Iron—Carbon Fe—C

Abstract

Because of the technical importance of the phase relationships in the iron-carbon system, the number of its investigations is astronomical. Even so, few changes to the phase diagrams of the stable (Fe-graphite) and the metastable (Fe-cementite) systems had to be made in the past (Hansen [A], Elliott and Gleiser [1]). However, a novel feature of the phase boundary evaluation has been introduced by the application of thermochemical calculations, leading to the evaluation of true equilibrium diagrams. In this way, Chipman [2] dealt with the ranges up to 12 wt.%, that is 39 at.% C at 0–3,000°C. Schürmann and Schmid [3] went further by calculating the equilibria of graphite and cementite with ferrite and austenite separately. Because of the small differences in Gibbs energy, the metastable equilibria are of particular significance.