Thermophysical properties and rapid solidification of an undercooled liquid hexabasic Ni-based alloy

The surface tension and specific heat of liquid Ni-5%Cu-5%Fe-5%Co-5%Sn-5%Ge hexabasic alloy were measured over a broad range of temperature. The maximum undercooling obtained in the experiments is 363K (0.22T(L)). The surface tension value is determined as 1.460N m(1) at the liquidus temperature of 1652K, while its temperature coefficient is 6.361 x 10(4) N m(1)K(1). The specific heat value is determined to be 41.49 +/- 1.210J mol(1)K(1) in the temperature range from 1289 to 1850K. The dendritic growth velocity of -Ni solid solution phase within the liquid alloy was measured as a function of undercooling, which attains 25.4m s(1) at the undercooling of 358K. The rapid dendritic growth results in the significant solute trapping of all the five solutes. The lattice constant of -Ni solid solution phase is found to increase with the extent of solute trapping. A microstructural morphology transition occurs from well-branched dendrites into equiaxed grains with the rise of undercooling.