Berlin 2015 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 3: Microstructure and Phase Transformations
MM 3.2: Talk
Monday, March 16, 2015, 10:30–10:45, H 0106
Influence of short-range forces on melting along grain boundaries — •Claas Hüter1, Fabian Twiste1, Efim A. Brener2, Jörg Neugebauer1, and Robert Spatschek1 — 1Computational Materials Design Department, Max-Planck Institut für Eisenforschung, Düsseldorf, Germany — 2Peter-Grünberg-Institut 2, Forschungszentrum Jülich, Jülich, Germany
In metallurgical processing, elevated temperatures and reduced local transition temperatures can lead to phenomena of grain boundary induced failure, as e.g. hot cracking. We introduce a model which couples diffusional melting and nanoscale structural forces in a combined nano-mesoscale sharp-interface description. We obtain analytic and numerical solutions for melting processes at grain boundaries influenced by structural disjoining forces, focusing on the experimentally relevant regime of small deviations from the melting temperature. Though spatially limited to the close vicinity of the tip of the propagating melt finger, the influence of the disjoining forces yields a strong modification of the penetration velocity. Close to equilibrium the atomistic effects near the triple junctions can be expressed through a contact angle renormalization in a mesoscale formulation. For higher driving forces, significantly higher melting velocity than predicted from a purely mesoscopic description are found.