The effect of coarsening upon macrosegregation close to a cast surface
- SINTEF Materials Technology, Oslo (Norway)
A one dimensional mathematical model for macrosegregation caused by exudation and solidification shrinkage is presented. The model is used to study the effect of coarsening upon interdendritic flow and the associated macrosegregation close to a cast surface and exudation at the surface. An essential parameter in macrosegregation modeling is the permeability. The permeability depends on the instantaneous, local microstructure of the mush zone, and the present model incorporates the effect of coarsening due to ripening. The coarsening appears to have a significant effect upon the exudation rate and the solute depletion close to the surface. It is possible to select a constant mean value for the secondary dendrite spacing, by which one obtains fairly reasonable agreement with the final macrosegregation predicted when coarsening is accounted for. However, such a mean value is not known a priori, and it results in a depleted zone width being too small.
- OSTI ID:
- 227782
- Report Number(s):
- CONF-9509118--; ISBN 0-87339-297-3
- Country of Publication:
- United States
- Language:
- English
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