Experimental difficulties associated with permeability measurements in aluminum alloys

The general principles and experimental difficulties associated with the me asurement of permeability in aluminum alloys have been discussed, in order to ease the further development of experimental methods suitable for such m easurements. In order to avoid the surface-tension effects associated with liquid/gas interfaces in the narrow channels of the mushy zone, a flux melt can be used at the inlet of the permeameter. Electron-beam (EB) welding ha s been shown to be a suitable method for ensuring a complete wetting betwee n the sample and flux after remelting to the test temperature. Moreover, th e influence of the permeameter design and the experimental procedure on gra in detachment, preferred-flow channel formation, and coarsening have been r evealed through microstructural images.