Microstructural Evolution and Applied Performance of a Highly Undercooled Bulk Ni-5% Cu Alloy

Rapid solidification with a high degree of undercooling is an important method for investigating the metastable solidification of metallic materials. In this paper, we study the microstructural evolution and applied performance characteristics of bulk Ni-5% Cu alloys with degrees of undercooling ranging from 53 to 380 K by a glass fluxing technique. The microstructure homogeneity increases, and the grain refinement increases with increasing degree of undercooling. The global microstructure transforms from a coarse dendrite microstructure into a refined equiaxed grain microstructure as the degree of undercooling increases. Additionally, EDS results illustrate that the segregation less solidification with a remarkable solute trapping effect is preferentially achieved under high undercooling conditions. The compressive yield strength, Vickers hardness and bending modulus of the bulk Ni-5% Cu alloy all increase with increasing melt undercooling. Moreover, the soft magnetic properties of the alloy are modulated when the degree of undercooling changes.