New mechanism for toughening ceramic materials. Final report, 15 March 1989-15 July 1993
Ferroelastic toughening was identified as a viable mechanism for toughening ceramics. Domain structure and domain switching was identified by x-ray diffraction, transmission optical microscopy, and transmission electron microscopy in zirconia, lead zirconate titanate and gadolinium molybdata. Switching in compression was observed at stresses greater than 600 MPa and at 400 MPa in tension for polycrystalline t'-zirconia. Domain switching contributes to toughness, as evidenced by data for monoclinic zirconia, t'-zirconia, PZT and GMO. The magnitude of toughening varied between 0.6 MPa.ml/2 for GMO to 2-6 MPa-ml/2 for zirconia. Polycrystalline monoclinic and t'-zirconias, which showed no transformation toughening, had similar toughness values as Y-TZP which exhibits transformation. Coarse-grained monoclinic and tetragonal (t') zirconia samples could be cooled to room temperature for mechanical property evaluation since fine domain size, not grain size, controlled transformation for t'-zirconia and minimized stress for m-ZrO2. LnAlO3, LnNbO4, and LnCrO3 were among the materials identified as high temperature ferroelastics.
- Research Organization:
- Ceramatec, Inc., Salt Lake City, UT (United States)
- OSTI ID:
- 7108178
- Report Number(s):
- AD-A-278479/1/XAB; CNN: F49620-89-C-0054; DARPA ORDER-5994
- Country of Publication:
- United States
- Language:
- English
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Ferroelastic domain switching as a toughening mechanism in tetragonal zirconia
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Related Subjects
360203* -- Ceramics
Cermets
& Refractories-- Mechanical Properties
CERAMICS
CHALCOGENIDES
DOCUMENT TYPES
DOMAIN STRUCTURE
FRACTURE PROPERTIES
GADOLINIUM COMPOUNDS
LEAD COMPOUNDS
MECHANICAL PROPERTIES
MOLYBDATES
MOLYBDENUM COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PROGRESS REPORT
PZT
RARE EARTH COMPOUNDS
REFRACTORY METAL COMPOUNDS
TITANATES
TITANIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
YIELD STRENGTH
ZIRCONATES
ZIRCONIUM COMPOUNDS
ZIRCONIUM OXIDES