Phase Transitions of C70 Fullerite with Hexagonal Closed‐packed Structure under Shock‐wave Loading

Abstract

Shock‐induced phase transitions of C70 fullerite with hexagonal close‐packed structure were experimentally studied in the pressure range 8 to 36 GPa. It was found that C70 fullerite undergoes a series of polymorphic phase transitions under step‐like shock‐wave compression. The hexagonal close‐packed structure of C70 fullerite remained practically unchanged at shock pressure up to 8 GPa. Shock‐induced transformation of the hexagonal structure into face centered cubic structure was fixed at pressures in the range 8–23.5 GPa. The depth of this transformation increases with the shock pressure. Upon further increase of the shock pressure the destruction of C70 molecules occurs. This destruction is accompanied by the formation of graphite‐like carbon.