Strength and Toughness of Tailored Ceramic Microstructures
Final rept. 1 Sep 1987-31 Oct 1990
LEHIGH UNIV BETHLEHEM PA MATERIALS RESEARCH CENTER
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AFOSR project 87-0396 was undertaken to develop a detailed understanding of the link between microstructural variables and the strength and toughness of ceramic materials. A major emphasis of this effort has been developing approaches for producing multiphase ceramic microstructures with enhanced reliability i.e. elevated temperature microstructural stability and damage tolerance andor room temperature flaw tolerance. Improvements in elevated temperature damage tolerance depend upon having a dual phase interconnected microstructure with more than 16 volume percent second phase. Our findings show that adding cubic zirconia to alumina improves damage tolerance in the that A1203 with 50 cZr02 AZ50 shows the same hardness yet appreciably less indentation damage than alumina at 1200 C and is very resistant to grain coarsening for up to 100 hours at 1650 C. Also, A1203 with 50 YAG AY50 has twice the hardness of A1203 at 1200 C.
- Laminates and Composite Materials