G H. Min et al. /Ceramics International 29(2003)323-326 interlocking of delamination is attributed to the hetero- [2]D Kovar, B.H. King, J W. Holloran, Fibrous monolithic cera- geneous Sic interlayer [12]. During the middle and later mics, J. Am. Ceram Soc. 80(1997)2471 stages of the bending test, the interaction occurs among [3] R W. Trice J.W. Halloran, Influence of microstructure and tem- various propagating cracks, and the bridging is a domi erature on the interfacial fracture energy of silicon nitride/boron nant mechanism as in Fig. 4B. Finally, the sliding of nitride fibrous monolithic ceramics, J. Am. Ceram Soc. 82(1999) adjacent cells or/and cellular layers lasts a longer dis- [4] R.W. Trice, J.W. Halloran, Effect of sintering aid composition on placement at lower load-carrying. Thus, the fracture the processing of Si3N4/BN fibrous monolithic ceramics, J.Am behavior of the prismatic ceramics lies between multi Ceram.Soc.82(1999)2943 layered ceramics and fiber reinforced ceramic composites [ S.Y. Lienard, J.w.Halloran, Texture development of s nitride/boron nitride fibrous monolithic ceramics, J. Mater [6K. Ueno, Fabricating method for a prismatic ceramic compo- 4. Conclusion ites. JP Patent No 9-318910 [ K. Ueno, Prismatic structures ceramic, J. Soc. Mater. Sci. Japan By means of structure-controlled processing, pri [8 matic ceramic composites of the Al2O3/SiC system have mechanical properties of Si3 N4-based prismatic materials, in been prepared with a distinct prismatic texture of alu Proc. 16th Japan-Korea International Seminar on Ceramics mina-based cells, which are separated in three dimen 1999,pp.285-28 sions by thin Sic cell boundaries. 9J. She, T. Inoue, Mechanical properties and fracture behavior of The fracture toughness of the composites was AlO /SiC fibrous ceramics, J. Eur. Ceram Soc. 20(2000)1887 improved significantly. However, the bending strength [10 T. Inoue, K. Ueno, Mechanical properties and fracture beha- vior of SiTico fibre SiAlON composites, Ceram. Int. 24(1998) was decreased due to the reduced effective cross-section by weaker boundaries. When the thickness of Sic [l] s. Cai, Y. Huang, Infiuence of interface characteristic on the interphase is 9.3-15.6 um, a fracture work of 1221.4- echanical properties of multiplayer Si]N4 ceramics, Acta Com 81.6 J/m- was obtained with good combination of positie Sinica 16(1999)11( [2] J. She, T. Inoue, Fabrication and characterization of multiplayer bending strength and toughness umina-based composites with improved fracture behavi Generally, the composites fractured in a non-brittle Mater.Let.42(2000)155. manner. a crack deflecting and delimitating are con [3S. Baskaran, J. Holloran, Fibrous monolithic cer sidered as two main contributions for the improved mechanical properties and oxidation behavior of the silicon fracture energy, and frictional sliding of adjacent carbide/boron nitride system, J. Am. Ceram. Soc. 77(1994) rous ce lls becomes more dominant after cracking [14) J. She, T. Inoue, Fracture behavior and mechanical properties of occurs, especially at lower load condition. fracture char- acteristics of the prismatic ceramics lies between those of thickness, Mater. Sci. Lett. 19(2000)4 the multilayered ceramics and fiber reinforced ceramic [5] J. She, T. Inoue, Multilayered Al2O3/ SiC ceramics with composites due to three-dimensional controlled structure improved mechanical behavior, J. Eur. Ceram. Soc. 20(2000) [16 J. She, T. Inoue, Mechanical properties and fracture behavior of References AlO3 laminates with different architectures, Mater. Lett. 46 [S. Baskaran, S.D. Dunn, J.W. Holloran, Fibrous monolithic [17 G.H. Min, R. LiNon-catastrophic fracture of alumina-based ceramics: fabrication microstructure and indentation behavior. J. prismatic ceramic composites, Chinese J. Mater. Res. 15(16) Am. Ceran.Soc.76(1993)2209 2001)693-698interlocking of delamination is attributed to the hetero￾geneous SiC interlayer [12]. During the middle and later stages of the bending test, the interaction occurs among various propagating cracks, and the bridging is a domi￾nant mechanism as in Fig. 4B. Finally, the sliding of adjacent cells or/and cellular layers lasts a longer dis￾placement at lower load-carrying. Thus, the fracture behavior of the prismatic ceramics lies between multi￾layered ceramics and fiber reinforced ceramic composites. 4. Conclusion By means of structure-controlled processing, pris￾matic ceramic composites of the Al2O3/SiC system have been prepared with a distinct prismatic texture of alu￾mina-based cells, which are separated in three dimen￾sions by thin SiC cell boundaries. The fracture toughness of the composites was improved significantly. However, the bending strength was decreased due to the reduced effective cross-section by weaker boundaries. When the thickness of SiC interphase is 9.3–15.6 mm, a fracture work of 1221.4– 1481.6 J/m2 was obtained with good combination of bending strength and toughness. Generally, the composites fractured in a non-brittle manner, and crack deflecting and delimitating are con￾sidered as two main contributions for the improved fracture energy, and frictional sliding of adjacent fibrous cells becomes more dominant after cracking occurs, especially at lower load condition. Fracture char￾acteristics of the prismatic ceramics lies between those of the multilayered ceramics and fiber reinforced ceramic composites due to three-dimensional controlled structure. References [1] S. Baskaran, S.D. Dunn, J.W. Holloran, Fibrous monolithic ceramics: fabrication, microstructure and indentation behavior, J. Am. Ceram. 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