Relationship between Grinding Mechanism and Residual Cracks in Single Point Grinding Test of Alumina Ceramics with Different Grain Sizes

Tsukuda, Akira; Kondo, Yoshinori; Kuroshima, Yasuyuki; Uematsu, Keizo

doi:10.2109/jcersj.103.268

Cited by 8 publications

(3 citation statements)

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“…Here, this series of cracks is termed herringbone cracks. They are similar in appearance to that obtained in the pendulum single grit scratch test 32 . This finding lends supports to the hypothesis that the elongated blade‐like QPD zone and the herringbone cracks are formed by a single scratch with an abrasive grit on the grinding wheel surface.…”

Section: Resultssupporting

confidence: 85%

Visualization of Subsurface Damage in Silicon Nitride from Grinding by a Plasma Etching and Dye Impregnation Method

Kanematsu

2006

Journal of the American Ceramic Society

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In order to develop a spatial morphology model of subsurface damage in grinding of hot‐pressed silicon nitride, the damage has been investigated using visualization techniques, plasma etching, and a dye impregnation method developed in our previous work. The plasma etching technique resolved subsurface damage formed by a single abrasive grit on a grinding wheel surface. The damage consists of a grain‐released area, which has an overall shape approximately that of a blade like a willow leaf, and a series of bow‐like crack series that appear repeatedly along the grit‐scratching direction. By coupling these results with previous conclusions about the geometry of the strength‐controlling cracks in a flexural test specimen, we were able to develop a spatial model of subsurface damage morphology. The most distinctive feature of the model is the absence of a transverse crack, whose presence is commonly accepted in existing work on subsurface damage by grinding. The applicability of the model to the fracture behavior of a longitudinally ground flexural test specimen was verified by fractography and dye impregnation.

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Section: Resultssupporting

confidence: 85%

Visualization of Subsurface Damage in Silicon Nitride from Grinding by a Plasma Etching and Dye Impregnation Method

Kanematsu

2006

Journal of the American Ceramic Society

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“…Matsuo 6 and Tukuda 7 reported that machined monolithic alumina recovered strength considerably by heat treatment. However, the strength recovery was not complete.…”

Section: Introductionmentioning

confidence: 99%

Strength recovery of machined Al₂O₃/SiC composite ceramics by crack healing

Ono

Nakao

Takahashi

et al. 2007

Fatigue Fract Eng Mat Struct

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A B S T R A C T Alumina is used in various fields as a machine component. However, it has a low fracture toughness, which is a weakness. Thus, countless cracks may be initiated randomly by machining, and these cracks decrease the component's mechanical properties and reliability.To overcome this problem, a crack-healing ability could be a very useful technology. In this study, Al 2 O 3 /SiC composite was sintered. This alumina exhibits excellent crackhealing ability. Small specimens for a bending test were made from the Al 2 O 3 /SiC. A semicircular groove was machined using a diamond ball-drill. The machining reduced the local fracture stress from approximately 820-300 MPa. The machined specimens were crack-healed under various conditions. The fracture stress of these specimens after crack healing was evaluated systematically from room temperature (RT) to 1573 K. It was found that the local fracture stress of the machined specimen recovered almost completely after crack healing. Therefore, it was concluded that crack healing could be an effective method for improving the structural integrity of machined alumina and reducing machining costs.

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“…The locally processed alumina for these experiments presents a heterogeneous microstructure composed by grains with different morphology and sizes. Materials with these characteristics have weak grain boundaries, making the cracks go around the grains [13,[19][20][21][22]. On the other hand, the glass does not deflect the discontinuities, and this is the reason why it was chosen.…”

Section: Specimenmentioning

confidence: 99%

Detection of cracks in scratching tests in ceramic materials through acoustic emission

Sanchez

Oliveira

Coelho

2005

Proceedings of the Institution of Mechanical Engineers, Part B:

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The mechanisms of material removal and the interactions among scratches performed in ceramic materials were investigated using acoustic emission signals, and scanning electron microscopy, in scratching experiments. Several testing conditions were used to produce different types of removing mechanism on a glass as well as on a polycrystalline alumina sample composed by heterogeneous grain size. It is known that the material removing process on a polycrystalline ceramic involves intergranular microfracture and grain dislodgement, unlike the chipping produced by the extension of lateral cracks in non-granular materials, such as glass. Distinct settings for velocities, loads, and two types of diamond indenter were tested. The material removal was carried out by three different methods of scratching: single passes, repeated overlapping passes, and parallel scratches. As a general result, there was a clear relationship between the acoustic emission signals and the damage intensity occurred in the material removal. More specifically there were differences in the acoustic emission signal levels in the scratches made on the alumina and on the glass owing to the material removal mechanisms associated with the structure of these materials. A gradual increase in the acoustic emission levels was observed when the number of repeated passes was increased as a result of the damage accumulation process followed by severe material removal. It was also noticed that the acoustic emission signals were capable of reflecting the interactions between two parallel scratches.

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Relationship between Grinding Mechanism and Residual Cracks in Single Point Grinding Test of Alumina Ceramics with Different Grain Sizes

Cited by 8 publications

References 0 publications

Visualization of Subsurface Damage in Silicon Nitride from Grinding by a Plasma Etching and Dye Impregnation Method

Visualization of Subsurface Damage in Silicon Nitride from Grinding by a Plasma Etching and Dye Impregnation Method

Strength recovery of machined Al₂O₃/SiC composite ceramics by crack healing

Detection of cracks in scratching tests in ceramic materials through acoustic emission

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Relationship between Grinding Mechanism and Residual Cracks in Single Point Grinding Test of Alumina Ceramics with Different Grain Sizes

Cited by 8 publications

References 0 publications

Visualization of Subsurface Damage in Silicon Nitride from Grinding by a Plasma Etching and Dye Impregnation Method

Visualization of Subsurface Damage in Silicon Nitride from Grinding by a Plasma Etching and Dye Impregnation Method

Strength recovery of machined Al2O3/SiC composite ceramics by crack healing

Detection of cracks in scratching tests in ceramic materials through acoustic emission

Contact Info

Product

Resources

About

Strength recovery of machined Al₂O₃/SiC composite ceramics by crack healing