Effect of Microstructural Parameters on Channel-Type Segregation Formation in DC Casting of Al–Mg Billet

The effect of microstructural parameters on channel-type segregations formed during direct chill casting of Al–Mg billets is investigated through numerical simulation by solving the momentum, mass, heat, and species balance equations coupled with phase diagram. The numerical results indicate that the strip-patterned channel-type segregations are formed under conditions when the critical solid fraction is high. The dendrite arm spacing is found to slightly affect the macrosegregation formation. Also, the diameter of floating particles in the slurry zone has a significant effect on the macrosegregation, and the larger the particle diameter is, the greater the extent of macrosegregation. These phenomena are explained in terms of flow conditions. The solutal buoyancy flow in the slurry zone is enhanced with increase of the critical solid volume fraction and floating particle diameter that result in the remarkable formation of channel-type segregations.