The effect of elemental vaporization and redistribution during sub-solvus recrystallization of a single crystal superalloy

The elemental vaporization and redistribution effect during sub-solvus recrystallization (1100 °C) of a second-generation single crystal superalloy DD6 containing 2 wt% Re has been investigated in this work. For fine polished specimens free from selective chemical erosion effect, accurate elemental energy dispersive spectroscopy (EDS) analysis was taken from the surface to the inner original matrix and across the boundary of the recrystallization reaction front. The results revealed that the vaporization induced elemental depletion of Ni and Al had occurred in the top surface layer. This would lead to the destabilization of the γ phase in the recrystallized aggregates, facilitating the final precipitation of refractory-rich P phase.