Effect of REE on the Solidification of Hypereutectic Silumin

The theories and mechanisms that explain the processes of modification of primary silicon in hypereutectic silumins are considered. The solidification of a hypereutectic silumin containing a rare earth element (REE), namely, yttrium, ytterbium, samarium, erbium, lanthanum, or neodymium, is studied. The phase transformation temperatures and the parameters that take into account the precipitation of a solid phase in the solidification temperature range are determined. Differences in the solidification parameters and the character of solid-phase precipitation in alloys modified by yttrium, ytterbium, samarium, erbium, cerium, or neodymium are revealed. Further investigations should be performed to clarify the mechanism of the REM modification of primary silicon in hypereutectic silumins.