Chemical Physics and Dynamics of Surfaces – Dynamics of interfaces – 2D lamellar and fibrous eutectic fronts in massive samples

Directional solidification in “thick” samples (typically 0.5 mm thick) of CBr4-C2Cl6 and succinonitrile-camphor alloys of concentrations inside the eutectic plateau.

The solid is two-phased, composed of two different crystalline phases α and β. Diffusive dynamics are at the origin of the periodic alternation of the lamellae or fibers of the two phases. The growth rate (less than 1 µm / s), aligned with the thermal gradient axis, is directed off the screen (movies are accelerated). The growth front is seen “from the top”.

Caption: Stationary lamellar eutectic structure of the CBr4-C2Cl6 alloy (V = 0.37 µm/s). The thickness of the sample (350 µm) takes the whole height of the image.

Caption: Zigzag structure. Lamellar eutectic of CBr4-C2Cl6 alloy. Height : 300 µm.
(S. Akamatsu, S. Bottin-Rousseau, G. Faivre, Phys. Rev. Letters, 93, 175701 (2004)).

Caption: Eutectic fibrous structure. Succinonitrile-camphor eutectic alloy. V = 0.007 µm/s. Width: about 1 mm. TRANSPARENT ALLOYS project (ESA/NASA). Collaboration: U. Hecht and V. Wytusievich, ACCESS, Aachen, Germany).