Dresden 2014 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 18: Poster Session
MM 18.14: Poster
Montag, 31. März 2014, 18:00–20:00, P4
Continuum modelling of grain boundary wetting — •Venkata Sai Pavan Kumar Bhogireddy1, Fabian Twiste1, Chi-Dzu Nguyen1, Claas Hüter1, Robert Spatschek1, Jörg Neugebauer1, Alain Karma2, and Efim Brener3 — 1Max Planck Institut für Eisenforschung, D-40237, Düsseldorf, Germany — 2Physics Department, Northeastern University, Boston, 02115, USA — 3Peter Grünberg Institut, Forschungszentrum Jülich, D-52425, Jülich, Germany
Grain boundary (GB) premelting describes the appearance of thin nanometric melt layers along grain boundaries already below the bulk melting point, which can lead to dramatic material failure. Amplitude equations modelling shows that the premelting transition depends on the misorientation between the grains due to short range interactions between the adjacent crystals. In the absence of a misorientation a translational shift between the grains can still lead to periodic modulations of the interaction potential in the spirit of gamma surfaces, hence linking mesoscopic continuum models to atomistic descriptions. The tail of these interactions can be predicted analytically, and the results are compared to numerical results, which are also valid at shorter distances. Furthermore, we investigate the possibility of a conventional phase field model based on the multi-obstacle potential to capture the premelting transition.
Apart from these static situations we also study the penetration of a melt front along the GB in an overheated crystal, taking into account the aforementioned short ranged interactions. We find that the penetration velocity is strongly influenced by the nanoscopic interactions.