Buoyancy-thermocapillary instability: the role of interfacial deformation in one- and two-component fluid layers heated from below or above

The March 1987 Les Houches workshop on “Propagation in Systems far from Equilibrium” allowed us to compare the state of research in a number of different fields where instabilities occur. It appeared clearly that the field of solidification has been much less systematically explored than those, for example, of Rayleigh-Benard instabilities or convection in mixtures. Many questions have yet to receive an answer. The aim of the present text is to examine some of them in the light of the results of this Workshop. However, we shall begin by a brief review of the literature on the subject.

Cellular instabilities in directional solidification

Directional solidification of metallic alloys: The nature of the bifurcation from planar to cellular interface

Theory of cellular solidification of binary alloys with applications to succinonitrile-salol

A theory is presented for predicting the size of ice crystals which result from steady-state, unidirectional growth within aqueous agar gels. Cellular arrays of adjacent ice crystals were separated by an amorphous water-agar membrane at a composition near the vitrification point. Using this vitrification composition and both a steady-state condition and a minimum free energy criterion, the size of ice crystals was predicted for a given solidification velocity and diffusion condition. It was found, however, that this simple model could not predict the trend towards larger crystal sizes that was observed when the initial agar concentration in the gels increased from 3% to 10% by weight agar.

A.L. Coulet

Papers

Cell size of dilute binary alloys

Taille cellulaire de monocristaux de cuivre contenant du silicium

Interfacial stability during the growth of a dilute binary alloy - thermodynamical approach

Observation par attaque chimique et topographie x des structures cellulaires de monocristaux d'alliages métalliques binaires dilués