S Guo, Y. Kagawa/Journal of the European Ceramic Society 22(2002)2349-2356 2. For the Hi-Nicalon/ BN/SiC, tensile strength and at elevated temperatures. J. Am. Ceram Soc., 1995. 78(2), 388- strain to failure increased slightly with increasing 394 test temperature from 298 to 1200 K and then 10. Rice. R. W Treatise on Materials Science and Technology, vol decreased at 1400 K, while Youngs modulus Il, p. 199. Academic Press, New York, 1978 I1. Thouless, M. D. and Evans. A. G. Effects of pullout on the decreased with increasing test temperature. A echanical properties of cera matrIx noncatastrophic fracture was observed for all the Metall,1988,36.517-522 test temperature 12. Heredia, F. E, Spearing, S. M. Evans, A. G, Mosher, P and 3. In situ constituent properties of both composites Curtin, W.A. Mechanical properties of continuous.fiber-rein- were determined by tensile stress-strain curves forced carbon matrix composites and relationship to constituent properties. J. A. Ceram Soc., 1992. 75(11), 3017-302 and fracture surface measurements. The con- 3. Takeda. M. Sakamoto. J. Saeki. A. and Ichikawa. H. Mechan. stituent properties of Hi-Nicalon/BN/SiC were ical and structural analysis of silicon carbide fiber Hi-nicalon type superior to those of Nicalon/C/SiC, especially at S. Ceram. Eng. Sci. Proc., 1996. 17(4-5), 35-42. ≥1200K Thouless. M. D. Sbaizero. O. Sigl. L. S. and Evans. A. G 4. The tensile strengths of the Hi-Nicalon/BN/SiC Effect of interface mechanical properties on pullout in a Sic- fiber-reinforced lithium aluminum silicate glass-ceramic. J.Amm. were governed by the fibers and could be pre- Ceran.Soc.,1989,72(4),525-532. dicted using fiber bundle model on base of in situ 15. Weibull, W, A statistical distribution function of wide applic- fiber strength. On the contrary, the fracture of ability. J. Appl. Mech,19518.293-298 the Nicalon/ C/SiC was not be dominated by the 16. Thouless, M. D. and Evans, A. G. Effect of pull-out on the fiber bundle, with weakest link failure mode echanical properties of ceramic matrix composites. Acta Metall,1988,36,517-522 17. Beyerle, D. S, Spearing, S M, Zok, F. w. and Evans. A. G, Damage and failure in unidirectional ceramic-matrix composites. Acknowledgements J.Am. Ceran.Soc.,l992,75,27192725 18. Singh.R.N. Influence of interface shear stress on first-matrix The authors thank mr Fujikura and cracking stress in ceramic-matrix composites. J. Am. Ceram. Soc. Tanaka, Ultra-High Temperature Materials Research Center Co, Ltd, Japan, for their help in the tensile test. Marshall. d. B. and brennan. J. J. Effect of interfaces on the The first author(SQ G. would also like to thank the properties of fiber-reinforced ceramics. J. Am. Ceram. Soc., 1990 Japan Society for the Promotion of Science 73(6).1691-169 financial support of his research in Japan car. P. G. an noduli reductions in nicalon-CAs composites under static fat ue and cyclic fatigue. J. Am. Ceram. Soc., 1993, 73, 1720-1728 21. Kim.R.Y and Pagano, N.J. Crack initiation in unidirectional References rittle-matrix composites J. Am. Ceram. Soc., 1991, 74(5), 1082- 1. Morscher, G. N, Tensile stress rupture of SiCe/SiCm mini- 22. Llorca, J, Elices, M. and Celemin, J. A, Toughness and micro- composites with carbon and boron nitride interphases at elevated ructural degradation at high temperature in SiC fiber-reinforced temperatures in air.J.Am. Ceram Soc., 1997, 80(8). 2029-2042. ceramics. Acta Mater. 1998, 46(7). 2441-2453. 2. Lipetzky, P, Dvorak, G.J. and Stoloff, N.S., Tensile properties 23. Ogbuji, L U.J. T, A pervasive mode of oxidative degradation in a of a SiCSiC composite. Mater. Sci. Eng, 1996, A216, 11-19. Sic-SiC composite, 1998, 81(11). 2777-2784 3. Singh, D, Singh, J. P and Wheeler. M. J, Mechanical behavior 24. Clark, T.J., Arons, R. M. and Stamatoff, J. B, Thermal degra- of Sic(f/SiC composites and correlation to in situ fiber strength dation of nicalon SiC fibers. Cera. Eng. Sci. Proc., 1985. 