Disorder-order phase transformations and electrical resistivity of nonstoichiometric titanium carbide

Phase transformations of the disorder-order type in the homogeneity region of nonstoichiometric titanium carbide TiCy (0.5<y<1.0) have been studied. It has been established that, depending on the actual composition of TiCy, there may form in it for T<980–1000 K a cubic or a trigonal ordered Ti2C phase (space groups Fd3m and R 3m , respectively) and a rhombic ordered Ti3C2 phase (space group C2221). The effect of ordering on the electrical resistivity of the nonstoichiometric carbide TiCy was studied, and the temperatures of the reversible disorder-order equilibrium transitions determined. The ordering in titanium carbide is shown to be a first-order phase transition.