Construction on nonequilibrium constitution diagrams of the T-n type and their use for analysis of the temperature dependence of phase composition
An examination of the dependence of the free energy of liquid and solid phases on volume in a one-component substance is used as a basis to prove that it is possible to use a conoid law to construct phase diagrams of a new type: temperature-density of the substance (T-n). A similar approach can be applied in a more complicated case: to multicomponent systems and to phases of an arbitrary nature. An analysis is made of nonequilibrium T-n diagrams for Mg constructed in the temperature range from 200 to 1200‡K by the method indicated. The conditions necessary for Mg to change from equilibrium states to the region in which the liquid and solid phases coexist are determined.