Experimental determination of mushy zone permeability in aluminum-copper alloys with equiaxed microstructures

An experimental apparatus for measuring the mushy zone permeability of aluminum-copper alloys with equiaxed microstructures has been constructed. Permeabilities have been measured for high solid fractions (0.68 to 0.91) and different dendrite morphologies. Microstructure characterizations on both the interdendritic and extradendritic length scales have been performed on the samples. The results are in fairly good agreement with the predictions of the Kozeny-Carman relation and with more recent theory that takes flow partitioning between interdendritic and extradendritic regions into account.