Macrosegregation in binary AlSi7 alloys resulting from the application of time dependent magnetic fields
The resulting macrosegregation due to the application of time dependent magnetic fields during solidification of AlSi7 alloys is analyzed using the software package CrysVUn. Directional solidification from the bottom to the top at a constant growth velocity vG=0.1mm/s and temperature gradient G1=4K/mm in a small scale sample with the radius R=4mm is simulated. Severe segregation is found in the case of traveling magnetic fields. Nevertheless, also rotating magnetic fields are creating a highly segregated zone at the axis of the sample beyond a certain magnetic field strength. The sensitivity of the numerical predictions regarding the applied permeability law is investigated, whereby most pronounced segregation occurs for the widely used Carman-Kozeny equation. Only minor influence of the resulting Si segregation on the primary arm spacing and the temperature gradient is observed. The parameter study supports the definition of the ARTEX experiment scheduled for TEXUS41.
KeywordsMushy Zone Darcy Number Rotate Magnetic Field Alternate Magnetic Field Mixture Concentration
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