Thermally activated martensitic transformations in Mg-PSZ
- Case Western Reserve Univ., Cleveland, OH (United States). Dept. of Materials Science and Engineering
The thermally activated, stress-assisted martensitic tetragonal {yields} monoclinic (t {yields} m) and tetragonal {yields} orthorhombic (t {yields} o) transformations in a high-toughness Mg-PSZ were investigated by monitoring the phase assemblage with Raman spectroscopy after a variety of heat treatments and loading conditions. After a short anneal at 1,000 C, which transforms m- and o-ZrO{sub 2} to the t polymorph, isothermal t {yields} m and t {yields} o transformations occur at room temperature during the months following the anneal. The transformation rates in the annealed samples are greatly enhanced under external stress. Alternatively, samples containing regions of significant residual stress, introduced by indentation for example, and then annealed at relatively low temperatures, underwent additional thermally activated transformation in the stressed regions. The thermodynamics and kinetics of this complex transformation ``plasticity,`` and its effect on mechanical properties, are discussed.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 247908
- Journal Information:
- Journal of the American Ceramic Society, Journal Name: Journal of the American Ceramic Society Journal Issue: 4 Vol. 79; ISSN 0002-7820; ISSN JACTAW
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CRYSTAL-PHASE TRANSFORMATIONS
HEAT TREATMENTS
KINETICS
MAGNESIUM OXIDES
MECHANICAL PROPERTIES
MONOCLINIC LATTICES
NEUTRON DIFFRACTION
ORTHORHOMBIC LATTICES
RAMAN SPECTROSCOPY
STRAINS
STRESS RELAXATION
STRESSES
TETRAGONAL LATTICES
THERMODYNAMICS
X-RAY DIFFRACTION
ZIRCONIUM OXIDES