Relation between the segregation of silicon and the pore formation during the unidirectional solidification of Al-16%Si alloy

Abstract

A correlation between the distribution of silicon and hydrogen is recognized in the unidirectional solidified Al-16% Si alloy. The crystallized primary silicon crystals do not rise in the melt, and remarkably segregate at the lower part of a ingot in spite of having lower density than molten aluminum. The mechanism of segregation of silicon in Al-16%Si alloy is explained with the equilibrium phase diagram in the same manner as the formation of cylindrical pores in pure aluminum.