The ablation and mechanical behaviors of C/(SiC-ZrC)_n multi-layer structure matrix composites by chemical vapor infiltration

Continuous carbon fiber reinforced (SiC-ZrC)_n multi-layer structural matrix composites were prepared by isothermal chemical vapor infiltration method. The microstructure, bending and ablation behavior of the composites with different number (n, n = 1, 2, 4) of SiC-ZrC layer were studied. The fracture morphology was step-like fracture. With the increase of n, the number of interfaces doubled, benefiting that the cracks kept deflecting and branching at the interface to consume lots of energy. The bending strength increased from 127.63 MPa (n = 1) to 276.85 MPa (n = 4). After ablation, among the prepared composites, C/(SiC-ZrC)₄ composite not only had the highest residual bending strength (169 MPa), but also had the best ablation resistance, which the mass and linear ablation rates were 1.17 ± 0.19 mg/s and 7.50 ± 0.56 µm/s, respectively.