C/C-ZrC-SiC matrix composites are widely used in aerospace field as a kind of promising thermal protection materials. But C/C-ZrC-SiC matrix composites prepared by reactive melt infiltration (RMI) have the disadvantage of low mechanical properties, which is the main factor restricting its development and application. In order to improve the fiber damage and mechanical properties of the C/C- SiC-ZrC matrix composites, 300 nm pyrolysis carbon(PyC) interface, 300 nm PyC/SiC double-layer interface, and 100 nm, 300 nm, and 800 nm (PyC+SiC) co-deposited interfaces were introduced into carbon fiber needled preform by chemical vapor deposition(CVD); and then the C/C-SiC-ZrC matrix composites were prepared by RMI. The phase composition, micro-morphology, element distribution and interface damage were investigated by XRD, SEM, EPMA and TEM, and the mechanical properties of the composites after RMI were evaluated by three-point bending tests. The results show that the introduction of the interfaces not only protect the fibers, but also improve the bonding state between the fibers and the matrix, which greatly avoids the erosion of the carbon fibers by RMI. The PyC interface provided limited protection to the fibers, while the PyC/SiC double-layer interface provided the best protection. The interface type and interface thickness have an important effect on the mechanical properties of the composites. When the interface thickness is the same, the flexural strength of the composites with (PyC+SiC) co-deposited interface and the composites with PyC/SiC double-layer interface are 162.80 MPa and 208.58 MPa, respectively, which are superior to those of the composites containing the PyC interface; the mechanical properties of the composites show a first increase in the thickness of the interface with the increase in the thickness of the interface with the increase in the thickness of the interface. With the increase of (PyC+SiC) co-deposited interface thickness, the mechanical properties of the composites show the trend of increasing and then decreasing.
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