Dendritic solidification and fragmentation in undercooled Ni–Zr alloys
نویسنده
چکیده
Kinetics of dendritic solidification and fragmentation of dendritic crystals in undercooled Ni–Zr samples are studied. Using the capacitance roximity sensor technique and a high-speed-camera system, the dendrite growth velocity has been measured as a function of initial undercooling n solidifying droplets processed by the electromagnetic levitation technique. Analyses of solidified droplets give evidence to a transition from oarse grained dendrites to grain refined dendrites (CG-GR) at small undercooling, a transition from grain refined dendrites to coarse grained endrites (GR-CG) at moderate undercooling, and to a second transition from coarse grained dendrites to grain refined dendrites (CG-GR) at a igher undercooling. Predictions of a sharp-interface model are compared with the results of experiments on Ni–Zr samples. 2006 Elsevier B.V. All rights reserved.
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