wwceramics. org/ACT Properties of Sic Matrix Composite 311 carbon fiber Sic fibe 150k13.0mm×500sE(M carbon fiber carbon fiber microcrack Fig. I. Scanning electron microscopic(SEM) images of polished cross-section morphologies of SiC matrix in three kinds of composites: (a) SiC matrix around carbon fiber bundle in sample A; (b) SiC matrix around SiC fiber bundle in sample A;(e) SiC matrix in sample B; and(d) SiC matrix in sample C. C(Fig. ld)had matrix microcracks. The TRS in the sample a decreased significantly. Compared with sam- ple B, the opening width of matrix microcracks in sam- ▲ Sample C le c decreased which indicated that the trs in sample C was lower than that in sample B. Mechanical Properties composites as a function of open porosity. As shown in Fig. 2, for samples A and C, when the porosity of the composites decreased from 15% and 16%to 6% and 9% he fexural strength increased from 385 and 359 MPa to 530 and 505 MPa. However, the fexural strength of sam ple b was nearly independent of the decrease of the Fig. 2. The flexural strength as a fuanction of the porosity for the porosity. As shown in Table Il, samples A, B, and C three kinds of composites.C (Fig. 1d) had matrix microcracks. The TRS in the sample A decreased significantly. Compared with sam￾ple B, the opening width of matrix microcracks in sam￾ple C decreased, which indicated that the TRS in sample C was lower than that in sample B. Mechanical Properties Figure 2 compares the flexural strength of the three composites as a function of open porosity. As shown in Fig. 2, for samples A and C, when the porosity of the composites decreased from 15% and 16% to 6% and 9%, the flexural strength increased from 385 and 359MPa to 530 and 505MPa. However, the flexural strength of sam￾ple B was nearly independent of the decrease of the porosity. As shown in Table II, samples A, B, and C SiC matrix a b c d carbon fiber SiC fiber SiC matrix microcrack carbon fiber microcrack carbon fiber Fig. 1. Scanning electron microscopic (SEM) images of polished cross-section morphologies of SiC matrix in three kinds of composites: (a) SiC matrix around carbon fiber bundle in sample A; (b) SiC matrix around SiC fiber bundle in sample A; (c) SiC matrix in sample B; and (d) SiC matrix in sample C. Fig. 2. The flexural strength as a function of the porosity for the three kinds of composites. www.ceramics.org/ACT Properties of SiC Matrix Composite 311