Modelling the mushy region in a binary alloy

In developing models of solidification systems a central element is the treatment of the mushy region. The aim of this paper is to investigate a number of alternative approaches to account for the nature of the mushy region in a model of a solidification system. Starting from two limiting assumptions for the nature of the mushy region, a number of alternative physical situations are identified from which one-phase models can result. These models are compared in the context of a simple test problem.