THE USE OF METASTABLE PHASE-DIAGRAMS IN PRIMARY CRYSTALLIZATION KINETICS STUDY

Metastable multiphase materials are currently obtained by controlled c rystallization of amorphous samples. This paper deals with the use of metastable equilibrium phase diagrams and related thermodynamic quanti ties to the kinetic analysis of primary crystallization of an undercoo led liquid solution as obtained by calorimetric means. The analysis is performed as a function of the processing conditions, assuming thermo dynamic 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 so lution follows a sequence mostly consequent with the different tempera ture dependence of the several quantities driving crystal formation. ( C) 1998 Elsevier Science B.V.