高合金化的变形高温合金铸态组织存在微观偏析较大、组织均匀性差等问题，严重影响了其后续热加工性能。为了优化变形高温合金的铸态组织，采用电子束熔炼(EBS)法熔炼GH4068合金，采用不同EBS功率熔炼10 min制备低偏析的GH4068合金铸锭。结果表明：经过EBS熔炼后的铸锭底部为细晶区，仅存在胞状偏析和胞状树枝晶，中部较大区域为竖直生长的柱状晶区，二次枝晶生长方向与柱状晶生长方向平行，顶部存在少量等轴晶，枝晶生长方向较为杂乱。成分分析表明，合金中Cr元素挥发最为明显，当EBS功率为17 kW时，其含量降低1.97%。EBS较传统真空感应熔炼(VIM) +电渣重熔熔炼(ESR)双联工艺所制备的铸锭组织更为均匀，当EBS功率为12 kW时，二次枝晶间距λ₂为44.6 μm，与双联工艺相比，λ₂减小了32.2%，铸锭枝晶区微观偏析程度明显降低，典型易偏析元素Ti和W的微观偏析程度分别降低了20.4%和18.6%。枝晶间γ′相尺寸较大、呈块状析出，而枝晶干的γ′相呈球状且尺寸较枝晶间更为均匀细小，在EBS功率为12 kW时所制备铸锭的γ′相尺寸最小且枝晶间不规则γ′相最少。在EBS过程中，熔体的实际温度远高于合金的熔化温度，熔体经过过热处理后团簇结构有效分解，元素分布更为均匀，在凝固过程中过冷度增加，熔体的均匀性遗传到凝固组织中使铸态组织细化，微观偏析程度降低。同时，在EBS过程中，由于电子束在熔池表面的轰击产生局部高温，能够有效降低合金中的N含量。

The as-cast structure of high-alloyed wrought superalloys exhibits disadvantages such as high microscopic segregation and poor microstructure uniformity, severely affecting their subsequent hot working and deformation properties. To optimize the as-cast structure of the wrought superalloy, GH4068 alloy was smelted via electron beam smelting (EBS), and its ingots with low segregation were prepared by setting different EBS powers for 10 min. The results show that the bottom of the ingots after EBS appeared to be fine grain regions, with the presence of only cellular segregation structure and cellular dendritic crystal; the large area in the middle became vertically growing columnar crystal regions, the direction of secondary dendrite crystal growth was parallel to that of the columnar crystal growth; a small amount of equiaxed crystal was observed at the top, and the growth direction of dendritic crystals was disordered. Analyzing the compositions of ingots revealed that Cr volatilization in this alloy was the most obvious; the Cr content decreased by 1.97% when the EBS power was 17 kW. The ingot structure prepared via EBS was more highly distributed than that obtained using the traditional vacuum induction melting + electroslag remelting duplex process. When the EBS power was 12 kW, the secondary dendrite spacing λ₂ was 44.6 μm, which was 32.2% less than that yielded using the duplex process, the degree of the microscopic segregation of the ingot dendrite region decreased considerably, and the degree of the microscopic segregation of the typical easily segregated elements Ti and W reduced by 20.4% and 18.6%, respectively. Furthermore, the massive precipitation of large interdendritic γ′ phases were observed, while the γ′ phases in the dendritic core were spherical and smaller in size than those in the interdendritic. Meanwhile, the ingot prepared with an EBS power of 12 kW achieved the smallest size for γ′ phases and least irregular γ′ phases in the interdendritic. In the EBS process, the actual melt temperature was considerably higher than the alloy melting temperature. After the overheating of the melt, the cluster structure effectively decomposed, elements were uniformly distributed, the degree of subcooling increased in the solidification process, and the uniformity of the melt was inherited to the solidification structure to refine the as-cast structure and reduce the degree of microscopic segregation. Meanwhile, during the EBS process, local high temperature generated due to the electron beam bombardment on the surface of the molten pool effectively reduced the N content in the alloy.