The work is a continuation of research on the use of water mist cooling in order to increase efficiency of die-casting aluminum alloys using
multipoint water mist cooling system. The paper presents results of investigation on crystallization process and microstructure of synthetic
hypereutectic AlSi20 alloy. Casts were made in permanent mold cooled a with water mist stream. The study was conducted for unmodified
AlSi20 alloy and a modified one with phosphorus, titanium and boron on the research station allowing sequential multipoint cooling using
a dedicated program of computer control. The study demonstrated that the use of mold cooled with water mist stream and solution heat
treatment allows in wide range for the formation of the microstructure of hypereutectic silumins. It leads to the growth of microstructure
refinement and spheroidizing of phases in the casting.