1995 Volume 35 Issue 2 Pages 178-182
The dendrite growth rates for Ag-5mass%Cu and Cu-10mass%Ni alloys are measured as a function of the degree of bath undercooling. The growth rates for pure silver and copper in the literature are compared with the model and the characteristic value of interface kinetics is determined by fitting the prediction curves the the data. The determined values of the upper limit or interface advance, V0, are 500 ms-1 for silver and 600 ms-1 for copper, which correspond to the values of the linear kinetic coefficient of 0.5 ms-1K-1 for silver and 0.6 ms-1K-1 for copper, respectively. With the determined values of V0 the data of dendrite growth rates for alloys are analyzed using the LKT model. The data are in good agreement with the estimation by the model only when nonequilibrium effects are assumed. The estimated values of growth rate coefficient, β0 (=a0/DL) are about 1.0 m-1 s for both alloys. The result shows that the nonequilibrium effect proposed by Aziz and by Boettinger and Coriell are quite applicable.