The dendrite growth kinetics of nickel-based alloys

The solidification velocity of several compositions of Ni–Ti and Ni–Sn alloys were measured as a function of undercooling by the direct imaging of levitated drops. During this investigation a plateau in the solidification velocity was observed at intermediate undercoolings as a direct result of the addition of tin and titanium to nickel. Past work has shown an additional solidification velocity plateau at high undercoolings can be attributed to residual oxygen solute. From these results, a logistic growth model for alloy solidification was developed that can describe the solidification velocity as a function of undercooling and reproduce the plateau behavior. Finally, it is shown that a logistic growth model is more accurate for describing the solidification of alloys than thermodynamic models based on the Ivanstov solution.