Improvement of the mechanical and thermophysical properties of C/SiC composites fabricated by liquid silicon infiltration

Two different matrices (silicon and Ti3SiC2) were introduced into two-dimensional woven C/SiC reinforced with T-300™ carbon fiber (40 vol.%) by liquid silicon infiltration, and their mechanical and thermophysical properties were studied compared with those of C/SiC fabricated by chemical vapor infiltration. C/SiC–Si shows higher tensile strength than C/SiC and C/SiC–Ti3SiC2 due to the existence of low thermal residual stress (TRS), while the low interlaminar shear strength and three-point bending strength of C/SiC–Si can be attributed to the brittleness of dense Si–SiC matrix. The introduction of Ti3SiC2 in a dense matrix can cause toughening mechanisms and inhibit the crack propagation by various micro-deformations of Ti3SiC2 grains. Therefore, C/SiC–Ti3SiC2 shows higher Young’s modulus, interlaminar shear strength and thermal conductivity than C/SiC and C/SiC–Si. The low tensile strength is due to the existence of high TRS in C/SiC–Ti3SiC2.