DISSOCIATIVE PHASE-TRANSITIONS FROM HYPERVELOCITY IMPACTS

Molecular dynamics simulations are used to study hypervelocity impacts of an ultrathin flyer plate with a semi-infinite two-dimensional model diatomic molecular solid. These hypervelocity impacts are shown to produce a dissociative phase transition from a molecular to a close-packed solid in the target material. Although this close-packed phase persists for less than 10 picoseconds and is confined to a domain less than 10 nanometers wide it nevertheless behaves in a manner consistent with continuum theory.