Abstract
Fatigue cracked and fast fractured regions in four-point bend specimens prepared from 25 wt% silicon carbide whisker reinforced alumina composite were examined by scanning electron microscopy. This composite was found to be susceptible to a fatigue crack growth phenomenon similar to that in the case of metallic materials, but with a higher crack growth exponent. In the fatigue region, the alumina matrix failed mainly in a transgranular mode and the whiskers mainly failed with a flat fracture surface but without their pullout. On the other hand, in the fast fracture region, the whiskers failed predominantly by pullout and the alumina matrix failed in a mixed mode with about half in transgranular and the other half in intergranular mode. Thus, to improve the fracture toughness of the material, the grain boundary strength of alumina and the matrix whisker interfacial bonding should be improved. To increase the resistance to fatigue, the fracture strength of the alumina grains should be improved by using finer α-alumina particles and the fatigue strength of the whisker have to be increased by improving the uniformity in distribution of β-SiC whiskers during hot pressing.
Similar content being viewed by others
References
Becher P F and Wei G C 1984J. Am. Ceram. Soc. 67 267
Brown W F Jr and Srawley J E 1966 ASTM-STP-410 (Philadelphia: ASTM)
Cook J L and Rhodes J R 198688th Annual meeting of the American Ceramic Society, Chicago, IL
Dauskardt R H, Porter J R and Ritchie R O 1992J. Am. Ceram. Soc. 75 759
Fisher E S, Manghnani M H and Routbort J L 1991Study of the elastic properties of Al 2O3 and Si3N4 material component, high performance composites for the 1990s (eds) S K Das, C P Ballard and F Marikar (The Minerals, Metals and Materials Society) p. 365
Ikuma Y and Virkar A V 1984J. Mater. Sci. 19 2223
Kingery W D, Bown H K and Uhlmann D R 1976Introduction of ceramics (New York: John Wiley and Sons, Inc.) 2nd ed. p. 795
Krause R F Jr and Fuller E R Jr 1990J. Am. Ceram. Soc. 73 559
Marshall D B and Lawn B R 1977J. Am. Ceram. Soc. 60 86
Ponton C B and Rawlings R D 1989Br. Ceram. Trans. J. 88 83
Ray A K and Banerjee S 1994J. Am. Ceram. Soc. (accepted)
Ray A K, Fuller E R and Banerjee S 1994J. Eur. Ceram. Soc. (accepted)
Ray A K, Mohanty G and Ghosh A 1991J. Mater. Sci. Lett. 10 227
Wei G C and Becher P F 1985J. Am. Ceram. Soc. Bull. 64 298
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Ray, A.K., Banerjee, S., Fuller, E.R. et al. Fractography as well as fatigue and fracture of 25 wt% silicon carbide whisker reinforced alumina ceramic composite. Bull. Mater. Sci. 17, 893–910 (1994). https://doi.org/10.1007/BF02757567
Issue Date:
DOI: https://doi.org/10.1007/BF02757567