Influence of Grain Size Distribution on Hardness and Fracture Toughness of Si₃N₄/SiC Nanocomposites

Abstract:

Si3N4/SiC nanocomposite material with yttria as sintering additive was prepared by hot pressing method. SiC nanoinclusions were produced by in situ reaction between SiO2 and C during the sintering process. The homogenous microstructure of hot pressed samples contained fine Si3N4 grains with average diameter of 200 nm. The post-sintering treatment at 1750°C for 26 and 70 hours significantly changed the microstructure of Si3N4/SiC composites. The difference between the average grain size of hot pressed sample and sample treated for 70 hours is approx. 300 %. In sake of this fact the mechanical properties (KIC, HV1) were not changed significantly. The largest differences between the mechanical properties of hot pressed and annealed samples were only 8 %.

• Periodical: Advances in Science and Technology (Volume 45)
• Pages: 1680-1683
• DOI: https://doi.org/10.4028/www.scientific.net/AST.45.1680
• Online since: October 2006
• Authors: Miroslav Hnatko, Štefánia Lojanová, Helena Pálková, Zoltán Lenčéš, Pavol Šajgalík
• Keywords: Grain Size, Mechanical Property, Microstructure, Nanocomposite

References

[1] P.F. Becher: J. Am. Ceram. Soc. 74 (1991) 255.

[2] P.F. Becher, E.Y. Sun, K.P. Plucknett, K.B. Alexander, C. -H. Hsueh, H. -T. Lin, S.B. Waters, C.G. Westmoreland, E. -S. Kang, K. Hirao, M.E. Brito: J. Am. Ceram. Soc. 81 (1998) 2821.

[3] P. Šajgalík, J. Dusza, M.J. Hoffmann: J. Am. Ceram. Soc. 78.

[10] (1995) 2619.

[4] H. Imamura, K. Hirao, M.E. Brito, M. Toriyama, S. Kanzaki: J. Am. Ceram. Soc. 86.

[3] (2000) 495.

[5] X. Xu, T. Nishimura, N. Hirosaki, R.J. Xie, Y. Yamamoto: Key Eng. Mater. 287 (2005) 166.

[6] D.K. Shetty, I.G. Wright, P.M. Mincer, A.H. Clauer: J. Mater. Sci. 20 (1985) 1873.

[7] T. Kawashima, H. Okamoto, H. Yamamoto, A. Kitamura: J. Jpn. Ceram. Soc. 99.

[4] (1991) 320.