Microsegregation behavior of Inconel 718 superalloy prepared by electron beam smelting layered solidification technology

Abstract

Based on the principle of additive manufacturing in a layer-by-layer manner, a new electron beam smelting layered solidification technology (EBS-LST) was curried out to fabricated Inconel 718 superalloy. The microsegregation coefficient and the redistribution were calculated. A well-recognized model associated with secondary dendrite arm spacing was used to investigate the cooling rate during the solidification. The distribution of the surface temperature of the molten pool during EBS-LST was calculated based on the Gaussian distribution. The results show that there is a dendritic-cellular interface with a width of 400 μm between the layers, and the secondary dendrite arm spacing approximates 23 μm. The value of microsegregation coefficient of Nb, Mo and Ti is approximately 1.97, 1.52 and 1.13, respectively. Its solute distribution is more uniform than conventional processes, which attributed to the high cooling rate of the solidification process.