Channel segregation during columnar solidification: Relation between mushy zone instability and mush permeability

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 segregations a benchmark test case solidification Sn-Pb alloy. An Opensource CFD software OpenFOAM used to simulate alloy side-cooled rectangular cavity. very well characterizes shown numerical simulations. near-liquidus part region more prone initiation instability, can initiate formation Permeability its derivative respect liquid fraction outer (liquid than 0.9) plays key role this be responsible development segregates. are also compared those remelting criterion, it has been noticed severely under these defects (e.g., their number length). We local might not necessary channel; some destabilization due could sufficient.