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Microstructural evolution and mechanical properties of gas-pressure-sintered Si3N4 with Yb2O3 as a sintering aid

Published online by Cambridge University Press:  31 January 2011

Ki-Min Lee
Affiliation:
Creative Research Center for Microstructural Science of Materials, School of Materials Science and Engineering, Seoul National University, Seoul, 151–742, Korea
Won-Ho Lee
Affiliation:
Creative Research Center for Microstructural Science of Materials, School of Materials Science and Engineering, Seoul National University, Seoul, 151–742, Korea
Young-Hag Koh
Affiliation:
Creative Research Center for Microstructural Science of Materials, School of Materials Science and Engineering, Seoul National University, Seoul, 151–742, Korea
Jong-Jin Choi
Affiliation:
Creative Research Center for Microstructural Science of Materials, School of Materials Science and Engineering, Seoul National University, Seoul, 151–742, Korea
Hyoun-Ee Kim
Affiliation:
Creative Research Center for Microstructural Science of Materials, School of Materials Science and Engineering, Seoul National University, Seoul, 151–742, Korea
Seung Su Baek
Affiliation:
Agency for Defense Development, Yuseong P.O. Box 35–4, Taejon, 305–600, Korea
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Abstract

Microstructural evolution and mechanical properties of gas-pressure-sintered Si3N4 with 4 wt% Yb2O3 as a sintering aid were investigated. The microstructure was not uniform throughout the specimen. Extremely large elongated grains were formed at the outer region near the surface, while relatively small elongated grains were formed at the inner region of the specimen. The outer region expanded inward with the sintering time. Mechanical properties, such as flexural strength, fracture toughness, and R-curve behavior of the specimens were strongly influenced by these variations in microstructure. The fracture toughness and the R-curve behavior of the outer region were higher than those of the inner region of the same specimen. On the other hand, the strength of the inner region was higher than that of the outer region. By controlling the relative thickness of each region, Si3N4 specimens having functionally graded microstructure were obtained. The Si3N4 with such microstructure exhibited high strength, high fracture toughness, and good flaw tolerance at the same time.

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Articles
Copyright
Copyright © Materials Research Society 1999

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References

REFERENCES

1.Mitomo, M., J. Am. Ceram. Soc. 75, 103 (1992).CrossRefGoogle Scholar
2.Sanders, W.A. and Mieskowski, D.M., Am. Ceram. Soc. Bull. 64, 304 (1985).Google Scholar
3.Hirosaki, N., Okada, A., and Matoba, K., J. Am. Ceram. Soc. 71, C144 (1988).CrossRefGoogle Scholar
4.Tani, E., Umebayashi, S., Kishi, K., Kobayashi, K., and Nishijima, M., Am. Ceram. Soc. Bull. 65, 1311 (1986).Google Scholar
5.Becher, P. F., Lin, H. T., Hwang, S. L., Hoffmann, M. J., and Chen, I-W., in Silicon Nitride Ceramics—Scientific and Technological Advances, edited by Chen, I-W., Becher, P. F., Mitomo, M., Petzow, G., and Yen, T-S. (Mater. Res. Soc. Symp. Proc. 287, Pittsburgh, PA, 1993), p. 147.Google Scholar
6.Becher, P. F., Hwang, S. L., Lin, H. T., and Tiegs, T. N., in Tailoring of Mechanical Properties of Si3N4 Ceramics, edited by Hoffmann, M. J. and Petzow, G. (Kluwer Academic Publishers, Dordrecht, The Netherlands, 1994), p. 87.CrossRefGoogle Scholar
7.Vetrano, J. S., Kleebe, H-J., Hampp, E., Hoffmann, M. J., Rühle, M., and Cannon, R. M., J. Mater. Sci. 28, 3529 (1993).CrossRefGoogle Scholar
8.Nishimura, T. and Mitomo, M., J. Mater. Res. 10, 240 (1995).CrossRefGoogle Scholar
9.Hoffmann, M. J., in Tailoring of Mechanical Properties of Si3N4 Ceramics, edited by Hoffmann, M.J. and Petzow, G. (Kluwer Academic Publishers, Dordrecht, The Netherlands, 1993), p. 233.Google Scholar
10.Wang, C-M., Pan, X., Hoffmann, M.J., Cannon, R.M., and Rühle, M., J. Am. Ceram. Soc. 79, 788 (1996).CrossRefGoogle Scholar
11.Park, H., Kim, H-E., and Niihara, K., J. Am. Ceram. Soc. 80, 750 (1997).CrossRefGoogle Scholar
12.Lee, W-H., Kim, H-E., and Cho, S-J., J. Am. Ceram. Soc. 80, 2737 (1997).CrossRefGoogle Scholar
13.Pyzik, A. J. and Beaman, D. R., J. Am. Ceram. Soc. 76, 2737 (1993).CrossRefGoogle Scholar
14.Sajgalik, P., Dusza, J., and Hoffmann, M. J., J. Am. Ceram. Soc. 78, 2619 (1995).CrossRefGoogle Scholar
15.Russo, C. J., Harmer, M. P., Chan, H. M., and Miller, G. A., J. Am. Ceram. Soc. 75, 3396 (1992).CrossRefGoogle Scholar
16.Harmer, M. P., Chan, H.M., and Miller, G. A., J. Am. Ceram. Soc. 75, 1715 (1992).CrossRefGoogle Scholar
17.Choi, B-J., Koh, Y-H., and Kim, H-E.J. Am. Ceram. Soc. 81, 2725 (1998).CrossRefGoogle Scholar
18.Chantikul, P., Anstis, G. R., Lawn, B. R., and Marshall, D. B., J. Am. Ceram. Soc. 64, 539 (1981).CrossRefGoogle Scholar
19.Krause, R. F. Jr, J. Am. Ceram. Soc. 71, 338 (1988).CrossRefGoogle Scholar
20.Lange, F. F., J. Am. Ceram. Soc. 65, C120 (1982).Google Scholar