Revealing the deformation mechanisms of 6H-silicon carbide under nano-cutting

Wu, Zhonghuai; Liu, Weidong; Zhang, Liangchi

doi:10.1016/j.commatsci.2017.05.048

Cited by 55 publications

(30 citation statements)

References 57 publications

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“…Despite substantial efforts, elastic‐plastic deformation and transition behaviors of 3C‐SiC at the nanoscale are not properly understood. Recently, deformation mechanisms at nano‐scales of other polytypes which includes amorphous, 4H and 6H–SiC have been studied . Besides, this study will also help in designing of nanoscale piezo electric, resistive and biomedical devices and sensors.…”

Section: Introductionmentioning

confidence: 97%

Nanoscale elastic‐plastic deformation and mechanical properties of 3C‐SiC thin film using nanoindentation

Nawaz

Islam

Mao

et al. 2018

Int J Applied Ceramic Tech

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The elastic-plastic deformation of 3C-SiC thin film was investigated by a nanoindenter equipped with the Berkovich tip. Transition from pure elastic to elasticplastic deformation was evidenced at an approximate load of 0.35 mN, when loading the sample at several peak loads ranging from 0.5 to 5 mN. The indentation size effect observed in 3C-SiC and was analyzed by Nix-Gao model. In purely elastic region, the Oliver-Pharr hardness values were 44 ± 2 GPa. In contrast, indentation size effects were evidenced in 3C-SiC specimen and the average value of Oliver-Pharr hardness in the indentation size effect region was 36 ± 2 GPa. Furthermore, depth independent or intrinsic hardness extracted from Nix-Gao was estimated as H o = 26 ± 1 GPa which was also validated by proportional specimen resistance model, ie, H 1 = 28 ± 1 and H 2 = 28.5 ± 0.1 GPa.Besides, energy principle was utilized to extract Sakai Hardness as 104 GPa, which is combined elastic and elastic-plastic response. Moreover, based on energy principle, another property, ie, work of indentation was also determined to be 20 nJ/μm 3 . Similarly, elastic modulus had almost depicted stabilized value of 325 ± 8 GPa in pure elastic and elastic-plastic regions. In addition, plastic zone size was also estimated in elastic-plastic region using Johnson cavity model at pop-in and higher loads. Based on the first pop-in load at 0.35 mN, the distributions of shear and principal stresses were evaluated on various slip planes to elaborate the deformation behavior. Increase in loading rate from 100 to 400 μN/s increased critical pop-in load from 0.35 to 0.64 mN. This increase in critical popin load with increasing loading rate and values of maximum contact pressure indicates that no phase assisted transformation will occur at pop-in load. Based on theoretically calculated maximum tensile and cleavage strengths, it was affirmed that the elastic-plastic deformation occurred due to pop-in formation rather than tensile stresses. Moreover, it was also concluded on basis of Hertzian contact theory and Schmidt law that the highest possibility of slippage in 3C-SiC was along the {111} glide plane. K E Y W O R D S

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Section: Introductionmentioning

confidence: 97%

Nanoscale elastic‐plastic deformation and mechanical properties of 3C‐SiC thin film using nanoindentation

Nawaz

Islam

Mao

et al. 2018

Int J Applied Ceramic Tech

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“…Wu et al studied the nanometric cutting deformation mechanism of 6H-SiC by MD simulation. It was believed that with the increase of cutting depth, 6H-SiC experienced the transition from elastic deformation to plastic deformation and then to intermittent cleavage (Wu et al, 2017). Xiao et al studied the relationship between cutting thickness and stress through MD simulation and concluded that when the cutting depth became small enough, the tensile stress would become lower than the critical tensile stress of brittle fracture, which was not enough to cause brittle fracture (Xiao et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

MD simulation of stress-assisted nanometric cutting mechanism of 3C silicon carbide

Liu

Hartmaier

et al. 2019

ILT

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Purpose This paper aims to reveal the mechanism for improving ductile machinability of 3C-silicon carbide (SiC) and associated cutting mechanism in stress-assisted nanometric cutting. Design/methodology/approach Molecular dynamics simulation of nano-cutting 3C-SiC is carried out in this paper. The following two scenarios are considered: normal nanometric cutting of 3C-SiC; and stress-assisted nanometric cutting of 3C-SiC for comparison. Chip formation, phase transformation, dislocation activities and shear strain during nanometric cutting are analyzed. Findings Negative rake angle can produce necessary hydrostatic stress to achieve ductile removal by the extrusion in ductile regime machining. In ductile-brittle transition, deformation mechanism of 3C-SiC is combination of plastic deformation dominated by dislocation activities and localization of shear deformation. When cutting depth is greater than 10 nm, material removal is mainly achieved by shear. Stress-assisted machining can lead to better quality of machined surface. However, there is a threshold for the applied stress to fully gain advantages offered by stress-assisted machining. Stress-assisted machining further enhances plastic deformation ability through the active dislocations’ movements. Originality/value This work describes a stress-assisted machining method for improving the surface quality, which could improve 3C-SiC ductile machining ability.

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“…The Tersoff potential [12] was adopted to describe the interatomic interactions in the SiC workpiece and the diamond cutting tool. The Morse potential [9] was adopted to describe the interatomic interaction between the SiC workpiece and the diamond cutting tool. Simulation results were visualized with Open Visualization Tool (OVITO) [13].…”

Section: Models and Methodsmentioning

confidence: 99%

“…They found that 4H-SiC shows the minimum subsurface lattice damage depth in contrast to 6H-SiC. Wu et al [9] revealed the deformation mechanisms of 6H-SiC through nanocutting MD simulations. They found that the plastic deformation of 6H-SiC can be realized by phase transformation and dislocations.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Nanocutting Characteristics of Off-Axis 4H-SiC Substrate by Molecular Dynamics

Wang

Zhu²,

Xu³

et al. 2018

Applied Sciences

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Silicon carbide (SiC), especially 4H-SiC, is an ideal semiconductor in power electronics due to its outstanding electrical and thermal properties. It has high hardness and brittleness, which makes it difficult to machine. To understand the nanomachining characteristics of off-axis 4H-SiC and provide suggestions on 4H-SiC substrate thinning, the nanocutting process of 4 ∘ off-axis 4H-SiC was simulated by molecular dynamics. The results showed that the stacking fault induced by cutting propagates in the basal plane, and propagates deep into the SiC workpiece when the angle between the cutting direction and the c-axis is smaller than 90 ∘ . Bond reconstruction is found near the slip plane. The cutting depth is also a key parameter in nanocutting. With smaller cutting depth, machining is more like scratching than cutting. With larger cutting depth, more atoms are involved in the cutting, cutting force and workpiece temperature are higher, and more defects exist.

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Revealing the deformation mechanisms of 6H-silicon carbide under nano-cutting

Cited by 55 publications

References 57 publications

Nanoscale elastic‐plastic deformation and mechanical properties of 3C‐SiC thin film using nanoindentation

Nanoscale elastic‐plastic deformation and mechanical properties of 3C‐SiC thin film using nanoindentation

MD simulation of stress-assisted nanometric cutting mechanism of 3C silicon carbide

Investigation of Nanocutting Characteristics of Off-Axis 4H-SiC Substrate by Molecular Dynamics

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