摘要
采用熔融玻璃净化结合循环过热的方法,使Fe82.5Ni17.5合金获得了330K的最大初始过冷度。结合理论计算和组织观察,对Fe82.5Ni17.5合金在深过冷条件下的凝固行为和组织形成规律进行了研究。结果表明,过冷度ΔT<63K时,合金的凝固组织为粗大的树枝晶;当63K<ΔT<158K时,凝固再辉所产生的重熔效应非常强烈,受此影响,初生的树枝晶被熔断,形成了细化的粒状晶组织;当过冷度进一步增大至158K<ΔT<203K时,再辉所产生的重熔效应大大降低,凝固组织进一步演变为发达的树枝晶组织;而当ΔT>203K时,凝固组织的晶粒细化源于快速凝固体积骤变所产生收缩应力导致的初生枝晶碎断。
Fe82.5Ni17.5 alloys were undercooled by means of molten glass fluxing and cycling superheating methods. The maximum undercooling of 330 K was achieved. In combination of the theoretical calculations and experimental observations, the solidification behavior and structure formation mechanisms were systematically investigated. If the bulk undercooling ΔT〈63 K, the coarsening dendritic structures result. When AT is in the range of 63 K〈ΔT〈158 K, influenced by the serious remelting, which is produced by recalescence, the primary dendrite is remelted into refined spherical crystals. As AT increases to the range of 158 K〈ΔT〈203 K, due to the remelting effect decrease to a low level, the as-solidified structure evolve into dendritic structure. While ΔT〉203 K, the grain refinement is caused by the stress originating from the rapid solidification contraction.
出处
《航空学报》
EI
CAS
CSCD
北大核心
2007年第B08期178-182,共5页
Acta Aeronautica et Astronautica Sinica
基金
国家自然科学基金(50395103
50501020)
