Effects of Cf/C density on microstructure and properties of 3-D Cf/ZrC composites prepared by liquid metal infiltration

• This paper presents a novel preparation method for 3-D Cf/ZrC composites.
• The 3-D Cf/ZrC composites were fabricated at temperature as low as 1200 °C.
• Effects of Cf/C density on structure and properties of the composites were studied.
• The composites show excellent mechanical and anti-ablative performance.

Three-dimensional braided carbon fiber-reinforced ZrC matrix composites, 3-D Cf/ZrC, were fabricated by Liquid metal infiltration process at 1200 °C. Porous carbon/carbon (Cf/C) composites with various densities were used as preforms, and the effects of Cf/C density on microstructure and properties of the 3-D Cf/ZrC composites were investigated. The results show that the composites are composed of carbon, ZrC and residual metal. Both microstructure and properties of the 3-D Cf/ZrC composites are apparently affected by Cf/C density. With increasing density of Cf/C preform, the density of 3-D Cf/ZrC composites decreases while the open porosity increases. The composites obtained from the Cf/C preform with a density of 1.12 g/cm3 have the best mechanical properties, with flexural strength of 286.2 ± 11.4 MPa, elastic modulus of 83.5 ± 6.8 GPa and fracture toughness of 9.2 ± 0.6 MPa m1/2. The composites exhibit excellent ablation resistance, and the mass rate and the linear ablation rate under an oxyacetylene torch are as low as 5.1 ± 0.4 mg s−1 and 1.1 ± 0.3 μm s−1, respectively.