Abstract
We imposed an alternating current on a commercially used aluminum alloy to control its solidified structure. It was applied in the initial stage of the solidification in a static system and during pouring from the tundish to the mold in a flowing system. In the static system, the solidified structure around the electrodes changed from a dendritic structure to an equi-axed one by imposing the current. However, equi-axed structure was not observed at the bottom of the vessel because the primary solid particles in the liquid phase remelted by the sedimentation to a relatively high temperature region. In the flowing system, the solidified structure was also modified from a dendritic structure to an equi-axed structure by imposing the alternating current except for the finally solidified region. The reason why the dendritic structure was obtained at the finally solidified region is that the current did not flow in the metal because of the discontinuous melt dripping in the pipe between the tundish and the mold in the last stage of the pouring. Therefore, it has been confirmed that imposition of the alternating current on the aluminum alloy during its solidification is a useful tool for modification of the structure from dendritic to equi-axed structures.
