Topology of the liquidus hypersurface of the phase diagrams of quaternary systems

Abstract

Consideration was made of structural features of the liquidus and solidus hypersurfaces of the isobaric melting diagrams of quaternary systems with a single liquid phase and solid phases of constant compositions which undergo neither phase transitions nor decomposition into other phases while cooling. An intimate relationship between the topologies of such hypersurfaces was noted. The oriented graph of the liquidus hypersurface can be obtained from the graph of the solidus hypersurface by drawing arrows on its edges in the direction of decreasing temperature along the corresponding monovariant lines or by labeling its vertices with symbols of types of invariant reactions. An example was given for constructing different variants of the melting diagram of a system that correspond to the same topology of the solidus hypersurface.