Microstructures and Toughening Mechanisms of Y2O3 Doped Al2O3/ZrO2 Eutectic Composite Ceramics Prepared by SHS Melt-Growth Process


Article Preview

By introducing ZrO2(4Y) powder of suitable content into the thermit and based on oxidation-reduction reaction of the thermit and liquid-liquid phase separation of ceramics/metal under gravity, Al2O3/ZrO2(4Y) composite ceramics have been prepared through melt-growth with eutectic reaction under high degree of undercooling from SHS process. It has been found that the ceramics were composed of major rod-shaped sapphires with 8.0~12.0 aspect ratios and minor plate-like α-Al2O3 grains, and within the sapphires t-ZrO2 nano-micron fibers were embedded. Flexural strength and fracture toughness were measured to be 1256MPa and 13.2MPa·m1/2. It was obtained that a number of low energy interfaces (the interface distance on nano-micron scale) between two Al2O3/ZrO2 (4Y) phases and the strong compressive residual stress in the sapphires made the sapphires reinforced, forcing the crack to propagate along the rod-shaped sapphires; meanwhile, crack-bridging and pull-out of the sapphires, crack - bridging and frictionally interlocked effects of plate-like α-Al2O3 grains in the wake of crack tip also rendered the crack stabilization to arise.



Materials Science Forum (Volumes 546-549)

Edited by:

Yafang Han et al.




L. Zhang et al., "Microstructures and Toughening Mechanisms of Y2O3 Doped Al2O3/ZrO2 Eutectic Composite Ceramics Prepared by SHS Melt-Growth Process", Materials Science Forum, Vols. 546-549, pp. 1619-1622, 2007

Online since:

May 2007




[1] D. F. Becher: J. Am. Ceram. Soc. Vol. 74 (1991), p.255.

[2] J. P. Sing, D. Singh and M. Sutaria: Composite Part A Vol. 30 (1999), p.445.

[3] Y. Waku, H. Ohtsubo, N. Nakagawa and Y. Kohtoku: J. Mater. Sci. Vol. 31 (1996), p.4663.

[4] Y. Waku, N. Nakagawa, T. Wakamoto, H. Ohtsubo, K. Shimizu and Y. Kohtoku: Nature Vol. 389 (1997), p.49.

DOI: 10.1038/37937

[5] A. Sayir and S. C. Farmer: Acta Materialia Vol. 48 (2000), p.4691.

[6] J. H. Lee, A. Yoshikawa, H. Kaiden, K. Lebbou, T. Fukuda, D. H. Yoon and Y. Waku: Journal of Crystal Growth Vol. 231 (2001), p.179.

[7] Z. M. Zhao, L. Zhang, H. B. Bai and J. Zheng: Key Engineering Materials Vol. 280-283 (2005), p.1053.

[8] Z. M. Zhao, L. Zhang, J. Zheng and H. B. Bai: Scripta Materialia Vol. 53 (2005), p.995.

[9] J.H. Gong: Fracture Mechanics of Ceramics (Tsinghua University Press, China 2001).

[10] R. F. Cook: Acta Metall. Mater. Vol. 38 (1990), p.1083 Fig. 2 crack propagation paths Fig. 3 bridging and pull-out of Fig. 4 Vickers Indentation on the rod-shaped sapphires the ceramics.

Fetching data from Crossref.
This may take some time to load.