Shock-Induced Phase Transitions in Oriented Pyrolytic Graphite

Shock-Induced Phase Transitions in Oriented Pyrolytic Graphite 

Carbon materials have particular characteristics due to differences in chemical bond formation. Allotropic forms of carbon that have been discovered can be categorized into five types from the standpoint of the type of hybridization of the valence orbitals (1) -hybridization (2) -hybridization (3) -hybridization (4) mixed hybridization (sp3 + sp2) and (5) a valance state characterized by a fractional degree of hybridization (spm, where 1 m 3, and m 2) [1]. Diamond, caibynes, diamond-like carbon, and fullerenes correspond to groups (1), (3), (4), and (5), respectively. 

In the work reported in this chapter, oriented pyrolytic graphite was shock-loaded at pressures up to 15 GPa perpendicular or parallel to the basal plane of the graphite. The phase transitions of graphite to other carbon allotropes will be discussed using nanostructural data obtained by high-resolution electron microscopy (HREM). 

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