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采用熔融玻璃净化法使大体积Co85Cu15亚包晶合金的最大过冷度达到351K（0.21TL），实验测得其超过冷临界过冷度为379K.随着过冷度的增大，显微组织由树枝晶转变为等轴晶，并显著细化；溶质截留效应增强，显微偏析程度减小,Co的同素异构转变受到抑制，凝固组织中Co主要是亚稳的过饱和α-Co固溶体,ε-Co含量极少.对初生相形核率进行了理论计算，发现在过冷度为351K时合金熔体仍然发生异质形核.依据LKT／BCT枝晶生长理论对初生相生长速度和枝晶顶端半径进行了理论计算
The maximum undercooling of large Co85Cu15 sub-peritectic alloy reached 351K (0.21TL) by melt glass purification method, and the experimental result shows that the supercooling degree exceeded the cold critical cooling temperature 379 K. With the increase of undercooling, the microstructure The dendrites transform into equiaxed grains and are significantly refined; the solute retention effect is enhanced, the degree of micro-segregation is reduced, the allotropic transformation of Co is inhibited, and the Co in the solidified structure is mainly metastable supersaturated α-Co Solid solution and very low content of ε-Co.The nucleation rate of the primary phase was theoretically calculated and found that the heterogeneous nucleation of the alloy melt still occurs at 351 K under the subcooling degree.According to LKT / BCT dendritic growth theory, the growth rate of the primary phase And the radius of dendrite tip were calculated theoretically