The investigation of recrystallization developed in the largely undercooled Ni-3Â at.% Sn alloy

Using the molten glass purification combined with the cycle superheating methods, a refined grain was achieved in undercooled Ni-3 at.% Sn alloy. The characteristics of microstructures and substructures of the refined grain were investigated by the classical nucleation theory, the dimensionless superheating model and the stress accumulation model. The grain refinement occurring inevitably at high undercooling (ΔT) was ascribed to the plastic deformation of dendrites and subsequent recrystallization, which were evidenced by the transmission electron microscopy (TEM) (e.g. different types of dislocations, defects and sub-grain boundaries) and high-resolution TEM (e.g. misorientation and different plane spacings).