Contribution of the school of V. N. Eremenko to the investigation of phase equilibrium diagrams and the thermodynamics of metallic systems

Abstract

Information is given regarding the metallic systems investigated by V. N. Eremenko and his school over the decades 1960-1990. His. approach to predicting the phase equilibrium diagrams and thermodynamic properties of unknown systems, based on the generalization of experimental data obtained in this period, is discussed. The prediction level (methods of successive comparison, interpolation or extrapolation, correlation, thermodynamic modeling) depends not only on the amount and reliability of data generalized, but also on the thermodynamic properties of the systems under consideration. The necessity of using a combined approach, in which experimental and calculated phase diagram and thermodynamic data are used together, is emphasized. Mathematical optimization and evaluation of such data made it possible to obtain information on the thermodynamics and phase diagrams of previously unknown systems, and to establish a methodological base for predicting the phase diagrams of multicomponent systems of any degree of complexity.V. N. Eremenko assigned primary significance to the investigation of phase equilibria, construction of phase equilibrium diagrams for condensed systems, and study of the thermodynamic properties of alloys and compounds as the most important components of contemporary materials science. His investigations in these fields were initiated in the late 1940's, early 1950's [1,2] in the Institute for Ferrous Metallurgy of the Academy of Sciences of the Ukr. SSR and in the Kiev State University. They have been extended and continue to the present time in the school established by V. N. Eremenko at the Institute for Materials Science Problems of the Ukrainian Academy of Sciences.Phase equilibrium diagrams (PED) contain in themselves, and present in a concise graphical form, the most important information on the fundamental properties of simple and complex substances. As geometrical reflections of the relative thermodynamic stability of phases, they are reflections of the chemical interactions of the components --of the nature and strength of chemical bonds in the phases which coexist in equilibrium. As geometrical representations of the dependence of alloy phase composition and structure (and, thus, of the types of phase transformations) on equilibrium conditions, they are basic information for those who develop new materials, and also for chemists and physicists investigating the properties of substances. Experimental studies of structure, phase stability and phase equilibria; theoretical investigations of the nature and strength of chemical bonds; thermodynamic calculation of phase equilibria; and, fmaUy, critical evaluation and compilation of data on alloy thermodynamics and phase diagrams constitute, in a sense, a unified field of knowledge on the structure of alloys in the state of thermodynamic equilibrium (Fig. 1).All of the enumerated subjects are successfully pursued in Ukraine. V. N. Eremenko made a large contribution to the establishment and development of this field of materials science in the...