Dendrite growth in undercooled Fe–Co melt

Fe–Co melt was undercooled using fluxing method in this work. With increasing the initial undercooling (ΔT), two kinds of dendrites were obtained in the microstructure of undercooled Fe70Co30 alloy at both low and high undercooling ranges. For ΔT < 22 K, the as-solidified morphology is similar to the conventional as-cast dendrite, whereas, for 97 K < ΔT < 173 K, a largely developed fine dendritic morphology is observed. BCT model is used to discuss the two different dendritic morphologies, in combination with a stability analysis of dendrite growth based on the morphological instability.