Compression and thermophysical properties of carbon fiber-reinforced high textured pyrocarbon and SiC dual matrix composites

C/C-SiC composites with high textured pyrocarbon (HT PyC) were fabricated by isothermal chemical vapor infiltration and reactive melt infiltration. The evolution of HT PyC before and after heat treatment at 2100 degrees C as well as the internal defects of the composites, such as pores and cracks, were characterized. The compression and thermophysical properties of the C/C-SiC composites with 2100 degrees C heat-treated HT PyC (C-S-21) and C/C composites with 2100 degrees C heat-treated HT PyC (C-C-21) were studied. The results showed that the compression strength and modulus of C-S-21 were 323.19 +/- 11.52 MPa and 4.49 +/- 0.13 GPa, which were increased by 58.94% and 125.63%, respectively, compared with those of C-C-21 owing to the smaller number of pores and the higher modulus of SiC and Si, respectively. However, fewer pores and strong interfacial adhesion resulted in the brittle fracture of C-S-21. The thermal conductivity of C-S-21 was 73.56 W/(m center dot K) and 44.94 W/(m center dot K) in the XY and Z directions, respectively, which was attributed to the fewer defects and better orientation of the graphitized layer in HT PyC as well as the smaller number of pores.