Superplasticity in fine-grained 20% Al[sub 2]O[sub 3]/YTZ composite

Journal Article · Sun Dec 01 04:00:00 EST 1991 · Acta Metallurgica; (United States)

OSTI ID:7018698

Nieh, T G; Wadsworth, J ^[1]

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1. Lockheed Missiles and Space Co., Palo Alto, CA (United States)

This paper reports on the microstructure and superplastic deformation of fine-grained, 20% Al[sub 2]O[sub 3]-reinforced, yttria-stabilized, tetragonal zirconia (Al[sub 2]O[sub 3]/YTZ). Hot indention and tensile tests were carried out at temperatures between 1000[degrees] and 1650[degrees]C. The material exhibited extensive plasticity at temperatures higher tan 1200[degrees]C, and a maximum tensile elongation of over 624% was recorded. The microstructure of the Al[sub 2]O[sub 3]/YTZ was thermally unstable, and concurrent grain growth, and in particular dynamic grain growth, was observed at temperatures higher than 1450[degrees]C. Although the apparent strain rate sensitivity exponent was determined to be approximately 0.5, the true strain rate sensitivity, after compensation for grain growth, is about 0.67. The activation energy for superplasticity in Al[sub 2][sub 3]/YTZ was determined to be 257 kJ/mol which is much lower than the activation energy for superplastic Y-TZP.

• OSTI ID: 7018698
• Journal Information: Acta Metallurgica; (United States), Journal Name: Acta Metallurgica; (United States) Vol. 39:12; ISSN 0001-6160; ISSN AMETAR
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360202* -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
360203 -- Ceramics
Cermets
& Refractories-- Mechanical Properties
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Cermets
& Refractories-- Physical Properties
664400 -- Experimentally Derived Information on Atomic & Molecular Properties-- (1992-)
74 ATOMIC AND MOLECULAR PHYSICS
ALLOYS
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
AUGER ELECTRON SPECTROSCOPY
CHALCOGENIDES
CRYSTAL LATTICES
CRYSTAL STRUCTURE
DEFORMATION
ELECTRON MICROSCOPY
ELECTRON SPECTROSCOPY
GRAIN BOUNDARIES
MATERIALS
MICROSCOPY
MICROSTRUCTURE
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
REINFORCED MATERIALS
SPECTRA
SPECTROSCOPY
TETRAGONAL LATTICES
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSMISSION ELECTRON MICROSCOPY
X-RAY SPECTRA
YTTRIUM ADDITIONS
YTTRIUM ALLOYS
ZIRCONIUM COMPOUNDS
ZIRCONIUM OXIDES