kinetic energy and thermal vibrations, leading to reduced material hardness and increased VMS levels. Increasing vibration frequency enlarges the indentation area on the substrate's surface, concentrating shear strain and VMS with vibration frequency. Higher vibration amplitude and frequency amplify force, shear strain, VMS, substrate temperature, and dislocation distribution. Conversely, lower vibration amplitude and frequency result in a smaller average elastic recovery ratio. Moreover, increased amplitude and frequency values yield an amorphous-dominated indentation region and increased proportions of HCP and BCC structures. Furthermore, this study also takes into account the evaluation of a material's ability to recover elastically during the indentation process, which is a fundamental material property.

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“…In fact, with high short-range ordering of Cu-Ni clusters in the Cu, the plastic deformation in the adjacent glide planes is restricted, which prevents cross slip [16]. In the investigation of the effect of nanoindentation on the deformation mechanism of Cu-Ni alloy, Vu et al have reported that the dislocation motion and rotation of grain boundaries play a significant role in the deformation behavior of polycrystal alloy [17]. In fact, sliding and twisting of grain boundaries as well as the fusion of grains results in preventing the spread of strain and stress which considerably increases the alloy strength [18].…”

Section: Introductionmentioning

confidence: 99%

Using Molecular Dynamic Simulation to Understand the Deformation Mechanism in Cu, Ni, and Equimolar Cu-Ni Polycrystalline Alloys

Yazdani

Vitry

2023

Alloys

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The grain boundaries and dislocations play an important role in understanding the deformation behavior in polycrystalline materials. In this paper, the deformation mechanism of Cu, Ni, and equimolar Cu-Ni alloy was investigated using molecular dynamic simulation. The interaction between dislocations and grain boundary motion during the deformation was monitored using the dislocation extraction algorithm. Moreover, the effect of stacking fault formation and atomic band structure on the deformation behavior was discussed. Results indicate that dislocations nucleate around the grain boundary in copper, the deformation in nickel changes from planar slip bands to wavy bands, and high density of dislocation accumulation as well as numerous kink and jog formations were observed for the equimolar Cu-Ni alloy. The highest density of the Shockley dislocation and stacking faults was formed in the equimolar Cu-Ni alloy which results in the appearance of a huge gliding stage in the stress–strain curve. The grain boundaries act as a sinking source for vacancy annihilation in Ni and Cu; however, this effect was not observed in an equimolar Cu-Ni alloy. Finally, radial distribution function was used to evaluate atom segregation in grain boundaries.

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Deformation mechanisms and mechanical properties of nanocrystalline CuxNi100−x alloys during indentation using molecular dynamics

Cited by 13 publications

References 66 publications

Material deformation mechanism of lamellar twined high–entropy alloys during machining

Material deformation mechanism of lamellar twined high–entropy alloys during machining

Study of nanoindentation behavior of NiCrCoAl medium entropy alloys under indentation process using molecular dynamics

Using Molecular Dynamic Simulation to Understand the Deformation Mechanism in Cu, Ni, and Equimolar Cu-Ni Polycrystalline Alloys

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