Abstract
Extensive interlamellar spacing measurements on directionally solidified Al–CuAl2 eutectic alloys show that in this system the eutectic exhibits a limited range of spacings rather than a unique spacing during steady state growth at a constant velocity. The minimum spacing observed corresponds to the extremum spacing predicted by the Jackson–Hunt model. However, the maximum observed spacing is much less than the maximum spacing predicted by the theory. In this paper the assumption of a planar interface made by Jackson and Hunt is relaxed and the boundary element method is used to calculate the solute distribution for a curved interface. An iterative technique is used to calculate the maximum spacing for which a selfconsistent interface shape can be calculated for a range of velocities. This maximum selfconsistent spacing shows much closer agreement with the maximum observed spacing than that calculated on the assumption of a planar interface. The deepest point on the selfconsistent interface shape at the maximum spacing does not lie in a deep pocket. It is below the conjunction level but close to it.
MST/1932
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