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Journal of the Korean Ceramic Society 1988;25(6): 704. |
상압소결한 Al2O3-SiC계 소결체의 기계적 성질(2) : SiC Whisker의 분산효과 |
김경수, 이홍림 |
연세대학교 공과대학 요업공학과 |
Mechanical Properties of the Pressureless Sintered Al2O3-SiC Composites(2) : Dispersion Effects of SiC Whisker |
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ABSTRACT |
In order to investigate the effect of the second phase on Al2O3 matrix, SiC whisker was dispersed in Al2O3 matrix as a second phase over the content range of 5vol% to 20vol%. To this mixture, Y2O3 or TiO2 powder was added as a sintering additive before isostatically pressing and pressureless sintering at 1800-190$0^{circ}C$ for 90min in N2 atmosphere. With increasing SiC whisker content, relative densities of composites were decreased and the grain growth of Al2O3 was restricted. When Y2O3 was added as a sintering aid the sintering temperature was 180$0^{circ}C$, the maximum values of flexural strength, hardness and fracture toughness were 537MPa, 12.1GPa, 3.7MPa.m1/2, respectively. However, when the sintering temperature was elevated to 190$0^{circ}C$, maximum values of flexural strength, hardness and fracture toughness were 453MPa, 17.5GPa, 4.9MPa.m1/2, respectively. Improved mechanical properties are assumed to be attributed to the crack deflection by the second phase SiC whisker and whisker pullout mechanism. |
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