Shock Compression, Adiabatic Expansion and Multi-Phase Equation of State of Carbon

The compressibility of graphite and diamond samples of various initial densities has been studied experimentally in shock waves at pressures in the range 5–74.5 GPa. The states of graphite samples have been investigated also under reflected shock loading up to 182 GPa and in adiabatic release waves at pressures down to 4.5 GPa. A semiempirical equation‐of‐state model, which takes into account the effects of polymorphs transformation and melting, is proposed. An equation of state is developed for the graphite, diamond, and liquid phases of carbon, and the critical analysis of calculated results in comparison with the newly acquired and available high‐energy‐density experimental data is made.