Equation of state and evidence of enhanced phase transformation for shock compression of distended compounds

Shear stress and deformation is inherent to shock-wave compression. Shear deformation is enhanced when the material subject to shock compression is in an initial distended state. Shock Hugoniot data for full-density and porous compounds of boron carbide, silicon dioxide, tantalum pentoxide, uranium dioxide and playa alluvium are investigated for purposes of equation-of-state representation of intense shock compression. Hugoniot data of distended materials reveal evidence of accelerated solid–solid phase transition as a consequence of shock compaction and accompanying enhanced shear deformation. A phenomenological thermo-elastic equation-of-state model is constructed that accounts for both deformation-induced phase transformation and the extreme shock compaction of distended solids, and applied to the compounds studied.

► Hugoniot response of porous SiO2, UO2, B4C, Ta2O5, and playa alluvium.
► Application of the Rice–Walsh equation of state.
► Phase transformation is dependent on porous shock compaction deformation.
► Phase transformation is incorporated into the Rice–Walsh equation of state.