Grain refinement of Fe75Ni25 alloys at low undercooling

The grain refinement of Fe75Ni25 alloys at low undercooling was investigated by fluxing and cyclic superheating methods. Grain refinement was observed if the initial undercooling exceeds 56 K. Based on theoretical calculations and experimental observations, the grain refinement mechanism was achieved, and can be attributed to the breakup of dendrite–skeletons by remelting.