Modification and toughening of 3D needled C/SiC composite by deformable MAX phase-based matrix

3D needled (3DN) C/SiC fabricated through CVI has promising mechanical properties, though the low fiber content in the short-cut fiber layer results in large pores, which is hard to be filled and influences its mechanical properties. To solve this problem, this paper focuses on short-cut fiber layer of 3DN C/SiC preform and in-situ formation of MAX phase-based matrix with a joint process of slurry impregnation (SI) and reactive melt infiltration (RMI). The ratio of MAX phase to brittle phases in the matrix is adjusted through controlling the fabrication process. With the increase of MAX phase content, the advantages of the “strong” MAX phase with weak interface gradually emerge. The modification of MAX phase not only enriches toughening mechanism, but also elevates the bearing structure of 3DN C/SiC from one strong ply sandwiching three weak plies into three strong plies sandwiching one weak ply. Finally, 3DN C/SiC containing 15 vol.% Ti₃Si(Al)C₂ showed excellent mechanical properties, with flexural strength and fracture toughness up to 440 ± 17 MPa and 15.9 ± 1.4 MPa·m^1/2, respectively.