Cu-50 at% Co and Cu-68.5 at% Co metastable monotectic Cu–Co alloys have been rapidly solidified in a 6.5 m drop tube facility under nitrogen atmosphere. Microstructural evidences proved that liquid phase separation occurred in the alloys as predicted by the phase diagram of the alloy system. As well as liquid phase separated structures, substantial amount of dendrites were also observed. The resulting undercooled metal powders were sieved into ten size fraction range and the SDAS measurements taken using SEM images. Owing to the large number of liquid phase separated structures in the Cu-50 at% Co alloy, SDAS measurements were taken from six size fractions while in the Cu-68.5 at% Co alloy measurements were limited to three size range due to the fragmented nature of its dendrites as the droplet size fraction reduced. A regression relationship between cooling rate and the experimental SDAS measurements was established and an expression of the type ${\lambda }_{\text{SDAS}}=\text{Λ}{\left(\dot{\text{T}}\right)}^{-n}$ was observed in both of the alloys in which the exponential value (n) is approximately 0.2.

Cu-50 at% Co 和 Cu-68.5 at% Co 亚稳态单晶 Cu-Co 合金已在氮气氛下的 6.5 m 落管设备中快速凝固。显微组织证据证明，如合金体系相图所预测的那样，合金中发生了液相分离。除了液相分离结构外，还观察到大量的枝晶。将所得过冷金属粉末筛分为十个粒度范围，并使用 SEM 图像进行 SDAS 测量。由于 Cu-50 at% Co 合金中存在大量液相分离结构，SDAS 测量是从六个尺寸部分进行的，而在 Cu-68.5 at% Co 合金中，由于其碎片性质，测量结果仅限于三个尺寸范围其枝晶随着液滴尺寸分数的减小而减少。${\lambda }_{\text{SDAS}}=\text{Λ}{\left(\dot{\text{吨}}\right)}^{-n}$ 在指数值 (n) 大约为 0.2 的两种合金中都观察到了。