• Brown, D. J.
• Banaszek, Jerzy

Abstract

A front-tracking technique on a fixed Cartesian grid, based on the kinetics of dendritic growth, is used to model the progress of anundercooled columnar dendritic front in non-equilibrium 2D solidification controlled by conduction and thermal natural convection. The effectof the alloy latent heat of fusion is included in this single-domain model through a careful definition of source terms in the energy conservationequation to account for both the advance of solidification front and subsequent thickening of the mushy zone within a control volume. The modelis compared with the enthalpy approach showing its superiority in the detection of the undercooled liquid zone and, thus, in potentiallymodelling of columnar/equiaxed grain structures. It is used to predict the influence of both alloy composition and convective heat transfercoefficient on the size of the undercooled liquid zone in front of columnar dendrite tips during solidification of Al–Cu in a square mould. Thepredictions obtained confirm that natural convection in the melt reduces local temperature gradients and thus widens the undercooled liquid zoneahead of a curve joining columnar dendrite tips, increasing the potential for growth of equiaxed grains

Topics

• impedance spectroscopy
• grain
• melt
• solidification
• joining
• alloy composition
• heat of fusion