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采用熔融玻璃净化与循环过热相结合的深过冷技术,对比研究了深过冷凝固和过冷熔体Cu模激冷凝固Fe_(44)Co_(44)Nb_7-B_4Cu_1块体合金的组织特征.结果表明,随过冷度增大,深过冷和深过冷Cu模激冷凝固组织均由最初的发达树枝晶逐渐演变为细小的粒状晶,并且Cu模激冷可显著减小树枝晶向粒状晶转变的临界过冷度.在相同过冷度下,过冷熔体Cu模激冷凝固组织更加细小均匀,其根本原因在于Cu模激冷和熔体深过冷的双重作用不仅提高了熔体的形核率并抑制了晶粒长大,而合金化元素在晶界聚集并不是阻碍晶粒长大的主要原因.
The deep undercooling technique combining the purification of molten glass and overheating cycle was used to study the microstructure of Fe_ (44) Co_ (44) Nb_7-B_4Cu_1 bulk alloy with deep overcooling and undercooled Cu mode. The results show that with the increase of undercooling, the quenched and solidified microstructures of deep and undercooled Cu molds evolve from the initial dendrites to fine granular crystals, and the chilling of the Cu mold can significantly reduce the dendrite growth Granular crystal transition critical undercooling. Under the same undercooling, undercooled melt Cu mode chilled solidification microstructure is more uniform, the fundamental reason is that Cu mode chilling and deep melt undercooling not only enhance the dual role The nucleation rate of the melt and the inhibition of grain growth, and the alloying elements in the grain boundary aggregation is not hindered the grain growth of the main reasons.