Influence of Al/sub 2/O/sub 3/ on properties of yttria-stabilized zirconia-Al/sub 2/O/sub 3/ composites. Interim report, October 1985-April 1986

Technical Report · Tue Apr 15 00:00:00 EST 1986

OSTI ID:5459513

Buchanan, R C; Davison, W W

Composite structures of yttria (4.5 mol%)-stabilized zirconia (YSZ) with added Al/sub 2/O/sub 3/ (0.3 to 7.5 wt%) were investigated. Pressed YSZ compacts prepared from submicrometer powders of >99% purity were sintered in the range 1200 to 1350 C for 0,5 to 24 h. Uniform-grain-size microstructures (0.2 to 0.4 micrometers) were obtained which showed discrete Al/sub 2/O/sub 3/ grains dispersed throughout. X-ray-diffraction and Raman spectral analysis indicated a combination of both cubic and tetragonal phases. Measured lattice parameters were observed to vary irregularly with Al/sub 2/O/sub 3/ content. DC conductivity was found to increase with added Al/sub 2/O/sub 3/ less than 3 wt%. Strength vaules obtained for the composites were in excess of 9 Mpa x the squareroot of M (K sub Ic) and 425 MPa (MOR), significantly higher thatn reported for cubic phase YSZ. The increased strength was attributed to small grain size as well as to crack deflection and arrest mechanisms associated with the dispersed high modulus and lower-expansion second phase. The presence of a monoclinic phase was not detected in the samples either before or after fracture, hence the strengthening could not be ascribed to transformation toughening.

• Research Organization: Illinois Univ., Urbana (USA). Dept. of Ceramic Engineering
• OSTI ID: 5459513
• Report Number(s): AD-A-167328/4/XAB; TR-13
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM OXIDES
COMPOSITE MATERIALS
STABILIZATION
YTTRIUM OXIDES
ZIRCONIUM OXIDES
CRACKS
CRYSTAL LATTICES
DIRECT CURRENT
GRAIN SIZE
POWDERS
SINTERING
ALUMINIUM COMPOUNDS
CHALCOGENIDES
CRYSTAL STRUCTURE
CURRENTS
ELECTRIC CURRENTS
FABRICATION
MATERIALS
MICROSTRUCTURE
OXIDES
OXYGEN COMPOUNDS
SIZE
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS
ZIRCONIUM COMPOUNDS
360302* - Composite Materials- Structure & Phase Studies- (-1987)
360303 - Composite Materials- Mechanical Properties- (-1987)