SHOCK COMPRESSION AND ISENTROPIC EXPANSION OF NATURAL URANIUM

The dynamic compression of natural uranium of normal and lower initial density in the ranges of porosity of 1-4.8 and pressure of 20-200 GPa is experimentally investigated. The method of barriers is used to reg ister the run of four release isentropes for shock-compressed porous s amples in a wide range of thermodynamic parameters-from the states on shock adiabats under pressures from 70 to 350 GPa to near-critical sta tes under pressures of several tens of MPa. The experimental data are compared with the results of calculations performed by the wide-range equation of state for uranium, including for the effects of high-tempe rature melting and evaporation.