Preparation and Tensile Behavior of Mini SiC_f/SiC Composites with PyC-SiC Codeposition Interface

With third-generation domestic silicon carbide fiber (SiC_f) as reinforcement, pyrocarbon (PyC) and SiC codeposition interface layer were simultaneously deposited on the surface of SiC_f by chemical vapor infiltration (CVI) with deposition time of 20-70 min. Then SiC was deposited continueously and dense Mini SiC_f/SiC composites were prepared. The interface structure and teasile behavier of the composites were studied. The results show that the average thicknesses of the codeposition interface layer were 500, 1 100, 2 100 nm after deposition for 20, 40, 70 min, respectively, and the thickness of the interface layer was uniform; the interface layer was a single layer structure. When the thickness of the codeposition interface layer was 1 100 nm, the Mini composite had moderate interface bonding strength and the largest tensile strength of 626.0 MPa, and the corresponding fracture strain was 0.45%.