The effect of grain size on the toughness of sintered Si sub 3 N sub 4
Three distinctive sintered Si{sub 3}N{sub 4} bodies were prepared and characterized on their toughness-controlling parameters. High strength sintered Si{sub 3}N{sub 4} bodies having K(IC) values of 6.5, 8.3, and 9.7 MN/m exp -3/2, respectively, were obtained by different chemistry, starting powders, and sintering conditions. The coarser microstructure body showed the tougher property. Grain size analysis results showed that beta-Si3N4 grain having a diameter larger than 1 micron affected results primarily by increased toughness. Crack propagation analysis showed the more frequently deflected and branched crack propagation gave the higher toughness. These results concluded that crack deflection and branching occurred preferably at the site of the beta-Si{sub 3}N{sub 4} grain having larger than 1 micron diameter. Consequently K(IC) of the coarse grain sintered Si{sub 3}N{sub 4} was relatively higher than that of the fine grain one. 6 refs.
- OSTI ID:
- 6977684
- Report Number(s):
- CONF-890130--
- Journal Information:
- Ceramic Engineering and Science Proceedings; (USA), Journal Name: Ceramic Engineering and Science Proceedings; (USA) Vol. 10; ISSN 0196-6219; ISSN CESPD
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360203* -- Ceramics
Cermets
& Refractories-- Mechanical Properties
CERAMICS
CRACK PROPAGATION
CRYSTAL STRUCTURE
ELECTRON MICROSCOPY
FRACTURE PROPERTIES
GRAIN SIZE
MECHANICAL PROPERTIES
MICROSCOPY
MICROSTRUCTURE
NITRIDES
NITROGEN COMPOUNDS
PNICTIDES
SILICON COMPOUNDS
SILICON NITRIDES
SIZE