On Static and Dynamical Young's Condition at a TrijunctionC. Caroli1 and C. Misbah2
1 Groupe de Physique des Solides Unité associée au CNRS, Universités Paris 7 et 6, 2 Place Jussieu, 75005 Paris, France
2 Laboratoire de Spectrométrie Physique Unité associée au CNRS, Université Joseph Fourier, Grenoble I, BP 87, Saint-Martin d'Hères, 38402 Cedex, France
(Received 18 November 1996, revised 20 February 1997, accepted 10 June 1997)
Using a consistent purely kinetic model we show that Young's condition at a trijunction results from a chemical and not a mechanical equilibrium, as is often believed in the literature. In an out-of equilibrium situation this condition is altered in a way such that the triple point acquires an effective mobility. The order of magnitude of the mobility is fixed by a velocity scale associated with chemical attachment at the interface, and not by the sound speed. While for ordinary eutectics is large (except in rapid solidification experiments) in comparison to the growth speed, implying a quasi-instantaneous mobility, finite mobility effects should show up for faceted eutectics as well as for eutectoid transformations.
© Les Editions de Physique 1997