Enhanced densification and mechanical properties of carbon fiber reinforced silicon carbide matrix composites via laser machining aided chemical vapor infiltration

In this study, laser machining aided chemical vapor infiltration (LA-CVI) was developed to improve the density and mechanical properties of carbon fiber reinforced silicon carbide matrix (C/SiC) composites. Results showed that the density of C/SiC composites increased to 2.25 g cm⁻³ due to the generation of additional infiltration channels. Compressive strength and shear strength were improved by 50.7% and 11.8%, respectively, compared to those of classical CVI-C/SiC composites. Moreover, tensile strength showed similar value as that of classical CVI-C/SiC composites. These effects were attributed to re-opened infiltration channels which could provide more paths for precursor gases, thus promoting the densification in central region of composites. Furthermore, channels themselves were filled with SiC matrix and formed a dense SiC coating, which reflected convolution effects under uniaxial compression and exhibited damage-tolerant behavior under shear load.