过冷Ni50Cu50合金的二次枝晶间距随过冷度的增加并不以简单的幂函数规律减小，在40—120K过冷度范围内有一反常的变化理论分析指出这是枝晶生长从低过冷下的溶质扩散控制向高过冷下的热扩散控制转变过程中一次枝晶尖端半径的上升所致与常规凝固合金相比．深过冷合金的二次校晶在凝固过程中发生剧烈的粗化 The secondary dendritic spacing of the undercooled Ni50Cu50 alloy does not decrease with the law of simple power function with the increase of undercooling. Anomalous changes occur in the range of 40-120K undercooling. The theoretical analysis indicates that the dendrite growth from lower The cooling of the solute diffusion controls the increase of the primary dendrite tip radius during the transition to thermal diffusion control under high subcooling as compared to the conventional solidified alloy. Deep secondary cooling of the overcooling occurs during the solidification of coarse coarsening