Complex ordering in solid solutions with ω(0)-phase structure

In the framework of statistical theory atom ordering on lattice points and octahedral interstitial sites of solid solutions with the ω( )-phase structure is considered. A possibility of formation of superstructures of the A2B4O, A2B4O2, A2B4O3 type under oxygen atom ordering passing with ''a zero'' (k=0) stare By the thermal analysis method the phase diagram (''zero matrix'' - oxygen section) in the Ti-Zr-O and Ti-Hf-O systems is investigated. Thermodynamics of ordering and its relation to experimentally observed peculiarities of these systems is discussed