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It is shown that on the basis of the disordered &phase (space group Fm3m) two ordered equilib rium phases with cubic (b'-phase, space group Fd3m) and trigonal (6"-phase, space group R3m or P3121) unit cells can be formed in titanium carbide TiCo.62 and carbidenitrides TiC,N, (z + y M 0.63), whereas only a cubic &'-phase has been observed in TiCO.BaHy. With increasing temperature the low temperature trigonal 6"-phase transforms at about 1053 K to the cubic 6'-phase which experiences disordering. The formation of the cubic 6'-phase at temperatures lower than 1053 K is explained by the difference between the order of 6 -+ 6' and 8 + 6" phase transitions. YCTaHOBJIeHO C y l l p X B O B a H U e Ky6IIWCKOk (IIpOCTpaHCTBeHHaH rpynnaFd3m

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In the presented work, a boron carbide sample with a purity of 99.9%, particle size [Formula: see text]–[Formula: see text]m and a density of [Formula: see text] was used. Boron carbide samples were irradiated with linear electrons in the energy range of 2.5 MeV at the doses of [Formula: see text], [Formula: see text] and [Formula: see text] at room temperature. XRD results show that only in the crystal structure of [Formula: see text] compound, among boron carbide samples irradiated in the dose rate from [Formula: see text] to [Formula: see text] phase transition does not occur. The observed decrease in the lattice parameter values was explained as the strengthening of the bonds as a result of the recombination of defects in the crystal by influencing electron fluence. Dynamics of Raman spectra change and analytic analysis of intensive and duplex modes in various electron fluxes in ([Formula: see text]) CBC-structure were performed and the occurring disorder in Raman active has been identified.

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