Mechanical Behavior of Single Crystalline and Polycrystalline Silicon Carbides Evaluated by Vickers Indentation.

Kitahara, Hiromoto; Noda, Yoko; Yoshida, Fuyuki; Nakashima, Hideharu; Shinohara, Nobuhiro; Abe, Hiroshi

doi:10.2109/jcersj.109.1271_602

Cited by 33 publications

(14 citation statements)

References 1 publication

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“…14,15 Shockley partial dislocations bordering intrinsic stacking faults are thought to be most relevant in hexagonal SiC, 5,16 with mobility of leading partials exceeding that of trailing partials at low temperatures, 17 supporting a tendency for plasticity to be accompanied by generation of large numbers of stacking faults. 20 The present work addresses nonlinear behavior of single crystals of 6H-SiC. 18͒ does not appear to be an important mechanism in hexagonal polytypes, except at high temperatures and pressures wherein phase transformations occur.…”

Section: Introductionmentioning

confidence: 97%

Modeling nonlinear electromechanical behavior of shocked silicon carbide

Clayton

2010

Journal of Applied Physics

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A model is developed for anisotropic ceramic crystals undergoing potentially large deformations that can occur under significant pressures or high temperatures. The model is applied to describe silicon carbide (SiC), with a focus on α-SiC, specifically hexagonal polytype 6H. Incorporated in the description are nonlinear anisotropic thermoelasticity, electrostriction, and piezoelectricity. The response of single crystals of α-SiC of various orientations subjected to one-dimensional shock loading is modeled for open- and short-circuit boundary conditions. The influences of elastic and electromechanical nonlinearity and anisotropy on the response to impact are quantified. For elastic axial compressive strains less than 0.1, piezoelectricity, electrostriction, and thermal expansion have a negligible influence on the mechanical (stress) response, but the influences of nonlinear elasticity (third-order elastic constants) and anisotropy are not insignificant. The model is extended to incorporate inelastic deformation and lattice defects. Addressed are Shockley partial dislocations on the basal plane and edge dislocation loops on the prism plane, dilatation from point defects and elastic fields of dislocation lines, and cleavage fracture. The results suggest that electric current generated in shock-loaded α-SiC crystals of certain orientations could affect the dislocation mobility and hence the yield strength at high pressure.

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Section: Introductionmentioning

confidence: 97%

Modeling nonlinear electromechanical behavior of shocked silicon carbide

Clayton

2010

Journal of Applied Physics

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“…It has been long suggested that silicon carbide (SiC) would be a competitor material to ULE and Zerodur for building the next-generation large-scale reflecting mirrors, particularly used in the space-based telescope, owing to its high stiffness-to-density ratio and low thermal distortion properties [5][6][7]. However, SiC is a typical difficult-to-machine material because of its extreme hardness, only lower than diamond, cubic boron nitride (cBN), and boron carbide (B 4 C) [8]. The extreme hardness induced an extremely low material removal rate.…”

Section: Introductionmentioning

confidence: 99%

High-performance grinding of a 2-m scale silicon carbide mirror blank for the space-based telescope

Zhang

Yang

Zheng

et al. 2016

Int J Adv Manuf Technol

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Silicon carbide (SiC) is a competitive candidate material for building the space-based reflecting mirrors. However, SiC is also a typical difficult-to-machine material due to its extreme hardness. When SiC workpiece is machined by grinding, the wheel wears rapidly which leads to a deterioration of surface form accuracy. Grinding efficiency also becomes extremely low due to the frequent truing and dressing of grinding wheels. To achieve high-performance grinding process capable of producing accurate surface at high grinding efficiency, an ultrasonic vibration-assisted fix-point grinding technology was developed in this study. Wheel wear observation indicated that the wheel needs not to be dressed during the whole grinding cycle. Moreover, a laser tracker was used to achieve an on-machine measurement of the surface form error. A CNC tool microset was adopted to evaluate the wheel wear amount. On the basis of the above two results, surface form error could be predicted before grinding, and thus, an inprocess compensation of surface form error was carried out. Using the above-mentioned grinding strategies, a SiC mirror blank with an aperture diameter of 2 m was successfully ground to a form accuracy of 18 μm in peak-to-valley (PV). Therefore, this work provides an efficient and economical solution for grinding the large-scale SiC aspherical surfaces.

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“…The mechanical properties of SiC single crystals depended on the crystal planes. 14) Development of texture in SiC by hot forging 15) and the Templated Grain Growth method 16) has been reported. On the other hand, the crystallographic orientation even in feeble magnetic ceramics, such as Al 2 O 3 and AlN, etc., can be controlled by a colloidal processing under a magnetic field.…”

Section: Introductionmentioning

confidence: 99%

Texture development of surface-modified SiC prepared by EPD in a strong magnetic field

Suzuki

Uchikoshi

Sakakibara

et al. 2011

J. Ceram. Soc. Japan

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Silicon carbide is a very important material for various applications and its properties are expected to be improved by controlling the crystallographic orientation. It was difficult to simultaneously consolidate SiC powder and sintering additives by electrophoretic deposition (EPD) because of the different electrophoretic mobility. When using the alumina-coated SiC by the solgel method, it is possible to deposit SiC and sintering additives by EPD at the same time.In this study, we demonstrated that the c-axis alignment of SiC was controlled by EPD and a strong magnetic field, and we investigated the effect of the surface-modification on the microstructure and the degree of orientation. The dilute solution and the large number of repeated coating times prevent the oxide phase from precipitating at the multiple grain junctions and enhance grain growth. The grain growth promoted the degree of orientation in the textured SiC prepared by EPD in a strong magnetic field.

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Mechanical Behavior of Single Crystalline and Polycrystalline Silicon Carbides Evaluated by Vickers Indentation.

Cited by 33 publications

References 1 publication

Modeling nonlinear electromechanical behavior of shocked silicon carbide

Modeling nonlinear electromechanical behavior of shocked silicon carbide

High-performance grinding of a 2-m scale silicon carbide mirror blank for the space-based telescope

Texture development of surface-modified SiC prepared by EPD in a strong magnetic field

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