48 Y. Miyashita et al. /International Journal of Fatigue 24(2002)241-248 300 damage mode whIc depended on the orientation of fiber bundles in of a notch and the extent of 0 (b)Independent of the type of damage mode, final failures occurred at an mOR which was about 85% of 只 the value of the mor 200 150 Shijie zhu is grateful for the Grant-in-Aid for Encour- Ministry of Education, Science, Sports and Culture, 100 Jar Q Initial MOR Maximum mor References Type 1 Type 2 [] Rouby D, Reynaud P. Fatigue behavior related to interface modi- fication during load cy y in ceramic-matrix fiber composites Fig. 11. Initial MOR, final MOR and maximum MOR for the speci- Compos Sci Technol 1993: 48: 109-18 2] Evans AG, Zok FW, McMeeking RM. Fatigue of ceramic matrix composites. Acta Metall Mater 1995: 43(3): 859-75 3] Reynaud P, Rouby D Fantozzi G, Abbe F and Peres P. Cyclic fatigue at high tempe Ires of ceramic-matrix composites. High performance. In Evans AG and Naslain R, editors. Ceramic 0 Transactions, vol. 57. Westerville(OH, USA): American Ceramic 这 14 Mizuno M, Zhu S, Nagano Y, Sakaida Y, Kagawa Y, Kaya H. Cyclic fatigue behavior of SiC/SiC composite at room and high temperatures. J Am Ceram Soc 1996, 79(12): 3065-77. 弓 [5]DiCarlo JA. Creep limitations of current polycrystalline ceramic fibers. Compos Sci Technol 1994: 51: 213-22 16] Morris WL, Cox BN, Marshall DB, Inman RV, James MR. Fatigue mechanisms in graphite/SiC composites at room and high [7 Zhu S, Kagawa Y, Mizuno M, Guo SQ, Nagano Y, Kaya H. In situ observation of cyclic fatigue crack propagation of SiC fiber/SiC composite at room temperature. Mater Sci Eng, A MOR -o-Fracture stres [8] Fox DS. Oxidation kinetics of enhanced SiC/SiC. Ceram Eng Sci Proc1995;16:877-84 [9 Zhu S, Mizuno M, Kagawa Y, Cao J, Nagano Y, Kaya H Creep Fig. 12. MOR reduction and fracture stress for the specimens tested and fatigue behavior of enhanced SiC/SiC composite at high tem- peratures. J Am Ceram Soc 1998: 81: 2269-77 [10 Karandikar PG, Chou T-W. Damage development and reductions in Nicalon-calcium aluminosilicate composite the notch tip but also at large pores remote from the static fatigue and cyclic fatigue. J Am Ceram notch. The observed widespread damage indicates that 1993:76:1720- a linear elastic fracture mechanics parameter cannot be [11] Zawada LP, Butkus LM, Hartman GA. Tensile and fatigue applied to describe the fatigue crack growth behavior of behavior of silicon carbide fiber-reinforced aluminosilicate glass SiC/SiC materials. Instead, the MOR may be used as a J Am Ceram Soc 1991: 74: 2851-8 parameter for estimating the fatigue damage proces [12] Shuler SF, Holmes JW, Wu X. Influence of loading frequency on the room-temperature fatigue of a carbon-fiber/SiC-matrix The crack behavior was divided into several types of composite. J Am Ceram Soc 1993, 76(9): 2327-36248 Y. Miyashita et al. / International Journal of Fatigue 24 (2002) 241–248 Fig. 11. Initial MOR, final MOR and maximum MOR for the speci￾mens tested. Fig. 12. MOR reduction and fracture stress for the specimens tested. the notch tip but also at large pores remote from the notch. The observed widespread damage indicates that a linear elastic fracture mechanics parameter cannot be applied to describe the fatigue crack growth behavior of SiC/SiC materials. Instead, the MOR may be used as a parameter for estimating the fatigue damage process. The crack behavior was divided into several types of damage modes which depended on the orientation of fiber bundles in front of a notch and the extent of matrix porosity. (b) Independent of the type of damage mode, final failures occurred at an MOR which was about 85% of the maximum value of the MOR. Acknowledgements Shijie Zhu is grateful for the Grant-in-Aid for Encour￾agement of Young Scientists (No. 09750105) by the Ministry of Education, Science, Sports and Culture, Japan. References [1] Rouby D, Reynaud P. Fatigue behavior related to interface modi- fication during load cycling in ceramic-matrix fiber composites. Compos Sci Technol 1993;48:109–18. [2] Evans AG, Zok FW, McMeeking RM. Fatigue of ceramic matrix composites. Acta Metall Mater 1995;43(3):859–75. [3] Reynaud P, Rouby D Fantozzi G, Abbe F and Peres P. Cyclic fatigue at high temperatures of ceramic-matrix composites. High￾temperature ceramic-matrix composites I: design, durability and performance. In Evans AG and Naslain R, editors. Ceramic Transactions, vol. 57. Westerville (OH, USA): American Ceramic Society, 1995:85–94. [4] Mizuno M, Zhu S, Nagano Y, Sakaida Y, Kagawa Y, Kaya H. Cyclic fatigue behavior of SiC/SiC composite at room and high temperatures. J Am Ceram Soc 1996;79(12):3065–77. [5] DiCarlo JA. Creep limitations of current polycrystalline ceramic fibers. Compos Sci Technol 1994;51:213–22. [6] Morris WL, Cox BN, Marshall DB, Inman RV, James MR. Fatigue mechanisms in graphite/SiC composites at room and high temperature. J Am Ceram Soc 1994;77(3):792–800. [7] Zhu S, Kagawa Y, Mizuno M, Guo SQ, Nagano Y, Kaya H. In situ observation of cyclic fatigue crack propagation of SiC- fiber/SiC composite at room temperature. Mater Sci Eng, A 1996;220:100–8. [8] Fox DS. Oxidation kinetics of enhanced SiC/SiC. Ceram Eng Sci Proc 1995;16:877–84. [9] Zhu S, Mizuno M, Kagawa Y, Cao J, Nagano Y, Kaya H. Creep and fatigue behavior of enhanced SiC/SiC composite at high tem￾peratures. J Am Ceram Soc 1998;81:2269–77. [10] Karandikar PG, Chou T-W. Damage development and moduli reductions in Nicalon-calcium aluminosilicate composites under static fatigue and cyclic fatigue. J Am Ceram Soc 1993;76:1720–8. [11] Zawada LP, Butkus LM, Hartman GA. Tensile and fatigue behavior of silicon carbide fiber-reinforced aluminosilicate glass. J Am Ceram Soc 1991;74:2851–8. [12] Shuler SF, Holmes JW, Wu X. Influence of loading frequency on the room-temperature fatigue of a carbon-fiber/SiC-matrix composite. J Am Ceram Soc 1993;76(9):2327–36