Multiphase equations of state for metals under pulsed power influences

Adequacy of description of the thermodynamic properties and phase changes of materials is important for simulations of processes in condensed media under pulsed power influences, specifically such as an electrical explosion of conductors¹. In this work, a semiempirical equations-of-state model with taking into account polymorphic phase transformations, melting and evaporation as well as metastable state realization is proposed. Multiphase equations of state for metals (such as tungsten, molybdenum, titanium) are presented. As distinct from the previously obtained equations of state for the metals², a new form of expressions of the individual terms of the thermodynamic potential Helmholtz free energy is developed. It takes greater account of the thermal contribution of atoms in the liquid phase as well as the melting and ionization effects. A critical analysis of calculated results is made in comparison with available data from experiments with shock wave loading, isentropic release and high current pulsed heating.