Directional solidification velocity of undercooled Cu70Ni30 alloy melt

The directional dendrite growth velocity in the Cu70Ni30 alloy melt undercooled by 90-185 K was measured by high speed cinematography, and compared with the calculated free dendrite growth velocity. It is found that at lower undercoolings the interaction between the adjacent directionally growing dendrites is weak, and there is not a marked difference between the velocity of the directionally growing dendrite and that of free dendrite. But with undercooling increasing, the interaction is enhanced due to the decrease of the primary arm spacing, which makes the velocity difference enlarge quickly.