Metastable multiphase materials are currently obtained by controlled crystallization of amorphous samples. This paper deals with the use of metastable equilibrium phase diagrams and related thermodynamic quantities to the kinetic analysis of primary crystallization of an undercooled liquid solution as obtained by calorimetric means. The analysis is performed as a function of the processing conditions, assuming thermodynamic and kinetic competition between several crystalline phases for nucleation and growth. The hierarchy of crystalline phases formation on both heating an initial amorphous alloy or on cooling the liquid solution follows a sequence mostly consequent with the different temperature dependence of the several quantities driving crystal formation.