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采用熔融玻璃净化配合循环过热的净化技术,对Cu98Co2合金进行了系统的深过冷实验。分别采用空冷与快淬两种冷却方法,在一定过冷度和冷却速率相结合下制备出单相固溶体探讨了过冷度及冷却速率对凝固组织的影响。实验结果表明,随过冷度提高凝固组织呈现粗大树枝晶→细小粒状晶→定向细枝晶→粗大粒状晶的演化趋势,基于枝晶生长模型,解释了上述凝固组织演化规律。在大过冷度下,由于该合金具有高层错能和高形核率,再结晶和晶粒长大迅速发生,凝固组织为晶界平直的粗大等轴晶。
The purification technology of molten glass combined with overheating cycle was used to study the deep undercooling of Cu98Co2 alloy. Two kinds of cooling methods, air-cooling and quenching, were respectively adopted to prepare the single-phase solid solution under a certain degree of supercooling and cooling rate. The effects of supercooling degree and cooling rate on the solidification structure were discussed. The experimental results show that the evolution of the solidified structure shows the evolution of coarse dendrites → fine granular crystals → directed fine dendrites → coarse granular crystals with the increase of undercooling. Based on the dendrite growth model, the evolution of the above solidified structure is explained. Under high degree of overcooling, recrystallization and grain growth occur rapidly due to the high-level fault energy and high nucleation rate of the alloy. The solidified structure is a coarse equiaxed grain with a straight grain boundary.