Applying cycle superheating and molten glass purification technologies, Cu55Ni45 and Cu55Ni43Co2 alloys were deeply undercooled to maximum undercoolings of 284 K and 250 K respectively. The microstructure characteristics and its evolution varying with bulk undercooling during the rapidly solidified process were analyzed. It was found that, after minor addition of element Co, refinement mechanisms of dendritic grain of the undercooled Cu-Ni-Co alloys was the same as those of the CuNi alloys. Dendritic grain refinement occurring at low undercooling range was induced by dendrite breakup due to remelting, while the dominant factor of the grain refinement at high undercooling range was the recrystallization process. The driving force (i.e. stress induced strain energy) for recrystallization could be divided into two parts, one was the thermal stress generated by the releasing of solidification latent heat during the recalescence process, and the other was the accumulated stress and plastic strain caused by the interaction of liquid flow and primary dendrites caused by rapid solidification.

应用循环过热和熔融玻璃净化技术，Cu55Ni45 和 Cu55Ni43Co2 合金分别深度过冷至 284 K 和 250 K 的最大过冷度。分析了快速凝固过程中显微组织特征及其随整体过冷度的变化。研究发现，少量添加 Co 元素后，过冷 Cu-Ni-Co 合金的枝晶细化机制与 Cu 相同。镍合金。在低过冷度范围内发生的枝晶细化是由重熔引起的枝晶破碎引起的，而在高过冷度范围内发生晶粒细化的主导因素是再结晶过程。再结晶的驱动力（即应力诱导应变能）可分为两部分，一是再辉过程中凝固潜热释放所产生的热应力，二是再结晶引起的累积应力和塑性应变。快速凝固引起的液体流动和初级枝晶的相互作用。