Research on the dynamic mechanical properties of C-plane sapphire under impact loading

Jiang, Feng; Luan, Xiaosheng; Wang, Ningchang; Xu, Xipeng; Lu, Xizhao; Wen, Qiuling

doi:10.1016/j.ceramint.2018.02.227

Cited by 55 publications

(13 citation statements)

References 35 publications

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“…When the growth defects are observed by the naked eye in the necking-down growth stage, and if crystal defects are not treated, the final sapphire crystal will have obvious defects in Fig.1 (c). These obvious crystal defects include cracks and abnormal growth [12].…”

Section: A Sapphire Growth Defectmentioning

confidence: 99%

A Novel Defect Diagnosis Method for Kyropoulos Process-Based Sapphire Growth

et al. 2020

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When sapphire crystal is prepared with Kyropoulos method, the necking-down growth process is a key stage. Sapphire growth defect is a big problem in this stage. However, diagnosing growth defects is subject to the interference of workers subjectivity and accuracy always goes down. To address the problem, a novel defect diagnosis method is proposed for necking-down growth process in this paper. Industrial CCD sensors replace eyes of skilled workers to observe in this method. A new Defect-Diagnosing Siamese network (DDSN) is used in this method. We use Siamese architecture to learn similarity through pairs of images. We use the deep separable convolution (DSC) into the DDSN to optimize running speed and model size. In experiment, dataset is acquired by industrial CCD sensors in the necking-down growth process. The accuracy of defect diagnosis can reach up to 94.5%. The method significantly improves the traditional way.

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Section: A Sapphire Growth Defectmentioning

confidence: 99%

A Novel Defect Diagnosis Method for Kyropoulos Process-Based Sapphire Growth

et al. 2020

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“…of sapphire has been obtained at different velocities. It was found that the crystal orientation influences the crack path and crack pattern, which leads to different energy consumption during crack propagation [17]. Wang et al used a Vickers indenter on a micrometer scale to study crack propagation that is induced by sequential indentation was investigated on the A-plane and C-plane of sapphire.…”

Section: Introductionmentioning

confidence: 99%

“…Konstantiniuk et al used chemical vapor deposition to deposit single crystal and polycrystalline α-Al 2 O 3 coatings on sapphire substrates with different crystal orientations, and prepared unnotched and notched microcantilevers. The (11)(12)(13)(14)(15)(16)(17)(18)(19)(20) single crystalline coating which was aligned for fracture on the C-plane, exhibited the highest fracture stress and fracture toughness [25]. Graça et al used the SEVNB method to explore the fracture resistance of single-crystal sapphire with different crystal orientations prepared by two processes.…”

Section: Introductionmentioning

confidence: 99%

“…In this paper, the fracture toughness of single-crystal sapphire with different crystal orientations was tested by three-point bending tests. Single crystal sapphire samples were prepared by the single-edge V-notch beam (SEVNB) method, including C-plane (0001), A-plane (11)(12)(13)(14)(15)(16)(17)(18)(19)(20), and M-plane (10-10) sapphires. In addition, this paper further considered the influence of the loaded surface during the three-point bending tests.…”

Section: Introductionmentioning

confidence: 99%

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Fracture Behavior of Single-Crystal Sapphire in Different Crystal Orientations

et al. 2021

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In order to study the anisotropy of fracture toughness and fracture mechanism of single-crystal sapphire, the three-point bending tests and the single-edge V-notch beam (SEVNB) were used to test the fracture toughness of A-plane, C-plane, and M-plane sapphire, which are widely used in the semiconductor, aerospace, and other high-tech fields. Fracture morphology was investigated by a scanning electron microscope and three-dimensional video microscopy. The fracture toughness and fracture morphology of different crystal planes of sapphire showed obvious anisotropy and were related to the loading surfaces. C-plane sapphire showed the maximal fracture toughness of 4.24 MPa·m1/2, and fracture toughness decreases in the order of C-plane, M-plane, and A-plane. The surface roughness is related to the dissipation of fracture energy. The surface roughness of the fracture surface is in the same order as C-plane > M-plane > A-plane. The fracture behavior and morphology of experiments were consistent with the theoretical analysis. C-plane sapphire cleavages along the R-plane with an angle of 57.6 degrees and the rhombohedral twin were activated. M-plane and A-plane sapphire cleavages along their cross-section.

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“…Based on current research, the double-sided planetary grinding using fixed fine diamond wheel was proposed to flatten the sapphire substrate in this paper. This kind of grinding has the same motion as the double-side lapping with free abrasives [25]. Due to the abrasives fixed on the wheel surface, the relative motion trajectory of abrasives and workpiece would become more uniform and controllable, which results in a good surface shape accuracy and more uniform surface quality [26].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Double-Sided Planetary Grinding Using Diamond Wheels for Sapphire Substrates

Wang

Huang

et al. 2018

Crystals

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Double-sided planetary grinding as an efficient and precise machining method is used for the rapid thinning and flattening process of sapphire substrate. As an intermediate processing technology of sapphire substrate preparation procedure, many experiments are carried out to evaluate the lapping effect in the paper. Surface quality, processing efficiency, and surface dent depth, which all impact subsequent polishing processes, are evaluated. Firstly, the four stages of grinding process are analyzed to display the surface accuracy changing process of the sapphire substrates during grinding. Secondly, the effect of three main grinding parameters (grinding pressure, rotation speed of the grinding wheels, and the grain size of grinding wheels) on surface accuracy and processing efficiency are investigated. Finally, sapphire removal rate of about 10 µm/min is achieved easily at the optimized condition with a good surface quality by double-sided planetary grinding. The double-sided planetary grinding with the ceramic-bonded diamond wheel is suitable for the rapid thinning and flattening of the sapphire substrate.

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Research on the dynamic mechanical properties of C-plane sapphire under impact loading

Cited by 55 publications

References 35 publications

A Novel Defect Diagnosis Method for Kyropoulos Process-Based Sapphire Growth

A Novel Defect Diagnosis Method for Kyropoulos Process-Based Sapphire Growth

Fracture Behavior of Single-Crystal Sapphire in Different Crystal Orientations

Evaluation of Double-Sided Planetary Grinding Using Diamond Wheels for Sapphire Substrates

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