Study of near-critical point thermodynamics of molybdenum by isentropic expansion and isobaric heating

In this work release isentropes of shocked porous molybdenum were investigated. Samples with initial porosity m=ρ0/ρ=1.4; 3.1 were used to achieve near-critical entropy states of metal after shock compression. Shocked samples were expanding into helium with different initial pressures. The brightness temperature (TP) of metal and the velocity of shock wave in helium were measured by fast optical pyrometer. Shock wave velocity value allowed to determine the final pressure (PS) of expansion of metal and the velocity of metal expansion (WS). Location of peculiarities on isentropes in PS-WS and PS-TP diagrams gives the location of their entrance into two-phase region. Estimation of molybdenum critical temperature and pressure were done on the basis of experimental data