Thermophysical and mechanical properties of a three-dimensional Hi-Nicalon/SiC composite

Key thermophysical and mechanical properties of a three-dimensional Hi-Nicalon™/silicon carbide (SiC) composite were tested. The relationship between the thermal expansion coefficient and temperature of the composite from room temperature (RT) to 1400°C was similar to that of chemical vapor deposition SiC. The thermal diffusivity of the composite could be well fitted by a logarithmic function. The composite exhibited excellent mechanical properties at RT and high temperature in vacuum. At RT, the flexural strength and flexural modulus were 1193 MPa and 255.6 GPa, respectively. Above 1200°C, the value of the flexural strength and flexural modulus at high temperature in vacuum decreased as the temperature increased, while the fracture toughness increased as the temperature increased.