Equations of State That Describe the Phase Transition of Order–Disorder Type Substitution in Binary Alloys

Abstract

Equations of state are considered that correspond to a model of static concentration waves which describe order-disorder phase transitions of the substitution type in binary alloys. A phase diagram associated with a three-dimensional order parameter that describes ordering in Cu-Au alloys is presented as an example. It is established that the equations of state of the theory of concentration waves allow additional solutions not considered in existing theories of ordering based on the hypothesized predominant role of pair interactions. These solutions correspond to states that are partially ordered and stable over a wide area of the phase diagram.