Transformation toughened and whisker reinforced ceramics
Studies of transformation toughened alumina ceramics containing dispersions of zirconia particles have led to the development of high tensile strength (up to 1000 MPa, approx. 150,000 psi as measured in a four-point flexure test) Al/sub 2/O/sub 3/-ZrO/sub 2/ composite materials with K/sub IC/ values (8 to 13 MPa.m/sup 1/2/) which are two- to threefold greater than those of the toughest conventional ceramics. In addition, these composites exhibit much better resistance to static fatigue than do alumina ceramics. Development of SiC whisker reinforced oxide ceramic composites has also resulted in composites with fracture toughness values of up to 9 MPa.m/sup 1/2/ (Al/sub 2/O/sub 3/-20 vol % SiC whiskers). These studies indicate that the toughening process involves a whisker pullout mechanism. This toughening process is also activated during slow crack growth (fatigue) and, hence, substantially increases the slow crack growth resistance of the composite.
- Research Organization:
- Oak Ridge National Lab., TN (USA)
- DOE Contract Number:
- W-7405-ENG-26
- OSTI ID:
- 5685975
- Report Number(s):
- CONF-831142-1; ON: DE84003281
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360303* -- Composite Materials-- Mechanical Properties-- (-1987)
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CARBIDES
CARBON COMPOUNDS
CHALCOGENIDES
COMPOSITE MATERIALS
CRACK PROPAGATION
CRYSTALS
FRACTURE PROPERTIES
MATERIALS
MECHANICAL PROPERTIES
MONOCRYSTALS
OXIDES
OXYGEN COMPOUNDS
REINFORCED MATERIALS
SILICON CARBIDES
SILICON COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
WHISKERS
YTTRIUM COMPOUNDS
YTTRIUM OXIDES
ZIRCONIUM COMPOUNDS
ZIRCONIUM OXIDES