Synergistic densification and performance of Cf/ZrB2–SiC–ZrC composites via a hybrid HP-PIP strategy

A hybrid process combining slurry infiltration, low-temperature hot-pressing (HP), and precursor infiltration and pyrolysis (PIP) was developed to fabricate continuous C f /ZrB 2 -SiC-ZrC composites. Optimized HP at 1200 °C (40 MPa, 15 min) established a robust porous skeleton, which significantly reduced the subsequent PIP cycles to six, achieving a high bulk density of 2.93 g/cm 3 and low open porosity of 8.45 %. The optimal composite exhibited a flexural strength of 109.47 MPa. Notably, while the fracture toughness was moderate (3.77 MPa·m 1/2 ), the material demonstrated exceptional damage tolerance with a high work of fracture (578.98 J/m 2 ), attributed to extensive fiber pull-out and crack deflection mechanisms. After oxidation at 1500 °C, a continuous ZrO 2 -SiO 2 scale formed, allowing the composite to retain 30 % of its strength and maintain structural integrity. This work offers a strategic pathway for balancing densification efficiency and damage tolerance in UHTCMCs.