K sup R -curve behavior of duplex ceramics

Journal Article · Tue Jan 01 00:00:00 EST 1991 · Journal of the American Ceramic Society; (United States)

DOI:https://doi.org/10.1111/j.1151-2916.1991.tb07289.x· OSTI ID:5161746

Lutz, E H; Claussen, N ^[1]; Swain, M V ^[2]

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1. Advanced Ceramics Group, Technical Univ. of Hamburg-Harburg, D-2100 Hamburg 90 (DE)
2. Div. of Material Science, Commonwealth Scientific and Industrial Research Organizaiton, Victoria 3168 (AU)

The fracture toughness behavior during crack growth (K{sub R}-curve behavior) of duplex ceramics is investigated. Different types of K{sup R}-curves can be distinguished depending on the microstructural designs of these materials which are characterized by the volume fraction and size of the dispersed pressure zones, and by their effective volume expansion. According to their K{sup R}-curve behavior, duplex ceramics can be subdivided into two groups consisting of short-range and long-range toughened materials. The experimental results are discussed regarding the appearance of different toughening mechanisms which are documented by crack path micrographs. An unusual toughening effect, a crack-branching chain reaction, is documented by in situ observations. The critical stress to nucleate the observed process zone development is calculated and compared with the internal stress intensity factor K{sub i} which has been previously proposed for these materials and with the material strength.

• OSTI ID: 5161746
• Journal Information: Journal of the American Ceramic Society; (United States), Vol. 74:1; ISSN 0002-7820
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM OXIDES
CRACK PROPAGATION
MECHANICAL PROPERTIES
ZIRCONIUM OXIDES
CERAMICS
FRACTURE MECHANICS
MICROSTRUCTURE
ALUMINIUM COMPOUNDS
CHALCOGENIDES
CRYSTAL STRUCTURE
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OXIDES
OXYGEN COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
ZIRCONIUM COMPOUNDS
360203* - Ceramics
Cermets
& Refractories- Mechanical Properties