Liquid State Undercoolability and Crystal Growth Kinetics of Ternary Ni-Cu-Sn Alloys**Supported by the National Natural Science Foundation of China under Grant Nos 51327901 and 51301138, the Specialized Research Fund for the Doctoral Program of Higher Education under Grant No 20126102120064, the Aviation Science Foundation of China under Grant No 2014ZF53069, and the Fundamental Research Funds for the Central Universities under

Abstract

The liquid state undercoolability and crystal growth kinetics of ternary Ni-5%Cu-5%Sn and Ni-10%Cu-10%Sn alloys are investigated by the glass fluxing method. In these two alloys, experimental maximum undercoolings of 304K (0.18TL) and 286 K (0.17TL) are achieved and the dendritic growth velocities attain 39.8 and 25.1 m/s, respectively. The transition of morphology from coarse dendrite into equiaxed structure occurs and the grain size of the α (Ni) phase decreases remarkably when the undercooling increases. Both the lattice constant and microhardness increase obviously with the enhancement of undercooling. The enrichment of Cu and Sn solute contents reduces the dendritic growth velocity, while enhances the lattice constant and microhardness of α (Ni) phase.