Effects of compound molten salt on undercooling of GH4169 superalloy

The method of molten salt denucleating was applied to study the rapid solidification of GH4169 superalloy. The best compound molten salt and process parameters were gained through orthogonal experiment, then the maximum undercooling, 250K, of GH4169 superalloy was achieved, at the same time, the mechanisms of molten salt and process parameters were also investigated; the solidification morphologies of the undercooled IN718 superalloy were found to be dependent on the degree of undercooling. Through observed the microstructures of GH4169 superalloy with variable undercooling, the solidification microstructure of IN718 underwent two grain refinement, which was transferred from dendrite structure to granular grain. When the undercooling achieved 250K, the average grain size was only 5.5 μm.