Comparative study of phase transformations in carbon at different schemes of shock compression

Abstract

A comparative study of phase transformations in carbon-base materials at shock compression has been carried out according to two different schemes: in cylindrical ampoules with a central rod at a direct contact of explosives with the ampoule and in ampoules without the central rod with throwable outer shells. It has been found that in the shock compression on the second scheme a higher absolute output of diamond is achieved, but as opposed to the first scheme, the shock compression products do not virtually contain lonsdaleite or dense amorphous phase. The analysis shows that in the second case the states with lower pressures but higher temperatures, which lead to a transformation of metastable phases into stable diamond, are realized.