Molecular dynamics simulation of chip formation mechanism in single-crystal nickel nanomachining

Zhu, Zongxiao; Peng, Bin; Feng, Ruoqiang; Wang, Linjun; Jiao, Shi; Dong, Yun

doi:10.1007/s11431-019-9520-8

Cited by 17 publications

(4 citation statements)

References 29 publications

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“…The boundary layer always keeps the atoms fixed, i.e., subjected to no atomic vibrations, maintains periodic boundary conditions along the x and y directions, and free boundary conditions in the z direction to eliminate boundary effects; the constant temperature layer is utilized to keep the system temperature constant; the Newtonian layer is the focus of microfriction and wear research, and it satisfies Newton's second law of motion. [26][27][28] The conjugate gradient method has been used for energy minimization in the relaxation process to eliminate unreasonable factors for model building, such as atomic overlap. [29] Table 1 lists the parameters chosen for the simulation in this work.…”

Section: Friction Modeling and Simulation Processmentioning

confidence: 99%

Study of metal–ceramic WC/Cu nano-wear behavior and strengthening mechanism

Zheng¹,

Chen²,

Zhu³

et al. 2023

Chinese Phys. B

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In view of the inherent poor tribological properties of copper, the reinforcement of Copper Matrix Composites with WC particles presents a promising research area with significant industrial impact. Therefore, in that current study, a molecular dynamics approach was used to simulate the process of repeated friction of diamond grinding balls on WC/Cu composites, and the friction force, friction coefficient, abrasion depth, wear rate, abrasion morphology, von-Mises stress, internal defects, workpiece energy, and performance comparison of different layer thicknesses were systematically investigated during the multiple friction processes. It was found that the fluctuation amplitude of friction force, friction coefficient, and abrasion depth were smaller and the fluctuation frequency was larger during the initial friction, whereas near the WC phase, extreme values of the above parameters appeared and the von-Mises stress was highly concentrated while the workpiece energy continued to increase. With the repeated friction, as the number of times of friction increases, the friction force, friction coefficient, and abrasion depth fluctuation amplitude increases, the fluctuation frequency decreases, the workpiece energy appears extreme near the WC phase, and a large number of dislocation plugging, the region is strengthened, with the distance between the grinding ball and the WC phase decreases, the more obvious the strengthening effect, the stronger the workpiece anti-wear ability.

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Section: Friction Modeling and Simulation Processmentioning

confidence: 99%

Study of metal–ceramic WC/Cu nano-wear behavior and strengthening mechanism

Zheng¹,

Chen²,

Zhu³

et al. 2023

Chinese Phys. B

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“…V-shaped dislocations are the most common manifestations of defects in nickel-based single-crystal friction processes [38]. Figure 9(a) shows the evolution of a V-shaped dislocation within the workpiece, and figure 9(b) shows a clear structure of the V-shaped dislocation at three different stages of evolution.…”

Section: Evolution Of the Morphology Of The Wear Marks And Internal D...mentioning

confidence: 99%

Molecular dynamics study of the repetitive friction mechanism of nickel-based single crystals in an aqueous environment

Zheng¹,

Zhang²,

Zhu³

et al. 2023

Phys. Scr.

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In this study, molecular dynamics simulations were used to simulate the iterative rotational friction of nickel-based single crystals using diamond grinding balls in both the presence and absence of water. First, the friction force, depth and morphology of wear marks, wear rate, and evolution of internal defects during the friction process of nickel-based single crystals were investigated. Second, a comparative study of the frictional wear of nickel-based single crystals in both the presence and absence of water was carried out in terms of temperature, water molecule distribution, atomic displacement vector, and wear scar depth during the friction process. Finally, the formation process of irregular grinding chips under aqueous conditions was elucidated. The following phenomena were observed: As the number of rubs increased, the single rub depth of the workpiece, the wear rate, and the rate of increase in the number of defective atoms produced all decreased. A comparison of friction under aqueous and water-free conditions showed that, in the presence of water, the force exerted by the grinding ball on the workpiece was shared by the water molecules. This resulted in a decrease in the roughness of the machined surface, a reduction in the number of internally generated layer errors, a lower overall friction temperature, and a nickel matrix that was protected by water molecules. Finally, when grinding under aqueous conditions, water molecules interfered with the normal chip removal process of the grinding balls, leading to the production of irregular grinding chips.

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“…Fixed, constant temperature, and Newton layer assumptions were used for the workpiece and tool. The fixed layer supported the entire workpiece and prevented it from moving during friction [27]. The yellow atom between the fixed layer and the substrate was the constant temperature layer, which adopted the Berendsen thermal bath method [28].…”

Section: Modeling and Simulation Detailsmentioning

confidence: 99%

Molecular Dynamics Simulation of Chip Morphology in Nanogrinding of Monocrystalline Nickel

Wei

Wang

et al. 2022

Coatings

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In this study, the nanogrinding process for single-crystal nickel was investigated using a molecular dynamics simulation. A series of simulations were conducted with different tool radii and grinding methods to explore the effects of chip morphology, friction forces, subsurface damage, and defect evolution on the nanogrinding process. The results demonstrate that the workpiece atoms at the back of the tool were affected by the forward stretching and upward elastic recovery when no chips were produced. Although the machining depth was the smallest, the normal force was the largest, and dislocation entanglement was formed. The small number of defect atoms indicates that the extent of subsurface damage was minimal. Moreover, when spherical chips were produced, a typical columnar defect was generated. The displacement vector of the chip atoms aligned with the machining direction and as the chips were removed by extrusion, the crystal structure of the chip atoms disintegrated, resulting in severe subsurface damage. By contrast, when strip chips were produced, the displacement vector of the chip atoms deviated from the substrate, dislocation blocks were formed at the initial stage of machining, and the rebound-to-depth ratio of the machined surface was the smallest.

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Molecular dynamics simulation of chip formation mechanism in single-crystal nickel nanomachining

Cited by 17 publications

References 29 publications

Study of metal–ceramic WC/Cu nano-wear behavior and strengthening mechanism

Study of metal–ceramic WC/Cu nano-wear behavior and strengthening mechanism

Molecular dynamics study of the repetitive friction mechanism of nickel-based single crystals in an aqueous environment

Molecular Dynamics Simulation of Chip Morphology in Nanogrinding of Monocrystalline Nickel

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