6(7-8). at room and elevated temperatures. J. Am. Ceram. Soc., 1996. 576-588 793),591-596 K. C, Hodder. R. S and Tressler, R. E, 4. Shin, D. w. and Tanaka, T, Low-temperature processing of Strengths of fibers at elevated temperatures. J. Am 2),284-288 Soc.,1994,77(1),97-104 26. Hollon, G, Pailler, R, Naslain, R. and Olry, P. composite mposition and mechanical behavior at high temperat ygen-free Hi-Nicalon fiber. In High-Temperature re of uhe latrix Composites I1, Vol 58. ed. A. G. Evans and R. Naslain. J. Am. Ceram. Soc., 1999, 82(6). 1579- Ceram. Trans., The American Ceramic Society, 1995, pp. 299- 6. Lissart, N. and Lamon, J, Damage and failure in ceramic matrix minicomposites: experimental study and model. Acta Mater, 27. Coleman, B. D, On the strength of classical fibers, fiberbundles 1997,45(3),1025-10 Mech. Phys. Solids. 1958.7.60-70 properties of ceramic. 28. Naslain. R, Dugne, O, Guette, A, Sevely, J, Robin-Brosse, C, matrix composites. J.Am. Ceram Soc., 1991, 74(11), 2837-28 Rocher, J. P and Cotteret, J, Boron nitride interphase in ceramic 8. Steyer, T. E, Zok, F. w. and Wall, D. P, Stress rupture of an matrix composites. J. Am. Ceram. Soc., 1991, 740(10), 2482-2488 chanced nicalon/ silicon carbide composite at intermediate tem- : 9. Prouhet. S. Camus, G, Labrugere. C, Guette, A. and Martin peratures.J.Am. Ceram. (8),2140-2146 E, Mechanical characterization of Si-C(O) fiber/SiC (CVn 9. Xu. H. H.K. Braun, L. M., Ostertag. C. P, Krause. R. F. and matrix composites with a BN-interphase J. Am. Ceram. Soc Lloyd, l.K. Failure modes of SiC-fiber/Si, Na matrix composites 1994,77(3),649-6562. For the Hi-Nicalon/BN/SiC, tensile strength and strain to failure increased slightly with increasing test temperature from 298 to 1200 Kand then decreased at 1400 K, while Young’s modulus decreased with increasing test temperature. A noncatastrophic fracture was observed for all the test temperatures. 3. In situ constituent properties of both composites were determined by tensile stress-strain curves and fracture surface measurements. The con￾stituent properties of Hi-Nicalon/BN/SiC were superior to those of Nicalon/C/SiC, especially at 51200 K. 4. The tensile strengths of the Hi-Nicalon/BN/SiC were governed by the fibers and could be pre￾dicted using fiber bundle model on base of in situ fiber strength. On the contrary, the fracture of the Nicalon/C/SiC was not be dominated by the fiber bundle, with weakest link failure mode. Acknowledgements The authors thank Mr. M. Fujikura and Dr. R. Tanaka, Ultra-High Temperature Materials Research Center Co., Ltd., Japan, for their help in the tensile test. The first author (S.Q.G.) would also like to thank the Japan Society for the Promotion of Science for its financial support of his research in Japan. References 1. Morscher, G. N., Tensile stress rupture of SiCf/SiCm mini￾composites with carbon and boron nitride interphases at elevated temperatures in air. J. Am. Ceram. Soc., 1997, 80(8), 2029–2042. 2. Lipetzky, P., Dvorak, G. J. and Stoloff, N. S., Tensile properties of a SiCf/SiC composite. Mater. Sci. Eng., 1996, A216, 11–19. 3. Singh, D., Singh, J. P. and Wheeler, M. J., Mechanical behavior of SiC(f)/SiC composites and correlation to in situ fiber strength at room and elevated temperatures. J. Am. Ceram. Soc., 1996, 79(3), 591–596. 4. Shin, D. W. and Tanaka, T., Low-temperature processing of ceramic woven fabric/ceramic matrix composites. J. Am. Ceram. Soc., 1994, 77(1), 97–104. 5. Takeda, M., Kagawa, Y., Mitsuno, S., Imai, Y. and Ichikawa, H., Strength of Hi-NicalonTM/silicon-carbide-matrix composite fabricated by the multiple polymer infiltration-pyrolysis process. J. Am. Ceram. Soc., 1999, 82(6), 1579–1581. 6. Lissart, N. and Lamon, J., Damage and failure in ceramic matrix minicomposites: experimental study and model. Acta Mater., 1997, 45(3), 1025–1044. 7. Curtin, W. A., Theory of mechanical properties of ceramic￾matrix composites. J. Am. Ceram. Soc., 1991, 74(11), 2837–2845. 