Self-modification in direct electrolytic Al–Si alloys (DEASA) and its structural inheritance

Electrolytic reduction of unpurified bauxite can give an aluminum–silicon alloy with high impurity content. Experiment has shown that the eutectic microstructure in either hypoeutectic or eutectic alloys has the fine fibrous appearance of an impurity-modified alloy produced by conventional methods from pure aluminum and silicon. This self-modification persists after repeated re-melting. The undercooling in solidification of re-melted alloy caused the self-modification inheritance. It is argued that self-modification is associated with the electrolytic process in reduction cell rather than trace elements in alloy.