The influence of Si concentration on undercooling of liquid Fe

•We study undercooling of Fe–Si melts with Si concentration up to 30 at.%.•The crystallization ability of the α-Fe(Si) rises sharply near 10 at.% Si.•We suggest the numeric description of the undercooling concentration dependence.

Concentration dependences of undercooling ability, (ΔТ), of Fe–Si melts with Si concentration up to 30 at.% have been studied in this paper. It has been shown that the crystallization ability of the α-Fe(Si) solid solution rises sharply within the range from 5 to 10 at.% Si. The obtained ΔТ(х) dependence is accounted for by the change of the geometrical and chemical short-range order of the atomic arrangement. The numeric description of ΔТ(х) in the composition range up to 30 at.% Si has been carried out by the probabilistic approach used to determine various short-range ordering configurations and experimental undercooling ability values with the 2.5 and 2.7 at.% Si concentrations.