Effect of MnO on the microstructures, phase stability and mechanical properties of ceria-partially-stabilized zirconia (Ce-TZP) and Ce-TZP-Al sub 2 O sub 3 composites

Journal Article · Sat Sep 01 04:00:00 EDT 1990 · Journal of Materials Research; (USA)

DOI:https://doi.org/10.1557/JMR.1990.1948· OSTI ID:6198013

Wang, J S; Tsai, J F; Shetty, D K; Virkar, A V ^[1]

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1. Department of Materials Science and Engineering, University of Utah, Salt Lake City, UT (USA)

Effect of increasing amounts of MnO additions on the microstructures, phase stability and mechanical properties of ZrO{sub 2}-12 m% CeO{sub 2} and ZrO{sub 2}-12 m% CeO{sub 2}-10 w% Al{sub 2}O{sub 3} were studied. MnO suppressed grain growth in ZrO{sub 2}-12 m% CeO{sub 2}, while enhancing the mechanical properties significantly (strength=557 MPa, fracture toughness=9.3 MPa.(m){sup 1/2} at 0.2 w% MnO). The enhanced mechanical properties were achieved despite an increased stability of the tetragonal phase as evidenced by a lower burst transformation temperature (M{sub b}) and a reduced volume fraction of the monoclinic phase on the fracture surface. In ZrO{sub 2}-12 m% CeO{sub 2}-10 w% Al{sub 2}O{sub 3}, the addition of MnO suppressed the grain size of ZrO{sub 2}, while promoting grain growth and changing the morphology of Al{sub 2}O{sub 3}. More significantly, the stability of the tetragonal ZrO{sub 2} phase decreased (high M{sub b} temperature) with a concurrent increase in fracture toughness (13.2 MPa.(m){sup 1/2} at 2 w% MnO) and transformation plasticity (1.2% in four-point bending). The widths of the transformation zones observed adjacent to the fracture surfaces showed a consistent inverse relation to the transformation yield stress as would be expected from the mechanics of stress-induced phase transformation at crack tips. The improvements in mechanical properties obtained in the base Ce-TZP and the Ce-TZP-Al{sub 2}O{sub 3} composite ceramics with the addition of MnO are critically examined in the context of transformation toughening and other possible mechanisms.

• DOE Contract Number: FG02-87ER45312
• OSTI ID: 6198013
• Journal Information: Journal of Materials Research; (USA), Journal Name: Journal of Materials Research; (USA) Vol. 5:9; ISSN JMREE; ISSN 0884-2914
• 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
ALKALINE EARTH METAL COMPOUNDS
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CERIUM COMPOUNDS
CERIUM OXIDES
CHALCOGENIDES
COMPOSITE MATERIALS
CRYSTAL STRUCTURE
DATA
EXPERIMENTAL DATA
FAILURES
FRACTURES
GRAIN GROWTH
INFORMATION
MAGNESIUM COMPOUNDS
MAGNESIUM OXIDES
MATERIALS
MECHANICAL PROPERTIES
MICROSTRUCTURE
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
PHASE STABILITY
PLASTICITY
RARE EARTH COMPOUNDS
STABILITY
TRANSITION ELEMENT COMPOUNDS
VERY HIGH PRESSURE
ZIRCONIUM COMPOUNDS
ZIRCONIUM OXIDES