Dynamics of first order phase transitions : By K. Binder; Fachrichtung 11.1—Theoretische Physik, Universität, 66 Saarbrücken, West Germany

Abstract

It is well known (1-3) that firstorder phase transi� tions are frequently associated with noticeable heat effects. For example, melting is characterized as an exothermal process, whereas liquid-solid transforma� tion can occur with heat evolution. In the simplest case, the rates of these transitions can be described as a function of temperature in a standard way using the classical Arrhenius relationship. The nonlinearity and sluggishness of thermal processes in the small vicinity of phase transitions can give rise to typical nonlinear and nonsteadystate effects, namely, the multiplicity of steady states and oscillations. Here, we propose the simplest dynamic model of a phase transition and perform its parametric analysis. Conditions have been recognized for the existence of three and five steady states; the ranges of the parame� ters where autooscillations exist in a dynamic system have been found; and characteristic parametric and phase portraits of the mathematical model have been designed. The process dynamics in the vicinity of a phasetransition point has been shown to be rather complex. The processes observed here include the hys� teresis of temperature dependences, undamped con� centration and temperature oscillations, and consid� erable dynamic bursts during the establishment of a steady state.