As a molten alloy or any multi-component liquid is cooled and solidified the growing solid phase usually forms a porous matrix through which the residual liquid can flow. The reactive two-phase medium comprising the solid matrix and residual liquid is called a mushy layer. Buoyancy forces, owing primarily to compositional depletion as one or more of the components of the alloy are extracted to ...

We report on a series of experiments in which a Hele-Shaw cell containing aqueous solutions of NH4Cl was translated at prescribed rates through a steady temperature gradient. The salt formed the primary solid phase of a mushy layer as the solution solidified, with the salt-depleted residual fluid driving buoyancy-driven convection and the development of chimneys in the mushy layer. Depending on...

A model of mushy zone instability is developed for characterization and prediction channel segregation in castings. The highlights the connection with mush permeability. new criterion amplification derived, which depends on interdendritic velocity, isotherm temperature gradient, explicitly capability segregates illustrated by comparing estimated possible locations that numerically simulated seg...

We investigate the effect of an external shear flow on the buoyant instabilities inherent in the directional solidification of a dendritic mushy layer. In the presence of an external shear flow, perturbations of the mush–liquid interface lead to perturbed flow in the bulk fluid that create pressure variations along the mush–liquid interface. These pressure variations drive flow in the mushy lay...

— A proof of existence is given for a stationary model of alloy solidification. The System is composed ofheat équation, soluté équation and Navier-Stokes équations. In the latter, Carman-Kozeny penalization of porous medium models the mushy zone. The problem is first regularized and a séquence of regularized solutions is built thanks to Leray-Schauder's fixed point Theorem. A solution is then e...