Rheological behavior of the mushy zone at small strains

The modeling of the hot-tearing phenomena at the end of solidification requires the development of specific constitutive equations for the mushy zone. The presence of liquid films in the solid-liquid mixture has important consequences on the rheological behavior of the mushy zone. This aspect is particularly treated in order to propose a constitutive equation for the mushy zone in the low strain region. Starting from the behavior of the fully solid material, the mush is modeled as a porous medium saturated with liquid with partial cohesion. The cohesion of the mush is treated as an internal variable for which an evolution equation is proposed. Experimental data on a Sn-Pb model alloy both in the fully solid state and in the mushy state are used in order to study the advantages and the limitations of the proposed constitutive equation, (C) 2002 Elsevier Science B.V. All rights reserved.