Kinetics of dendrite growth and dendritic fragmentation in the undercooled Co81.2Cu18.8 alloy's melt

The growth velocity during solidification of an undercooled melt of a Co-Cu alloy processed by electromagnetic levitation was measured using a high speed video camera. Applying a model of local non-equilibrium solidification, theoretical predictions of dendrite growth velocity and dendritic growth radii are compared with high-accuracy measurements of the growth kinetics. As the undercooling ΔT reaches a critical value consistent with the dendrite growth velocity being equal to the atomic diffusion speed VD in bulk liquid, ΔT = ΔT(VD), the velocity-undercooling relationship exhibits a break-point