Material removal mode and friction behaviour of RB-SiC ceramics during scratching at elevated temperatures

Rao, Xiaoshuang; Zhang, Feihu; Luo, Xichun; Ding, Fei; Cai, Yukui; Sun, Jining; Liu, Haitao

doi:10.1016/j.jeurceramsoc.2019.05.015

Cited by 38 publications

(17 citation statements)

References 53 publications

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“…Additionally, a pristine RB-SiC sample was polished with a diamond slurry having a particle size of 0.25 μm until a surface finish of 20 nm (Sa) was obtained, which was used to determine the subsurface damage in the EDDG process through comparison. In a previous study [24], X-ray diffraction analysis revealed that an RB-SiC sample primarily consisted of 6H-SiC phases. The main properties of the RB-SiC supplied by Goodfellow Cambridge Ltd. are listed in Table 1.…”

Section: Methodsmentioning

confidence: 85%

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Surface and subsurface damage of reaction-bonded silicon carbide induced by electrical discharge diamond grinding

Rao

Zhang

et al. 2020

International Journal of Machine Tools and Manufacture

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Reaction-bonded silicon carbide (RB-SiC) ceramic, one of the best candidates for large optical mirrors, is difficult to machine because of its high hardness and brittleness. A hybrid process called electrical discharge diamond grinding (EDDG) exhibits potential for improving the machinability of RB-SiC by combining electrical discharge machining (EDM) and diamond grinding. However, this hybrid process leads to damages that differ from those in conventional processes owing to the simultaneous actions of EDM and diamond grinding. In the present study, surface and subsurface damages induced by the interactions between EDM and diamond grinding during the EDDG of RB-SiC were examined. The effect of the discharge energy was considered.The surface and subsurface topographies and microstructures were characterized via scanning electron microscopy, Raman spectroscopy, and transmission electron microscopy. The EDM and grinding zones exhibited distinctive surface topographies and different dominant material removal mechanisms. An increase in the discharge energy facilitated ductile removal of the material and decomposition of SiC. Thus, a thinner subsurface damage layer was obtained compared with that in the less-thermally affected zone. The decomposed C and material migration tended to increase with the discharge energy. Owing to the interactions between EDM and diamond grinding, the subsurface was a mixture of amorphous/crystalline C, polycrystalline/nanocrystalline

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Section: Methodsmentioning

confidence: 85%

“…The discharge energy transferred to the workpiece changes the material properties of RB-SiC in the grinding zone, affecting the critical depth hc. In a previous study [24],…”

Section: Surface and Subsurface Damage Induced By The Interactionsmentioning

confidence: 88%

Surface and subsurface damage of reaction-bonded silicon carbide induced by electrical discharge diamond grinding

Rao

Zhang

et al. 2020

International Journal of Machine Tools and Manufacture

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“…In general, the friction force between indenter and groove surface is equal to the sum of the adhesion force and the ploughing force in the nanoscratching test [40,41], namely…”

Section: Theoretical Cof Model For Edge-forward and Face-forward Nanomentioning

confidence: 99%

Experimental and Numerical Investigation on the Effect of Scratch Direction on Material Removal and Friction Characteristic in BK7 Scratching

et al. 2020

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In order to study the influence of scratch direction on the deformation characteristics and material removal mechanism of optical glass BK7, nanoscratching experiments were conducted on a Nano indenter using Vickers indenter. Results indicate that the face-forward scratch is more likely to induce the initiation and propagation of lateral cracks, which is found to be more beneficial to material removal processes; in contrast, small chips and debris are released from the machined grooves without introducing lateral cracks in the edge-forward condition, leading to poor material removal efficiency. In addition, the choice of scratch direction can make differences to the elastic recovery rate of optical glass BK7. The results revealed that both the elastic recovery rate and the residual stresses of the material under the face-forward scratching are greater than those of the edge-forward scratching. A theoretical model for coefficient of friction (COF) under different scratch directions was established. It is found that the COF between indenter and workpiece in the edge-forward scratching is larger than the face-forward scratching under otherwise identical conditions, this finding is consistent with experimental results. A stress field analysis using finite element method (FEM) was conducted to understand the different crack initiation and propagation behaviors from different scratch directions. The current study discusses the significance of scratch direction on material removal behavior of optical glass BK7, and the results would encourage further research on investigating the connections between tool geometry and material removal mechanism.

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“…In the previous work [21,25], depth of cut. The ductile material removal mode can be obtained as the actual depth of cut is less than the critical depth of cut given by [26]:…”

Section: Machined Surface Integritymentioning

confidence: 99%

“…However, Eq. (1) has been modified by considering the variation of mechanical property at elevated temperatures in the previous work [25], which is given by:…”

Section: Machined Surface Morphologymentioning

confidence: 99%

Analysis of diamond wheel wear and surface integrity in laser-assisted grinding of RB-SiC ceramics

Rao

Zhang

et al. 2019

Ceramics International

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Laser-assisted grinding provides a promising solution for achieving costefficient machining of hard and brittle materials. However, the heat generated by laser may cause the wear of diamond grinding wheel, including the wear of both diamond grits and bond material. Consequently, wheel wear has a knock-on effect on the ground surface roughness. Moreover, the laser irritation may also induce damage in the machined surface. This paper focuses on the investigation of wear of diamond grinding wheel and surface integrity in laser-assisted grinding of RB-SiC ceramics. Different temperatures were obtained by setting the laser power to explore the influence of heat on wheel wear and surface integrity. The wear modes and mechanism of the diamond grits and bond material were analyzed by combination of SEM detection and energy dispersion spectrum analysis. The results revealed that adhesion and pullout of diamond grits in laser-assisted grinding were the remarkable difference from those in conventional grinding due to the thermal softening of both RB-SiC specimen and bond material of the grinding wheel. Surface roughness was then improved owing to the increase in active grits. The Raman spectra of the machined surface also revealed different stress conditions and microstructures of the Si and SiC Phase in RB-SiC ceramics. These results provided insight on quality control in laser-assisted machining of RB-SiC ceramics.

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Material removal mode and friction behaviour of RB-SiC ceramics during scratching at elevated temperatures

Cited by 38 publications

References 53 publications

Surface and subsurface damage of reaction-bonded silicon carbide induced by electrical discharge diamond grinding

Surface and subsurface damage of reaction-bonded silicon carbide induced by electrical discharge diamond grinding

Experimental and Numerical Investigation on the Effect of Scratch Direction on Material Removal and Friction Characteristic in BK7 Scratching

Analysis of diamond wheel wear and surface integrity in laser-assisted grinding of RB-SiC ceramics

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