Ferroelasticity, mechanical behavior, and phase stability of t prime zirconia ceramics

Miscellaneous · Tue Jan 01 00:00:00 EST 1991

OSTI ID:5474886

Jue, Janfong

Large-grained (100-200 {mu}m), yttria doped, polycrystalline t{prime}-zirconia ceramics were fabricated by heating presintered samples at 2100C. Two point four and 3 mol% yttria-doped single crystals obtained from a commercial source were oriented by the Laue back-reflection method and cut along {l angle}100{r angle}, {l angle}110{r angle}, and {l angle}111{r angle} directions. They were also heat treated at 2100C. Ferroelastic domain structure was predicted by group theory and examined by transmission optical microscopy under polarized light and transmission electron microscopy. Orientations of domain boundaries were in accordance with predictions of group theory. X-ray diffraction showed that no monoclinic phase was detected on as-polished, ground, fracture surfaces, and on surfaces under tensile stresses as high as 400 MPa. Relative changes in the tetragonal peak intensities occurred and were attributed to ferroelastic domain switching. Higher toughness of 3 mol% Y{sub 2}O{sub 3} doped t{prime} samples (7.7MPam{sup 1/2}) compared to that of zirconia in the cubic phase (8 mol% Y{sub 2}O{sub 3}, 2.4MPam{sup 1/2}) was attributed in part to ferroelastic domain switching. Polished surfaces of polycrystalline t{prime}-materials showed no mono-clinic phase even after 1,000 hours at 275C in air, whereas conventional Y-TZP ceramics of a grain size larger than 0.5 {mu}m showed substantial transformation.

• Research Organization: Utah Univ., Salt Lake City, UT (United States)
• OSTI ID: 5474886
• Resource Relation: Other Information: Thesis (Ph.D.)
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
YTTRIUM OXIDES
METALLURGICAL EFFECTS
ZIRCONIUM OXIDES
MECHANICAL PROPERTIES
PHASE STUDIES
DOPED MATERIALS
FABRICATION
HEAT TREATMENTS
CHALCOGENIDES
MATERIALS
OXIDES
OXYGEN COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS
ZIRCONIUM COMPOUNDS
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