Transformation toughening of ceramics. Annual report No. 2, 15 Jan 90-11 Jan 91

Technical Report · Fri Feb 01 04:00:00 EST 1991

OSTI ID:5470910

Marshall, D B

The transformation strains responsible for toughening of ZrO2 materials have been measured directly using Moire interferometry and a high resolution strain mapping technique based on digital image correlation. Results were correlated with Raman spectroscopy and finite element calculations. Calculations of the crack tip shielding in Ce-ZrO2 indicated that the fracture toughness could be increased by a factor of 2 by modifying the microstructure to change the shape of the transformation zone ahead of the crack tip. Layered composites of Ce-ZrO2 and Al2O3/Ce-ZrO2 have been explored as a means of achieving such zone modifications. Using a colloidal technique, multilayered composites with layer thickness as small as 10 microns have been fabricated. These layered structures have been observed to interact much more strongly than expected with the transformation zones, causing widening of the zone to the side of cracks as well as modification of the frontal region. The potential exists for extremely high fracture toughness in such systems.

• Research Organization: Rockwell International Corp., Thousand Oaks, CA (United States). Science Center
• OSTI ID: 5470910
• Report Number(s): AD-A-234926/4/XAB; SC--71002.AR; CNN: F49620-89-C-0031
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360203* -- Ceramics
Cermets
& Refractories-- Mechanical Properties
360603 -- Materials-- Properties
ALLOYS
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CERIUM ALLOYS
CHALCOGENIDES
COLLOIDS
COMPOSITE MATERIALS
CORRELATIONS
CRACKS
CRYSTAL STRUCTURE
DIGITAL SYSTEMS
DIMENSIONS
DISPERSIONS
FINITE ELEMENT METHOD
FRACTURE PROPERTIES
IMAGES
INTERFEROMETRY
LASER SPECTROSCOPY
LAYERS
MATERIALS
MECHANICAL PROPERTIES
MICROSTRUCTURE
MODIFICATIONS
NUMERICAL SOLUTION
OXIDES
OXYGEN COMPOUNDS
RAMAN SPECTROSCOPY
RARE EARTH ALLOYS
SHIELDING
SPECTROSCOPY
THICKNESS
TRANSFORMATIONS
TRANSITION ELEMENT COMPOUNDS
ZIRCONIUM COMPOUNDS
ZIRCONIUM OXIDES