13th International Conference on Fracture June 16–21, 2013, Beijing, China 3 Interlaminar shear failure was conducted in a region between two notches that were asymmetrically located on opposite sides of the specimens at an equal distance from the mid-plane, as shown in Fig.2. A layer of SiC coating was deposited on the specimens after the machining of notches, and the thickness of coating was added to specimen dimension. It’s worth noting that both the warp loading direction and weft loading direction of the specimens for 2.5D-C/SiC were fabricated respectively. 2.2 Mechanical property measurement All tests were performed at 1173K in air. The specimens were heated at a rate of 40–50K/min, followed by a soaking period of 10 min after reaching the test temperature. Then the DNS specimens were applied to a compression load along the specimen axis, as shown in Fig. 2. Monotonic loading was carried out in displacement control at a rate of 0.595 mm/min. Five specimens were tested for each kind of ceramic matrix composites. The ILSS is calculated as Eq. 1: ILSS=Pmax/WL (1) Where Pmax is the ultimate compressive load, W is the specimen width and L is the notch spacing between the inner franks of the notches. Figure 2.Geometry and dimensions of the DNS specimen materials reinforcement preforms fiber volume fractions (%) Bulk density ( g/cm3) residual porosity(%) 2D-C/SiC 3K-PAN carbon fibers 2D 40 1.99 15 2.5D-C/SiC 3K-PAN carbon fibers 2.5D 45 2.05 15 2D-SiC/SiC 0.25K silicon carbide fibers 2D 40 2.61 11.5 (open porosity) Table 1. The parameters of tested composites
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