Melting diagrams of quaternary systems with a single compound

Abstract

Topological analysis was made of the structure of the melting diagrams of quaternary systems with a single compound. Graphs of phase diagrams were constructed, which show the relative positions of invariant points and monovariant lines on the liquidus hypersurface. It was shown that there exist two types of diagrams with a binary compound and six types of diagrams with a ternary compound. Quaternary compound C can form by congruent crystallization reaction L = C (I) or by the interaction of melt with components: L + K₁ = C (II), L + K₁ + K₂ = C (III), or L + K₁ + K₂ + K₃ = C (IV). There are 23 types of diagrams with reaction (I) and 23 types of diagrams with reaction (II), which described by identical graphs; 25 types of diagrams with reaction (III); and 6 types of diagrams with reaction (IV). Fragments of the obtained diagrams correspond to various topological situations, which may occur in more-component systems.