Heterogeneous Nucleation Behavior in Al Deoxidized Liquid Iron

Abstract

As an important deoxidization agent, Al and its deoxidization products are rarely investigated in terms of nucleation catalyzer for liquid iron itself. Here, we tracked the atomic structure evolution of Al deoxidized liquid iron using in situ high energy X-ray diffraction method to figure out the effect of Al and its deoxidization product for the nucleation in liquid iron. The identified icosahedral short-range ordering (ISRO) and its enhancement with decreasing temperature in both the liquids investigated suggest that the type and number of ISRO is not the sole reason responsible for the variation of undercooling. A decreased nearest neighbor atomic distance (r₁) of liquid was detected with the enhanced nucleation after adding 1 mass%Al for de-oxidization. It indicates that the difference between SRO structure of Fe–1 mass%Al liquid and the corresponding crystal structure becomes small, resulting in a lower undercooling.