Preparation and mechanical properties of C/C composites reinforced with arrayed SiC columnar pins

Abstract C/C composites with SiC columnar pins were fabricated by a recently developed space-holder method. Effects of SiC columnar pins with pins-row spacing of 5 mm and 4 mm on mechanical properties and toughening of C/C composites were characterized and discussed. Corresponding porous C/C composite matrices were also characterized. The results show that introduction of SiC columnar pins not only improves the compressive and shear properties of C/C composites, but significantly affects the PyC texture of the C/C composite matrix. Under identical TG-CVI deposition conditions, the pristine C/C composites (S0), the unidirectional porous C/C composites (S1 and S2), and the C/C composites with SiC columnar pins (S3 and S4) show typical low-textured PyC, high-textured PyC, and medium-textured PyC, respectively. The mechanical properties of unidirectional porous C/C composites with channels-row spacing of 5 mm (S1) are higher than those of unidirectional porous C/C composites with channels-row spacing of 4 mm (S2). Conversely, for the C/C composites with SiC columnar pins, the mechanical properties of samples with columns-row spacing of 5 mm (S3) are lower than those with columns-row spacing of 4 mm (S4). Moreover, the compressive strength P//(load direction parallel to the channel), P⊥ (load direction vertical to the channel), and shear strength of S3 and S4 is respectively higher than that of S1. Therefore, introduction of SiC columnar pins can effectively improve the mechanical properties of composites without significantly changing the density.