Abstract:Directionally solidified Rene88DT superalloy ingots were successfully produced by electroslag remelting continuous directional solidification (ESR-CDS) technology. Compared with conventional ESR ingot, the as-cast structures of ESR-CDS Rene88DT alloy ingot were analyzed using by optical microscopy (OM)、field emission scanning electron microscopy (FESEM) with energy spectrum and transmission electron microscopy(TEM). The results showed that the ESR-CDS Rene88DT alloy ingot eliminated the region of the severe central segregation which existed commonly in the conventional ESR ingot because of the formation of intersection of interfaces between columnar crystal and equiaxed crystal or columnar crystal each other. In addition, the ESR-CDS Rene88DT alloy ingot showed smaller secondary dendritic spacing, smaller non-equilibrium precipitates phase. Due to the decreasing micro-segregation level, uniform distribution of alloy elements can be achieved when subjected to the heat treatment at 1200 oC for 24h. Statistical results of inclusions revealed that the maximum size of inclusion in the ESR-CDS Rene88DT alloy was not more than 5.89μm and the inclusion volume reduced by 60% compared with conventional ESR and P/M respectively. The hot working plasticity of directionally solidified Rene88DT superalloy can be improved, which makes a basis for implementation of cast-and-wrought (C&W) route.