Premium
Significance of Internal Stresses for the Martensitic Transformation in Yttria‐Stabilized Tetragonal Zirconia Polycrystals During Degradation
Author(s) -
SCHMAUDER S.,
SCHUBERT H.
Publication year - 1986
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1986.tb04789.x
Subject(s) - materials science , tetragonal crystal system , nucleation , yttria stabilized zirconia , crystallite , monoclinic crystal system , cubic zirconia , diffusionless transformation , transmission electron microscopy , annealing (glass) , crystallography , surface energy , mineralogy , composite material , metallurgy , martensite , crystal structure , microstructure , ceramic , thermodynamics , nanotechnology , chemistry , physics
Various aspects of the tetragonal ( t ) to monoclinic ( m ) transformation during degradation have been studied experimentally and theoretically in yttria‐stabilized tetragonal zirconia polycrystals (Y‐TZP), i.e., polycrystalline t ‐ZrO 2 containing Y 2 O 3 in solution. Transmission electron microscopy (TEM) revealed that protruding grains at the surface of Y‐TZP specimens do not transform under corrosive conditions (250°C, humid atmosphere) even after an annealing time of 168 h. Eigenstresses due to anistropic thermal expansion In and around protruding and bulk grains have been calculated for Y‐TZP containing 2 and 3 mol% Y 2 O 3 . The prominent role of these stresses on subsequent transformation nucleation during degradation is shown to agree qualitatively with an established free energy concept. The lack of complete transformation of m ‐ZrO 2 is attributed to characteristics of the nucleation‐ and growth‐controlled transformation process.