Structural Phase Transitions in Nonstoichiometric Compounds
This monograph gives an account of the state of the art in investigations of order-disorder structural phase transitions in non-stoichiometric compounds of the type of interstitial phases. Extensive experimental data on the structure and properties of ordered phases, short-range order and local displacement of atoms are reported. The relationship between short- and long-range order in ordered structures is considered. The principles of phenomenological and microscopic theories of phase transitions in crystals are stated. The results of determination of order-disorder phase transition channels are presented and distribution functions of interstitial atoms in non-stoichiometric compounds are calculated. The order parameter functional method proposed to describe order-disorder structural phase transitions is discussed in detail. The application of this method is illustrated by calculation of atomic ordering in non-stoichiometric carbides of transition metals. The problem of the atomic ordering effect on some properties of non-stoichiometric compounds is discussed.
