This article presents an analysis of the 27 wt.% SiC whisker/A1203 c01 posites exposed to air for periods up to 180 hours at 1100 C to 1450 C. Experimental results indicate that SiC whisker reacts with oxygen and alumina to produce a mullite-rich surface layer on tested composite specimens. The surface oxidation reaction degrades the observed elastic moduli of specimens. A theoretical analysis based on the Bernoulli-Euler beam equation shows that the surface layer has lower elastic modulus than the unreacted core.
Get full access to this article
View all access options for this article.
References
1.
1. Becher. P. F.. C. H. Hsueh, P. Angelini and T. N. Tiegs. 1988. "Toughening Behavior in Whisker-Reinforced Ceramic Matrix Composites,"J. Ani. Ceram. Soc.. 71(12):1050-1061.
2.
2. Campbell. G. H., M. Ruhle, B. J. Dalgleish and A. G. Evans. 1990. "Whisker Toughening: A Comparison between Aluminium Oxide and Silicon Nitride Toughened with Silicon Carbide,"J. Ami. Ceram. Soc.. 73(3):521-530.
3.
3. Sykes. M. T., R. O. Scattergood and J. L. Routbort. 1987. "Erosion of SiC-Reinforced Alumina Ceramic Composites,"Composites, 18(2):153-163.
4.
4. Govila. R. K.1988. "Fracture of Hot-Pressed Alumina and SiC-Whisker-Reinforced Alumina Composite,"J. Mater. Sci., 23:3782-3791.
5.
5. Becher, P. F., P. Angelini, W. H. Warwick and T. N. Tiegs. 1990. "Elevated-Temperature Delayed Failure of Alumina Reinforced with 20 Vol% Silicon Carbide Whiskers,"J. Aoti. Ceram. Soc.. 73(1):91-96.
6.
6. Jahus. K. and S. V. Nail. 1990. "Nucleation and Growth of Cracks in SiC/A1203 Composites,". Composites Sci. and Tech., 37:279-297.
7.
7. Tiegs. T. and P. F. Becher. 1987. "Thermal Shock Behavior of an Alumina-SiC Whisker Composite,"J. Alit. Cerami. Soc., 70(5):Cl09-C111.
8.
8. Whitehead, A. J. and T. F. Page. 1989. "Degradation of SiC Whiskers at Elevated Temperature,". Ceram. Eng. Sci. Proc.. 10(7-8):986-997.
9.
9. Maeda, M., K. Nahamura and T. Ohkubo. 1988. "Oxidation of Silicon Carbide in a Wet Atmosphere"J. Mater. Sci.. 23:3933-3938.
10.
10. Costello, J. A. and R. E. Tressler. 1981. "Oxidation Kinetics of Hot-Pressed and Sintered a-SiC."J. Ami. Cerami. Soc.. 64(6):327-331.
11.
11. Forthmann, R. and A. Naoumidis. 1989. "Hot-Gas Corrosion of Silicon Carbide Materials at Temperatures between 1200 and 1400°C,"Mater. Sci. and Eng., A121:457-460.
12.
12. Singhal, S. C.1976. "Oxidation Kinetics of Hot-Pressed Silicon Carbide,"J. Mater. ScI.,"11:1246-1253.
13.
13. Lange, F. F.1975. "Hot-Pressing Behavior of Silicon Carbide Powders with Additions of Aluminium Oxide,"J. Mater. Sci., 10:314-320.
14.
14. Singhal, S. C. and F. F. Lange. 1975. "Effect of Alumina Content on the Oxidation of HotPressing Silicon Carbide,"J. Am. Ceram. Soc., 58(9-10):433-435.
15.
15. Borom, M. P., M. K. Brun and L. E. Szaia. 1987. "Kinetics of Oxidation of Carbide and Silicide Dispersed Phase in Oxide Matrices,"Ceram. Elng. Sci. Proc., 8(7-8):654-670.
16.
16. Lin, F., T. Marieb, A. Morrone and S. Nutt. 1988. "Thermal Oxidation of A1203-SiC Whisker Composites: Mechanisms and Kinetics," in High Temperature/High Performance Composites. Materials Research Society Proc., Pittsburgh, PA, MRS, 120:271-278.
17.
17. Luthra, K. L. and H. D. Park. 1990. "Oxidation of Silicon-Reinforced Oxide-Matrix Composites at 1375° to 1575°C,"J. Am. Ceram. Soc.. 73(4):1014-1023.
18.
18. Chiu, C. C.1990. "Determination of the Elastic Modulus and Residual Stresses in Ceramic Coatings Using a Strain Gage,"J. Am. Ceram. Soc., 73(7):1999-2005.
19.
19. Chiu, C. C. and E. D. Case. 1991. "Elastic Modulus Determination of Coating Layers as Applied to Layered Ceramic Composites,"Mater Sci. and Eng., A132:39-47.
20.
20. Chen, W T. and P. A. Engel. 1972. "Impact and Contact Stress Analysis in Multilaver Media. Int. J. Solids Structures, 8(11):1257-1281.
21.
21. Reapproved 1981. "Standard Test Method for Young's Modulus, Shear Modulus, and Poisson's Ratio for Glass and Glass-Ceramics by Resonance,"Annual Book of ASTM Standard, Designation: C623-71.
22.
22. Anstis, G. R., P. Chantikul, B. R. Lawn and D. B. Marshall. 1981. 'A Critical Evaluation of lndentation Techniques for Measuring Fracture Toughness: 1. Direct Crack Measurenients'J. Am. Ceram. Soc., 64(9):533-538.
23.
23. Gulbransen, E. A. and S. A. Jansson. 1972. "The High-Temperature Oxidation, Reaction. and Volatilization Reaction of Silicon and Silicon Carbide,"Ovsidation of Metals, 4(3):181-201.
24.
24. Kingery, W. D., H. K. Bowen and D. R. Uhlmann. 1976. Introduction IO Ctoifamcs. New York: John Wiley & Sons Inc., pp. 381-395.
25.
25. Rothman, S. J.1984. Diffusion in Crystalline Solids. G. E. Murch and A. S. Nowick. eds.. New York: Academic Press Inc., pp. 1-15.
26.
26. Jost, W.1960. Diffusion. New York: Academic Press, pp. 350-362.
27.
27. Gaskell, D.1973. Introduction to Metallurgical Therntodvnaiocs. TN: Scripta Publishing Company, p. 497-497.
28.
28. Smithells, C. J.1949. Metals Reference Book. New York: Interscience Publisher Inc., p. 482-482.
29.
29. Volterra, E. and E. C. Zachmanoglou. 1965. Dvnainic.s of Vibrations. Columbus, OH: Charles E. Merrill Books Inc., p. 321-321.
