Seminars and Events

More physics into Calphad modeling, finite temperature calculations, an example with the Fe-W system

Date/Time: 30.09.2015. 11:00 a.m.

Aurélie Jacobs, Forschungszentrum Jülich, Jülich

Over the last four decades, thermodynamic modeling have shown its importance for its use in the understanding of phase stability in multicomponent systems. Thermodynamic databases have been built and are now available for several alloys. Building such thermodynamic databases require a large amount of experimental data on the considered systems.

In high temperature systems, there are often lacks of experimental data due to the difficulty hampered by the high temperature (contamination of the samples, high vapor pressure, and cost). The thermodynamic modeling of such system can so be only given approximately and can lead to serious problems by using in higher multicomponent systems.

A reliable thermodynamic modeling of a phase diagram require to have good experimental data set in order to determine the Gibbs energy functions of the different phases in the system. In absence of such valuable data, phonon calculations can be used to provide the temperature dependence of the Gibbs energy functions.

In the present work, it is proposed to give a thermodynamic optimization of the Fe-W by limiting to a minimum the amount of fitted parameters to the experimental data. It is proposed to use phonon calculations of the intermetallic phases without adding excess parameters for these phases.

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