Yu.I. Ustinovshchikov Physical-Technical Institute of the Ural Branch of the Russian Academy of Sciences, Kirova str. 132, Izhevsk, 426001, Russian Federation
This paper presents a critical analysis of research on thermodynamics, kinetics and morphology of diffusion phase transitions in alloys. It is shown that the key thermodynamic stimulus for diffusion phase transitions is the chemical potential difference due to a change in the sign of the chemical interaction between the component atoms. It is explained how the sign of the chemical interaction energy can be obtained from experimental measurements. Examples are given to illustrate the kinetics and morphology of the ordering-separation phase transition in Ni- and Co-based alloys. It is shown how introducing the concept of the ordering-separation phase transition affects our thinking in this area.