The structure of silicon, along with mixtures of silicon and boron carbide (B4C) powders and silicon and diamond powders with different proportions after mechanoactivation, has been studied by transmission electron microscopy (TEM) methods. It was shown that silicon and boron carbide experience twinning according to the known twinning mechanisms. In addition to the initial phase with a diamond lattice, the particles of two other phases were detected for silicon, including: the Kasper phase (SiIII) and lonsdaleite (SiIV). We established that the phase transformations in silicon can happen due to different mechanisms.
