Deformation anisotropy of nano-scratching on C-plane of sapphire: A molecular dynamics study and experiment

Lin, Jiaming; Jiang, Feng; Wen, Qiuling; Wu, Yueqin; Lu, Jing; Tian, Zige; Wang, Ningchang

doi:10.1016/j.apsusc.2021.149091

Cited by 54 publications

(14 citation statements)

References 42 publications

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“…On the other hand, it can be observed that burrs are likely to occur in the lateral direction when scratched in the 30 and 90 degrees directions (see, half circles of B 0 and B 1 ). These trends are almost the same as that of the MD simulation results obtained by Lin, et al [ 17 ]. Furthermore, it can be also observed when scratched in the 15, 45 and 75 deg.…”

Section: MD Simulation Results and Discussionsupporting

confidence: 90%

“…Nanoscratch is becoming a promising characterization method to analyze wear behavior and the nano-tribological property of a material under the dynamic state [ 14 , 15 ]. However, there are few studies focused on the machining anisotropy of monocrystalline sapphire in the ductile-regime by nanoscratch or similar methods which have clarified particularly the effect of the tool rake angle [ 16 ] and the slip/twinning systems [ 17 ] on the deformation states—even though it is important to clarify the deformation and removal mechanisms including the anisotropy, which are particularly concerned with the machining efficiency and machined surface and sub-surface qualities.…”

Section: Introductionmentioning

confidence: 99%

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Analysis of Nanoscratch Mechanism of C-Plane Sapphire with the Aid of Molecular Dynamics Simulation of Hcp Crystal

et al. 2021

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In this study, single groove nanoscratch experiments using a friction force microscope (FFM) with a monocrystalline diamond tip were conducted on a c-plane sapphire wafer to analyze the ductile-regime removal and deformation mechanism including the anisotropy. Various characteristics, such as scratch force, depth, and specific energy for each representative scratch direction on the c-plane of sapphire, were manifested by the FFM, and the results of the specific scratch energy showed a trend of six-fold symmetry on taking lower values than those of the other scratch directions when the scratch directions correspond to the basal slip directions as 0001⟨112¯0⟩. Since this can be due to the effect of most probably basal slip or less probably basal twinning on the c-plane, a molecular dynamics (MD) simulation of zinc, which is one of the hexagonal close-packed (hcp) crystals with similar slip/twining systems, was attempted to clarify the phenomena. The comparison results between the nanoscratch experiment and the MD simulation revealed that both the specific scratch energy and the burr height were minimized when scratched in the direction of the basal slip. Therefore, it was found that both the machining efficiency and the accuracy could be improved by scratching in the direction of the basal slip in the single groove nanoscratch of c-plane sapphire.

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Section: MD Simulation Results and Discussionsupporting

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Analysis of Nanoscratch Mechanism of C-Plane Sapphire with the Aid of Molecular Dynamics Simulation of Hcp Crystal

et al. 2021

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“…Molecular dynamics simulations have been frequently used to study surface scratching on an atomistic basis. Such studies have been performed mostly for metallic samples, but also for ceramic materials and metallic glasses [1][2][3][4][5][6][7][8][9][10][11][12][13]. As a result, information on the mechanisms of plastic deformation in these samples was obtained [11,14] that is useful for applications such as ultra-precision machining [15,16].…”

Section: Introductionmentioning

confidence: 99%

Multiple Scratching: An Atomistic Study

2023

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Using molecular dynamics simulation, we investigate multiple scratching processes in which a tip moves through a groove that has already been formed during a previous scratch. We use a conical indenter such that the friction coefficient is independent of the scratch depth. First, a single scratch to a depth of 4 nm is compared with a 2-cycle scratch in which a scratch at depth 2 nm is followed by a second scratch to the full depth of 4 nm. We observe that the second cycle shows a smaller friction coefficient as long as the tip moves through the pre-formed groove without touching the front end. In addition, we studied 5 cycles of scratching, in which the scratch depth was increased by 2 nm in each cycle. These results confirm and generalize the findings for the 2-cycle scratch. A constant-load 2-cycle scratch simulation emphasizes that the reduction in transverse load—and, consequently, in the friction coefficient—is caused by the fact that, despite a large normal area supporting the normal load, only a thin area is available to resist the transverse movement of the scratch tip. The work done during scratching is in good approximation proportional to the scratch volume showing that the transverse hardness is approximately constant in all scratch processes investigated here.

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“…A combination of molecular dynamics (MD) simulations and experiments has also been used to study the influence of anisotropy on the deformation mechanisms of C‐plane α‐Al 2 O 3 during the scratching process. [ 18 ] In both approaches, amorphization of crystals, basal slip, and rhombohedral slip in the subsurface were observed. However, while cracks appear in the experimental results, they have not yet been observed in MD simulations.…”

Section: Introductionmentioning

confidence: 99%

The Tensile Deformation of Multiphase Al₂O₃: Insights from Molecular Dynamics Simulations

Dinh

Nguyen

et al. 2022

Physica Status Solidi (b)

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Multiphase Al2O3 samples are simulated using molecular dynamics method. These samples consist of γ‐Al2O3 and α‐Al2O3 crystals embedded in a disordered phase matrix. The stress–strain curves of these samples show elastic and plastic deformation. Structural analysis indicates that the AlO bond lengths are stretched and the geometries of the AlOx (x = 4, 5, and 6) units are distorted during tensile deformation. AlO bond breakage causes the transformation of AlOx units; AlO4 increases while AlO6 decreases with increasing strain. The γ‐Al2O3 and α‐Al2O3 crystals transfer into the disordered phase, while a small number of atoms recrystallize under tensile loads. In plastic deformation, large simplexes with radii above 1.958 Å increase rapidly with increasing strains above 0.116, with the large simplexes coalescing to form the clusters in the disordered phase. The number of large simplexes in the largest cluster increases with increasing strain values above 0.127. The growth and coalescence of large simplexes in the disordered phase cause microscopic crack formation at high strains.

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Deformation anisotropy of nano-scratching on C-plane of sapphire: A molecular dynamics study and experiment

Cited by 54 publications

References 42 publications

Analysis of Nanoscratch Mechanism of C-Plane Sapphire with the Aid of Molecular Dynamics Simulation of Hcp Crystal

Analysis of Nanoscratch Mechanism of C-Plane Sapphire with the Aid of Molecular Dynamics Simulation of Hcp Crystal

Multiple Scratching: An Atomistic Study

The Tensile Deformation of Multiphase Al₂O₃: Insights from Molecular Dynamics Simulations

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Deformation anisotropy of nano-scratching on C-plane of sapphire: A molecular dynamics study and experiment

Cited by 54 publications

References 42 publications

Analysis of Nanoscratch Mechanism of C-Plane Sapphire with the Aid of Molecular Dynamics Simulation of Hcp Crystal

Analysis of Nanoscratch Mechanism of C-Plane Sapphire with the Aid of Molecular Dynamics Simulation of Hcp Crystal

Multiple Scratching: An Atomistic Study

The Tensile Deformation of Multiphase Al2O3: Insights from Molecular Dynamics Simulations

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Product

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The Tensile Deformation of Multiphase Al₂O₃: Insights from Molecular Dynamics Simulations