Internal friction and Young’s modulus of a carbon matrix for biomorphic silicon carbide ceramics

The amplitude, temperature, and time dependences of the Young’s modulus and internal friction (ultrasonic attenuation) of a eucalyptus-based carbon biomatrix intended for preparing biomorphic silicon carbide ceramics were studied. Adsorption and desorption of molecules of the ambient medium (air) was shown to determine, to a considerable extent, the effective Young’s modulus and acoustic vibration decrement of a specimen. A doublet maximum in the temperature dependence of ultrasonic attenuation was observed at a temperature close to the sublimation temperature of solid CO₂. The microplastic properties of the material were estimated from acoustic measurement data.