The effect of microstructure on mechanical properties of alumina-based composites by particulate-precipitated dispersion
- Univ. of Tokyo (Japan)
Alumina-based ceramic composites which second phases have a microstructure of equiaxed grains as YAG or elongated grains as LaAl11O18 by reaction of Al{sub 2}O{sub 3} and additives during hot-pressing, were fabricated using particulate-precipitated dispersion. The Al{sub 2}O{sub 3}/SiC/YAG hybrid composites having the equaxied second phase were fabricated in the temperature range from 1000 to 1800{degrees}C using SiC and Y{sub 2}O{sub 3} powders as additive. Then, YAG (yttrium aluminum garnet, Y3Al5O12) phase was formed as the second phase from the reaction between Al{sub 2}O{sub 3} and Y{sub 2}O{sub 3} above 1400{degrees}C hot-pressing temperature. The grain size of monolithic Al{sub 2}O{sub 3} increased with increasing hot-pressing temperature and hot-pressing time, while that of Al{sub 2}O{sub 3} increased with increasing hot-pressing temperature and hot-pressing time, while that of Al{sub 2}O{sub 3}/SiC/YAG hybrid composites was effectively restrained due to the incorporation of YAG and SiC particulate into Al{sub 2}O{sub 3} matrix. Also, Al{sub 2}O{sub 3}/LBA(lanthanum-{beta}-alumina, LaAl11O18) composites having an elongated second phase were successfully fabricated using Al{sub 2}O{sub 3} powder as additives. The properties of hot-pressed bodies, such as microstructural observation by SEM & TEM, phase analysis by XRD, strength, toughness, toughening mechanism etc., were investigated. The mechanical properties of flexural strength and fracture toughness of composites were higher than that of monolithic Al{sub 2}O{sub 3}. Also, the composites having elongated grains showed higher toughness due to grain bridging than the composites having equaxied second phase.
- OSTI ID:
- 96547
- Report Number(s):
- CONF-940416--
- Country of Publication:
- United States
- Language:
- English
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