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→斗细小粒状晶→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,凝固组织为品界平直的粗大等轴晶。
Adopting molten glass purification combined with cycle superheating methods, Cu98Co2 alloy was highly-undercooled systematically. Two different cooling methods (rapid quenching and natural cooling in air) were applid to study the effects of undercooling and cooling rate on the solidification microstructure, Results indicate that with the increasing undercooling the microstructure evolution process of this alloy is as following: dendrite→coarse equiaxed crystals, The dendrite growth model undercoolings, high stacking fault energy and high nucleation coarse dendrite structure→refined granular grains→refined directional was used to explain the above structure evolution process. Under large rate result in rapid recrystallization and crystal-grain growth, and the solidification microstructures are typically coarse grained equiaxed crystal with flat grain boundary.