SECONDARY ARM SPACING OF UNDERCOOLED Ni_(50)Cu_(50) ALLOY
过冷Ni50Cu50合金的二次枝晶间距

The secondary arm spacing of undercooled Ni50Cu50 alloy did not decrease withincreasing undercooling in a simple power law, but there was a abnormal protrusion in theirrelationship in the undercooling range of 40 -- 120 K. This phenomenon was first attributedto the increase of primary dendrite tip radius occurring in the transition from solute diffusioncontrolled dendrite growth at low undercoolings to thermally controlled dendrite growth at highundercoolings. The other cause was the substantial sidebranch coarsing induced by the remeltingwhich was extremely serious in the solidification of undercooled melts.