Mechanisms of martensitic transformations in boron nitride and conditions of their development

The dependence of the pressure threshold of martensitic transformations on the disordering degree of starting structures is considered for graphite-like BN into diamondlike BN modifications transitions. The effect of loading conditions on transformation mechanisms of rhombohedral BN into zinc blende or wurtzite modifications is analyzed also. Analytical relations obtained allow to explain the experimental data and to predict a behavior of various graphite-like structures under different p, T conditions.