Effect of Hydrothermal Carbon Interphase Thickness on Mechanical Properties of Cf/SiBCN Mini-Composites

The carbon fiber/siliconboron carbonitride (C-f/SiBCN) mini-composites exhibit poor mechanical properties due to the strong fiber-matrix bonding, which can be improved by introducing the hydrothermal carbon (HTC) interphase and further engineered by optimizing the HTC interphase thickness. To investigate the effect of the HTC interphase thickness on the mechanical properties of the C-f/SiBCN mini-composites, the tensile properties of the C-f/SiBCN mini-composites with different HTC interphase thicknesses were compared. The tensile test results show that the fracture behavior of the C-f/SiBCN mini-composites changes from brittle fracture to non-brittle fracture after introducing the HTC interphase. In addition, the tensile strength and work of fracture (WOF) of C-f/SiBCN mini-composites first increase and then decrease with the HTC interphase thickness increasing. The corresponding C-f/SiBCN mini-composites with 120 nm HTC interphase exhibits the maximum tensile strength and WOF, which are improved by around 4 times and 18 times, compared with the mini-composites without interphase. This work shows that the introduction of HTC interphase is conducive to improve the tensile properties of the C-f/SiBCN mini-composites, which can provide a preliminary basis for further investigating the effect of HTC interphase on the mechanical properties of the C-f/SiBCN composites.