Paper PII-12

Calculation of the Equilibrium Phase Diagram of Fe‑C Alloy System by the ESTPHAD Method

Kövér Zsuzsanna^1,2, Roósz András¹

¹University of Miskolc, Materials Science Institute, Department of Physical Metallurgy

H-3515 Miskolc, Egyetemváros, Hungary

²Hungarian Academy of Sciences Research Institute for Technical Physics and Material Science

H-1525 Budapest, P. O. Box: 49., Hungary

The Equilibrium Phase Diagrams (EPhD) used often in the Materials Science simulation could be determined by complicate, time-consuming measuring methods (DTA, electrical resistance measuring, structure analysis). The curves of the diagrams could be determined by thermodynamical calculation methods too (i.e. Calculated Phase Diagrams, CALPHAD), however these calculations are complicated, they need many initial data and these can be perform in case of known measured phase diagram.

The EPhDs can be used in the course of simulation if the curves of EPhDs are known as a function. An easy to use EPhD calculation method with required accuracy has a big importance at the practical calculation. In order to solve this problem a simple, iterationless calculation method was developed which uses the measured data of EPhDs (Estimated Phase Diagrams, ESTPHAD).

It is possible to determine the liquidus and solidus curves and the partition coefficient as a function of the concentration of liquid or solid phase with this calculation method. The developed method was used to estimate the liquidus and solidus curves of iron based binary EPhDs. In order to validate this method the measured and the calculated data were compared. In this lecture the ESTPHAD method will be shown in case of Fe‑C alloy system. In Fig. 1. the digitalized and calculated data are compared in case of a part of Fe-C alloy system.

Fig. 1.