The sub-rapid solidification behaviors of Inconel 718 superalloy with a novel droplet solidification technique were investigated by analyzing the heat transfer, macrostructure, microstructure, segregation, and precipitates. It is observed that the Nb-rich precipitates such as Laves phase and (Nb, Ti)C are formed in the interdendritic regions. The results suggest that droplet solidification method is an effective technique to improve the quality of Inconel 718 in terms of enhancing heat transfer, refining grains, reducing secondary dendrite arm spacing (SDAS) and Nb-rich precipitates. In addition, it is interestingly found that the heat flux and columnar grain zone increase, while the SDAS and volume fraction of Nb-rich precipitates decrease as the superheat increasing of 40 K, due to a larger contact area with the mold. Moreover, the quantitative relationship between the SDAS and volume fraction of Nb-rich precipitates is obtained.

通过分析传热，宏观结构，微观结构，偏析和沉淀，研究了采用新型液滴凝固技术的Inconel 718高温合金的亚快速凝固行为。观察到在枝晶间区域中形成了富Nb的沉淀物，例如Laves相和（Nb，Ti）C。结果表明，液滴凝固法在增强传热，细化晶粒，减小二次枝晶臂间距（SDAS）和富Nb沉淀物方面是提高Inconel 718质量的有效技术。此外，有趣的是，随着与模具的接触面积增大，随着40 K的过热，热通量和柱状晶粒区增加，而SDAS和富Nb沉淀的体积分数降低。此外，