Transformation toughening of ceramics. Final report, 1 April 1992-30 April 1995

Technical Report · Fri Sep 01 04:00:00 EDT 1995

OSTI ID:200165

Marshall, D B

This report summarizes the results from a 3-year research program aimed at developing a basic understanding of the microstructural design, fabrication, and properties of multilayered zirconia-based composites with high toughness and oxidation resistance. Most of the effort focused on multilayered composites of Ce-ZrO2 and Al2O3 which have strongly bonded interfaces. The design of the layered composite microstructure was based on micromechanics analysis: the layers modify the shape and extent of a crack tip transformation zone, leading to toughnesses over 20 MPa.m1/2. Optimum layer thicknesses were determined and related to effects of autocatalytic transformation and crack tip advance mechanisms. Crack resistance curves were measured at various temperatures: the very high toughnesses (> 10 MPa.m1/2) were limited to temperature range of approx. 100 deg C above the Ms temperature for the martensitic transformation. A preliminary study of multilayered composites containing weakly bonded layers (which achieve toughening by debonding) indicated that rare earth phosphates (LaPO4 and CePO4) are potentially suitable layers for Y- and Ce-stabilized zirconia composites.

• Research Organization: Rockwell International Corp., Thousand Oaks, CA (United States). Science Center
• OSTI ID: 200165
• Report Number(s): AD-A--299692/4/XAB; CNN: Contract F49620-92-C-0028
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM OXIDES
CERAMICS
CERIUM ADDITIONS
COMPOSITE MATERIALS
CORROSION RESISTANCE
FRACTURE PROPERTIES
INTERFACES
LAYERS
PROGRESS REPORT
YTTRIUM ADDITIONS
ZIRCONIUM OXIDES