Toughness properties of a silicon carbide with an in situ induced heterogeneous grain structure
- National Inst. of Standards and Technology, Gaithersburg, MD (United States). Materials Science and Engineering Lab.
Toughness characteristics of a heterogeneous silicon carbide with a coarsened and elongated grain structure and an intergranular second phase are evaluated relative to a homogeneous, fine-grain control using indentation--strength data. The heterogeneous material exhibits a distinctive flaw tolerance, indicative of a pronounced toughness curve. Quantitative evaluation of the data reveals an enhanced toughness in the long-crack region, with the implication of degraded toughness in the short-crack region. The enhanced long-crack toughness is identified with crack-interface bridging. The degraded short-crack toughness is attributed to weakened grain or interface boundaries and to internal residual stresses from thermal expansion mismatch. A profound manifestation of the toughness-curve behavior is a transition in the nature of mechanical damage in Hertzian contacts, from classical single-crack cone fracture in the homogeneous control to distributed subsurface damage in the heterogeneous material.
- OSTI ID:
- 6861916
- Journal Information:
- Journal of the American Ceramic Society; (United States), Journal Name: Journal of the American Ceramic Society; (United States) Vol. 77:10; ISSN 0002-7820; ISSN JACTAW
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360202 -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
360203* -- Ceramics
Cermets
& Refractories-- Mechanical Properties
CARBIDES
CARBON COMPOUNDS
CRACKS
DATA
DATA ANALYSIS
EXPERIMENTAL DATA
FRACTURE PROPERTIES
INFORMATION
MECHANICAL PROPERTIES
MICROSTRUCTURE
NUMERICAL DATA
SILICON CARBIDES
SILICON COMPOUNDS