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Phase Distribution and Residual Stresses in Melt‐Grown Al 2 O 3 ‐ZrO 2 (Y 2 O 3 ) Eutectics
Author(s) -
Harlan Nicole R.,
Merino Rosa I.,
Peña José I.,
Larrea Angel,
Orera Victor M.,
González Carlos,
Poza Pedro,
LLorca Javier
Publication year - 2002
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.1151-2916.2002.tb00399.x
Subject(s) - monoclinic crystal system , cubic zirconia , materials science , tetragonal crystal system , yttria stabilized zirconia , eutectic system , microstructure , mineralogy , phase (matter) , residual stress , crystallography , analytical chemistry (journal) , composite material , crystal structure , chemistry , ceramic , organic chemistry , chromatography
Al 2 O 3 ‐ZrO 2 eutectics containing 0 to 12.2 mol% Y 2 O 3 (with respect to zirconia) were produced by directional solidification using the laser floating zone (LFZ) method. Processing variables were chosen to obtain homogeneous, colony‐free, interpenetrating microstructure for all of the compositional range, optimum from the viewpoint of mechanical properties. The amount of cubic, tetragonal, or monoclinic zirconia phases was determined using a combination of Raman and X‐ray diffraction techniques. Monoclinic zirconia was present up to concentrations of 3 mol% Y 2 O 3 , while the amount of tetragonal zirconia gradually increased with yttria content up to 3 mol%. Cubic zirconia was the only phase detected when the yttria content reached 12 mol%. The residual stresses in alumina were measured using the shift of the ruby R lines. Compressive stresses were isotropic when measured in the samples containing tetragonal and cubic zirconia, while higher tensile, anisotropic stresses were found when monoclinic zirconia was present. They were partially relieved in the eutectic sample without yttria. These results were compared with a thermoelastic analysis based on the self‐consistent model.