The polymorphic transformations of zirconia

Conference · Thu Jan 01 04:00:00 EST 1987

OSTI ID:5046516

Chan, S K

The polymorphic transformations of zirconia are elucidates as displacive transformations originating from the softening or partial softening of appropriate elastic constants. From expansions of the free energy in powers of symmetry-adapted homogeneous strains, all the possible symmetry and thermodynamically allowed tranformation paths staring from the cubic and tetragonal parent phases are obtained. It is found that transformations that start from the cubic parent phase involve cubic variants and are necessarily of a discontinuous (first order) nature because of symmetry. However, transformations that start from the tetragonal parent phase do not involve cubic invariants. They can be of a discontinuous or continuous (higher than first order) nature depending on whether the fourth order invariants are negative or positive. 18 refs., 2 tabs.

• Research Organization: Argonne National Lab., IL (USA)
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 5046516
• Report Number(s): CONF-870843-11; ON: DE88009985
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360202* -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
CHALCOGENIDES
CRYSTAL LATTICES
CRYSTAL STRUCTURE
CUBIC LATTICES
ELASTICITY
ENERGY
FREE ENERGY
MECHANICAL PROPERTIES
OXIDES
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
SYMMETRY
TENSILE PROPERTIES
THERMODYNAMIC PROPERTIES
THERMODYNAMICS
TRANSITION ELEMENT COMPOUNDS
ZIRCONIUM COMPOUNDS
ZIRCONIUM OXIDES