Evolution of Shock-Induced Orientation-Dependent Metastable States in Crystalline Aluminum

The evolution of orientation-dependent metastable states during shock-induced solid-liquid phase transitions in crystalline Al is followed using moving window molecular dynamics simulations. The orientation-dependent transition pathways towards an orientation-independent final state Hugoniot include both "cold melting" followed by recrystallization in [110]- and [111]-oriented shock waves and crystal overheating followed by melting in [100] shock waves. The orientation-dependent dynamics take place within a zone that can extend up to hundreds of nanometers behind the shock front.