661715Ky 02115Ky沁:643 Fig 3. Microstructure of 3D Hi-Nicalon SiC/SiC composites. 268320KUx14810wmW03 220KU X330100 261328KV X221WD38 Fig 4. Fracture surface of 3D Hi-Hicalon fiber to be pulled out from the silicon carbide matrix. If CFCCs, the bundle/bundle interfacial bonding is the temperature was increased above the silicon carbide usually considered as a kind of weak interfacial bonding infiltration temperature (1100oC), a compressive stress because of the pores residual in the composites caused was created across the interfacial layer. Hence, the fiber by the"bottom neck effect"during the chemical vapor was very difficult to pull out. The pull-out length at infiltration process. Accordingly, fiber bundle pullout 600C was much shorter than at room temperature, as was a]ways observed at both room temperature and hown in Fig. 4a, b. For the three dimensional textile high temperature(Fig. 4c, d)fiber to be pulled out from the silicon carbide matrix. If the temperature was increased above the silicon carbide infiltration temperature (1100C), a compressive stress was created across the interfacial layer. Hence, the fiber was very difficult to pull out. The pull-out length at l300C was much shorter than at room temperature, as shown in Fig. 4a,b. For the three dimensional texti1e CFCCs, the bundle/bundle interfacial bonding is usually considered as a kind of weak interfacial bonding because of the pores residual in the composites caused by the ‘‘bottom neck effect’’ during the chemical vapor infiltration process. Accordingly, fiber bundle pullout was a]ways observed at both room temperature and high temperature (Fig. 4c,d). Fig. 3. Microstructure of 3D Hi-Nicalon SiC/SiC composites. Fig. 4. Fracture surface of 3D Hi-Hicalon SiC/SiC composites. Y. Xu et al. / Ceramics International 27 (2001) 565–570 567