J. Ma et al. Materials Letters 61(2007)312-315 Table 4 composites developed can well meet the demands of the nose cap Shear test data of the composites i.e. the easiness of near-net shaping and the capability of with- ane shear strength(MPa) Interlaminar shear steer standing multidirectional mechanical and thermal stresses tion77(82) Standard deviations are given in parentheses The authors acknowledge the financial support of the Natural Science Foundation of China(Contract No. 90405015)and the which is ascribed to the intrinsic through-the-thickness reinforcements National Young Elitists Foundation( Contract No 50425208) of the fiber preforms References 4. Conclusion [ w.C. Chang, N.H. Tai, CC M. Ma, J Mater. Sci. 30(1995)1225 C/SiC composites reinforced with multilayer preforms were 2)CCM Ma, N.H. Tai, W.C. Chang. Y P. Tsal, Carbon 34(1996)1175 fabricated by isothermal chemical vapor infiltration (CvD) [4].A Naik, NASA Contract. Rep. 194930(1994) process. Their mechanical behavior under tension, bending and [5] Dr.-Ing Hermann Hald, Dipl.- Ing Hendrik Weihs, Dipl-Ing Thomas Reime shear loads exhibited great anisotropy, which was attributed to the DipL.-Min Thomas Ullmann. AIAA 2003-2696. differences in path and density between warp and weft yams. Due [6] Y.D. Xu, L.T. Zhang, L.E. Cheng, D. Yan, Carbon 36(1998)1051 to the intrinsic through-the-thickness reinforcements of the fiber [7] B Step preforms, the composites displayed higher interlaminar she [8] w. Krenkel, Ceram. Eng. Sci. Proc. 24 (4)(2003)583 properties compared to their 2D counterparts. Therefore, thewhich is ascribed to the intrinsic through-the-thickness reinforcements of the fiber preforms. 4. Conclusion C/SiC composites reinforced with multilayer preforms were fabricated by isothermal chemical vapor infiltration (ICVI) process. Their mechanical behavior under tension, bending and shear loads exhibited great anisotropy, which was attributed to the differences in path and density between warp and weft yarns. Due to the intrinsic through-the-thickness reinforcements of the fiber preforms, the composites displayed higher interlaminar shear properties compared to their 2D counterparts. Therefore, the composites developed can well meet the demands of the nose cap, i.e. the easiness of near-net shaping and the capability of with￾standing multidirectional mechanical and thermal stresses. Acknowledgements The authors acknowledge the financial support of the Natural Science Foundation of China (Contract No. 90405015) and the National Young Elitists Foundation (Contract No. 50425208). References [1] W.C. Chang, N.H. Tai, C.C.M. Ma, J. Mater. Sci. 30 (1995) 1225. [2] C.C.M. Ma, N.H. Tai, W.C. Chang, Y.P. Tsai, Carbon 34 (1996) 1175. [3] A. Dasgupta, R.K. Agarwal, J. Compos. Mater. 26 (1992) 2736. [4] R.A. Naik, NASA Contract. Rep. 194930 (1994). [5] Dr.-Ing Hermann Hald, Dipl.-Ing Hendrik Weihs, Dipl.-Ing Thomas Reimer, Dipl.-Min Thomas Ullmann. AIAA 2003–2696. [6] Y.D. Xu, L.T. Zhang, L.F. Cheng, D. Yan, Carbon 36 (1998) 1051. [7] B. Stephane, Compos. Sci. Technol. 61 (2001) 2285. [8] W. Krenkel, Ceram. Eng. Sci. Proc. 24 (4) (2003) 583. Table 4 Shear test data of the composites Specimen In-plane shear strength (MPa) Interlaminar shear strength (MPa) Warp direction 77 (8.2) 62 (3.7) Weft direction 81 (7.1) 27 (3.1) Standard deviations are given in parentheses. J. Ma et al. / Materials Letters 61 (2007) 312–315 315