8. Steyer, T. E., Zok, F. W. and Wall, D. P., Stress rupture of an enhanced nicalon/silicon carbide composite at intermediate tem￾peratures. J. Am. Ceram. Soc., 1998, 81(8), 2140–2146. 9. Xu, H. H. K., Braun, L. M., Ostertag, C. P., Krause, R. F. and Lloyd, I. K., Failure modes of SiC-fiber/Si3N4-matrix composites at elevated temperatures. J. Am. Ceram. Soc., 1995, 78(2), 388– 394. 10. Rice, R. W., Treatise on Materials Science and Technology, Vol. II, p. 199. Academic Press, New York, 1978. 11. Thouless, M. D. and Evans, A. G., Effects of pullout on the mechanical properties of ceramic matrix composites. Acta Metall., 1988, 36, 517–522. 12. Heredia, F. E., Spearing, S. M., Evans, A. G., Mosher, P. and Curtin, W. A., Mechanical properties of continuous-fiber-rein￾forced carbon matrix composites and relationship to constituent properties. J. Am. Ceram. Soc., 1992, 75(11), 3017–3025. 13. Takeda, M., Sakamoto, J., Saeki, A. and Ichikawa, H., Mechan￾ical and structural analysis of silicon carbide fiber Hi-nicalon type S. Ceram. Eng. Sci. Proc., 1996, 17(4–5), 35–42. 14. Thouless, M. D., Sbaizero, O., Sigl, L. S. and Evans, A. G., Effect of interface mechanical properties on pullout in a SiC- fiber-reinforced lithium aluminum silicate glass-ceramic. J. Am. Ceram. Soc., 1989, 72(4), 525–532. 15. Weibull, W., A statistical distribution function of wide applic￾ability. J. Appl. Mech., 1951, 18, 293–298. 16. Thouless, M. D. and Evans, A. G., Effect of pull-out on the mechanical properties of ceramic matrix composites. Acta Metall., 1988, 36, 517–522. 17. Beyerle, D. S., Spearing, S. M., Zok, F. W. and Evans, A. G., Damage and failure in unidirectional ceramic-matrix composites. J. Am. Ceram. Soc., 1992, 75, 2719–2725. 18. Singh, R. N., Influence of interface shear stress on first-matrix cracking stress in ceramic-matrix composites. J. Am. Ceram. Soc., 1990, 73(10), 2930–2937. 19. Cao, H. C., Bischoff, E., Sbaizero, O., Ruhle, M., Evans, A. G., Marshall, D. B. and Brennan, J. J., Effect of interfaces on the properties of fiber-reinforced ceramics. J. Am. Ceram. Soc., 1990, 73(6), 1691–1699. 20. Karandikar, P. G. and Chou, T. W., Damage development and moduli reductions in nicalon-CAS composites under static fati￾gue and cyclic fatigue. J. Am. Ceram. Soc., 1993, 73, 1720–1728. 21. Kim, R. Y. and Pagano, N. J., Crack initiation in unidirectional brittle-matrix composites. J. Am. Ceram. Soc., 1991, 74(5), 1082– 1090. 22. Llorca, J., Elices, M. and Celemin, J. A., Toughness and micro￾structural degradation at high temperature in SiC fiber-reinforced ceramics. Acta Mater., 1998, 46(7), 2441–2453. 23. Ogbuji, L. U. J. T., A pervasive mode of oxidative degradation in a SiC–SiC composite, 1998, 81(11), 2777–2784. 24. Clark, T. J., Arons, R. M. and Stamatoff, J. B., Thermal degra￾dation of nicalon SiC fibers. Ceram. Eng. Sci. Proc., 1985, 6(7–8), 576–588. 25. Pysher, D. J., Goretta, K. C., Hodder, R. S. and Tressler, R. E., Strengths of ceramic fibers at elevated temperatures. J. Am. Ceram. Soc., 1989, 72(2), 284–288. 26. Chollon, G., Pailler, R., Naslain, R. and Olry, P., Structure, composition and mechanical behavior at high temperature of the oxygen-free Hi-Nicalon fiber. In High-Temperature Ceramic￾Matrix Composites II, Vol. 58. ed. A. G. Evans and R. Naslain. Ceram. Trans., The American Ceramic Society, 1995, pp. 299– 304. 27. Coleman, B. D., On the strength of classical fibers, fiberbundles. J. Mech. Phys. Solids, 1958, 7, 60–70. 28. Naslain, R., Dugne, O., Guette, A., Sevely, J., Robin-Brosse, C., Rocher, J. P. and Cotteret, J., Boron nitride interphase in ceramic matrix composites. J. Am. Ceram. Soc., 1991, 74(10), 2482–2488. 29. Prouhet, S., Camus, G., Labrugere, C., Guette, A. and Martin, E., Mechanical characterization of Si-C(O) fiber/SiC (CVI) matrix composites with a BN-interphase. J. Am. Ceram. Soc., 1994, 77(3), 649–656. 2356 S. Guo, Y. Kagawa / Journal of the European Ceramic Society 22 (2002) 2349–2356