Sound Velocities in Porous Iron Shocked to 177GPa and theImplications for Shock Melting

Sound velocities in shock-loaded solids are not only important to determine bulk moduli of solids at high pressures, but also crucial to inform the shock melting of solids upon loading. In this letter, we first report on shock melting of porous solids at high pressures by measuring sound velocities in the porous iron of average density 6.90g/cm³ in the pressure range of 110-180GPa. The measured sound velocity softens at pressures from 122 to 156Gpa, which may be attributed to shock melting of the porous iron.