The effect of non-equilibrium δ/γ transition on the formation of metastable “dendrite core” in undercooled Fe-Cu alloy

► Formation of “dendrite core” was dominated by incomplete δ/γ transition. ► Small granules and dendrite trucks in “dendrite cores” have been detected. ► Larger transition fractions corresponded to small granules. ► Smaller transition fractions corresponded to dendrite trucks.