Simulation of shock-induced fragmentation and vaporization in metals

Simulations of experiments on shock-induced melting, fragmentation and vaporization in aluminum and zinc targets are presented. A titanium impactor moves at a velocity of 10.4 km/s and causes melting of these materials in a shock wave. Under rarefaction the thermodynamic path crosses the liquid–vapor coexistence boundary and enters into a metastable liquid region. Liquid in a metastable state may undergo either liquid–vapor phase separation or mechanical fragmentation. Homogeneous nucleation theory and the mechanical fragmentation criterion of Grady are taken into account to control the kinetics of these processes in our model. The first effect dominates in the vicinity of the critical point, the second one – at lower temperatures. Analysis of phase transitions and kinetics of phase separations is performed using a thermodynamically complete equation of state with stable and metastable states for all materials under consideration.