True phase diagrams

Abstract

With the use of today's computer softwares, phase diagrams can readily be plotted with a wide choice of variables on the axes. Hillert defined a true phase diagram as a diagram where each point uniquely defines the stable phases. He also showed that not all choices of axis variables give true phase diagrams. In this note we will demonstrate that although the rules stated by Hillert are necessary they are not sufficient to have true phase diagrams. © 2014 The Author(s).