Phonon contribution to the thermodynamics of pure and mixed clusters in bcc-Fe


Phonon contribution to the thermodynamics of pure and mixed clusters in bcc-Fe

Talati, M.; Posselt, M.; Bonny, G.; Al-Motasem, A. T.; Bergner, F.

The irradiation-enhanced nanostructural evolution in reactor pressure vessel steels is a multiscale phenomenon. It can be effectively studied by rate theory for which necessary parameters must be obtained through atomistic simulations. The present work focuses on the phonon contribution to the thermodynamics of nanoclusters consisting of vacancy and/or Cu. In all calculations the most recent Fe-Cu interatomic potential developed by Pasianot and Malerba is employed. The vibrational density of states determined by the dynamical matrix method is used to calculate the phonon contribution to free energy of formation and free binding energy of the clusters. Pure bcc-Fe and pure fcc-Cu are used as references in the calculation of the free energy of formation. The vibrational contribution to the total free energy of these metals determined in this work is compared with available CALPHAD data and with literature data obtained by first-principle methods or interatomic potentials. In the case of pure vacancy clusters and for many mixed vacancy-Cu clusters the absolute value of the total free binding energy decreases with increasing temperature. Pure Cu clusters show the opposite behavior.

Keywords: Vibrational Density of States; Total free energy; Free binding energy; bcc-Fe; Thermodynamics; Molecular Dynamics Simulation

  • Poster
    DPG Frühjahrstagung der Sektion AMOP (SAMOP) und der Sektion Kondensierte Materie (SKM) 2011, 13.-18.03.2011, Dresden, Germany

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Publ.-Id: 15435