Surface damage in ZrB2-based composite ceramics induced by electro-discharge machining

Nakamura, Mamoru; Shigematsu, Ichinori; Kanayama, Kozo; Hirai, Y.

doi:10.1007/bf01113887

Cited by 26 publications

(8 citation statements)

References 3 publications

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“…This result can be explained considering the different surface finish obtained with EDM and DLT. The EDM produces samples characterized by a higher level of microdamage and a higher roughness, and therefore, presumably, a higher surface area, with respect to DLT 23,24 . Actually, looking at Table II, it can be noted that EDM materials, while having a close R t parameter of the DLT samples, are characterized by a higher arithmetic mean deviation of the assessed profile ( R a ) with respect to DLT ones.…”

Section: Resultsmentioning

confidence: 96%

“…Thanks to the relatively high electrical conductivity (≅10 6 S/cm), 13 sintered ZrB 2 and HfB 2 ceramics can be shaped by means of electrical discharge machining (EDM). Even though ED‐machined surfaces are generally characterized by a higher roughness and by a higher level of surface microdamage than diamond‐loaded tooled (DLT) ones, EDM has indeed proven to be an effective and flexible technique to machine UHTC pieces into more complex components 23,24 …”

Section: Introductionmentioning

confidence: 99%

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Effect of the Machining Method on the Catalycity and Emissivity of ZrB₂ and ZrB₂–HfB₂‐Based Ceramics

Scatteia¹,

Alfano²,

Monteverde³

et al. 2008

Journal of the American Ceramic Society

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The emissivity and the catalytic efficiency related to atomic oxygen recombination were investigated experimentally in the range 1000-2000 K for ZrB 2 and ZrB 2 -HfB 2 -based ceramics. In order to evaluate the effect of the machining method, two series of samples, one prepared by electrical discharge machining and the other machined by diamond-loaded tools, were tested. High emissivity (about 0.7 at 1700 K) and low recombination coefficients (on average 0.08 at 1800 K) were found for all the materials. The experimental data showed an effect of the surface machining on the catalytic behavior only on the ZrB 2 -based composite; conversely, small variations were found in the recombination coefficients of ZrB 2 -HfB 2 -based samples for the different machining processes. The surface finish affected the emissivity at lower temperatures in both compositions, with the effect becoming negligible at temperatures above 1500 K.

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Section: Resultsmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

Effect of the Machining Method on the Catalycity and Emissivity of ZrB₂ and ZrB₂–HfB₂‐Based Ceramics

Scatteia¹,

Alfano²,

Monteverde³

et al. 2008

Journal of the American Ceramic Society

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“…6 Tomlinson and Jupe, 7 Fu, Wu and Liu 8 and Nakamura et al 9 have characterized the surface damage induced by EDM on brittle materials. Thin slices are cut using a diamond saw or wire electric discharge machining.…”

Section: Specimen Cutting and Preparationmentioning

confidence: 99%

Tensile testing of microsamples

LaVan

Sharpe

1999

Experimental Mechanics

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Structural analysis has advanced rapidly to the point where lack of knowledge about the local inhomogeneity and anisotropic nature of the materials prevents the accurate prediction of the behavior; models can incorporate local material properties provided they can be experimentally determined. Conventional tensile techniques are unable to test specimens from submillimeter-sized regions, and microhardness measurements do not reveal directional variations. A system has been developed to perform tensile tests on microsamples that are 3.1 mm long with a gage cross section that is 0.2 mm square. The volume of the test region is roughly 500,000 times smaller than a standard half-inch diameter specimen. Tensile stress-strain curves are measured, and the yield strength, ultimate strength, modulus and elongation are calculated for each sample. Samples cut from the weld metal of undermatched welds in HY-100 plate showed a large variation in properties from the center of the weld to the outer edge, as well as anisotropy at some locations. The average mechanical properties of a group of microsamples cut from the outer region of the weldment compared favorably with measurements made using full-sized specimens; the variation in the microsample measurements reflect local variations in the material that are not measured with full-sized specimens.

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“…The feasibility of EDM on cemented tungsten carbide was also investigated by several researchers, and their experimental data revealed that EDM is an efficient process to shape the cemented tungsten carbide (Pandit and Rajukar, 1981;Levy and Wertheim, 1988;Puertas et al, 2004). Low thermal conductivity and brittleness cause the cemented tungsten carbide to exhibit micro-cracks on its machined surface, created by the thermal stress during EDM (Lee et al, 1988;Ramulu and Garbini, 1991;Endo et al, 1991;Nakamura et al, 1991;Lee et al, 1992;Lee and Li, 2003). Therefore, the defects on the machined surface, such as micro-cracks and micro-pores, severely reduce the service life, reliability and machining precision of a tool or a mould made of cemented tungsten carbide.…”

Section: Introductionmentioning

confidence: 98%

Effects of electrical discharge energy on machining performance and bending strength of cemented tungsten carbides

Lin

Hwang

Cheng

et al. 2008

Journal of Materials Processing Technology

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Surface damage in ZrB2-based composite ceramics induced by electro-discharge machining

Cited by 26 publications

References 3 publications

Effect of the Machining Method on the Catalycity and Emissivity of ZrB₂ and ZrB₂–HfB₂‐Based Ceramics

Effect of the Machining Method on the Catalycity and Emissivity of ZrB₂ and ZrB₂–HfB₂‐Based Ceramics

Tensile testing of microsamples

Effects of electrical discharge energy on machining performance and bending strength of cemented tungsten carbides

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Surface damage in ZrB2-based composite ceramics induced by electro-discharge machining

Cited by 26 publications

References 3 publications

Effect of the Machining Method on the Catalycity and Emissivity of ZrB2 and ZrB2–HfB2‐Based Ceramics

Effect of the Machining Method on the Catalycity and Emissivity of ZrB2 and ZrB2–HfB2‐Based Ceramics

Tensile testing of microsamples

Effects of electrical discharge energy on machining performance and bending strength of cemented tungsten carbides

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Product

Resources

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Effect of the Machining Method on the Catalycity and Emissivity of ZrB₂ and ZrB₂–HfB₂‐Based Ceramics

Effect of the Machining Method on the Catalycity and Emissivity of ZrB₂ and ZrB₂–HfB₂‐Based Ceramics