Relationship between microstructure, toughening mechanisms, and fracture toughness of reinforced silicon nitride ceramics

Journal Article · Sun Oct 01 04:00:00 EDT 1995 · Journal of the American Ceramic Society

DOI:https://doi.org/10.1111/j.1151-2916.1995.tb08031.x· OSTI ID:131526

Sajgalik, P; Hoffmann, M J ^[1]; Dusza, J ^[2]

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1. Max-Planck-Inst. fuer Metallforschung, Stuttgart (Germany)
2. Slovak Academy of Sciences, Kosice (Slovakia). Inst. of Materials Research

Different microstructures in Si{sub 3}N{sub 4} ceramics containing Y{sub 2}O{sub 3} and Al{sub 2}O{sub 3} as sintering additives were prepared by two-step sintering. Pull-out and elastic bridging were most frequently observed as the toughening mechanisms in samples with fine-grained microstructures having needlelike {beta}-Si{sub 3}N{sub 4} grains with diameters of < 1 {micro}m. Crack deflection was the main toughening mechanism observed in samples with coarse-grained microstructures having grains with diameters of > 1 {micro}m. The values of fracture toughness were varied from 6.1 to 8.2 MPa {center_dot} m{sup 1/2} with respect to the microstructural characteristics, characterized by the volume fraction of needlelike grains and their diameter.

• Sponsoring Organization: USDOE
• OSTI ID: 131526
• Journal Information: Journal of the American Ceramic Society, Journal Name: Journal of the American Ceramic Society Journal Issue: 10 Vol. 78; ISSN 0002-7820; ISSN JACTAW
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM OXIDES
BENCH-SCALE EXPERIMENTS
COMPOSITE MATERIALS
CRACK PROPAGATION
CRACKS
EXPERIMENTAL DATA
FRACTURE PROPERTIES
GRAIN SIZE
MICROSTRUCTURE
SAMPLE PREPARATION
SILICON NITRIDES
SINTERING
TEMPERATURE DEPENDENCE
YTTRIUM OXIDES