Toughness Characterization of SiC/h-BN Ceramic Composites Prepared by PAS Sintering Process
YANG Wanli1, DAI Lina1, FAN Zhenning1, ZHANG Hanchen1, SHI Zhongqi2
1 Chaoma Technology Co. Ltd, Xi'an Aerospace Composites Research Institute, Xi'an 710025 2 School of Material Science and Engineering, Xi'an Jiaotong University, Xi'an 710049
Abstract: In order to investigate the failure characteristics of SiC/h-BN ceramic composites prepared by the plasma activated sintering (PAS) process, three kinds of toughness characterization methods (fracture toughness KIC, toughness ratio and R curve) were used as the basis to toughness for failure judgment of these composites. The microstructure of crack extension was also analyzed and discussed, and the failure model of the composites was established. The results show that both KIC was decreased with the h-BN content increase for the composites. The toughness ratio (TI) increased with the increasing h-BN content indicating the better toughness. Combined with the result of R curves, the composite with more h-BN content exhibited steeper rise R curve tendency, which had a lower crack extension threshold. So, there is a contradiction between the three kinds of toughness results. Based on the microstructure analysis, the h-BN plates existing in the composites could consume more fracture surface energy, and the cracks deflection, branching and bridging were occurred during cracks extension. Hence, KIC as the toughness index reflected the resistance of crack initiation, and TI indicating the crack extension resistance. To guide the application and failure evaluation of these ceramic composites, proper parameter should be used to characterize toughness under the different stress state of materials in engineering application.
1 Eichler J, Lesniak C. Journal of the European Ceramic Society, 2008, 28, 1105. 2 Wang X D, Qiao G J, Jin Z H. Journal of the American Ceramic Society, 2004, 87, 565. 3 Kishan R N, Mulay V, Jaleel M. Journal of Materials Science Letters, 1994, 13, 1516. 4 Roulet F, Tristant P, Desmaison J, et al. Journal of the European Ceramic Society, 1997, 17, 1877. 5 Jones M I, Etzion R, Metson J, et al. Journal of the Ceramic Society of Japan, 2008, 116, 712. 6 Yan M, Fan Z. Journal of Materials Science, 2001, 36, 285. 7 Hu Y W, Si W J, Gong J H. Rare Metal Materials and Engineering, 2011(S1), 156(in Chinese). 胡一文, 司文捷, 龚江宏.稀有金属材料与工程, 2011(S1), 156. 8 Lysiak G. Journal of Food Engineering, 2007, 83, 436. 9 Yang W L, Kang W J, Zhang Y H, et al. Journal of Solid Rocket Technology, 2016, 39(5), 692(in Chinese). 杨万利, 康文杰, 张永辉 等.固体火箭技术, 2016, 39(5), 692. 10 Kovar D, Bennison S J, Readey M J. Acta Materialia, 2000, 48, 565. 11 Qiao G J, Wang Y L, Jin Z H, et al. Journal of the Chinese Ceramic Society, 1996, 24(4), 400(in Chinese). 乔冠军, 王永兰, 金志浩, 等.硅酸盐学报, 1996, 24(4), 400. 12 Anstis G R, Chantikul P, Lawn B R, et al. Journal of the American Ceramic Society, 1981, 64, 533. 13 Chantikul P, Anstis G R, Lawn B R, et al. Journal of the American Ceramic Society, 1981, 64, 539. 14 Li D Y, Qiao G J, Jin Z H. Ceramics International, 2004, 30, 213. 15 Ramachandran N, Shetty D K. Journal of the American Ceramic Society, 1991, 74, 2634. 16 Ralph F, Krause Jr. Journal of the American Ceramic Society, 1988, 71, 338. 17 Wang X D, Qiao G J, Jin Z H. Journal of the American Ceramic Society, 2004, 87, 565. 18 Shi Z Q, Wang J P, Qiao G J, et al. Materials Science and Engineering A, 2008, 492, 29.