Three-dimensional characterization of an oxide scale on ATI 718Plus® superalloy

•FIB-SEM tomography supported by advanced TEM was an effective tool for 3D characterization of phases in oxidized 718Plus.•A discontinuous δ-Ni3Nb phase interlayer had formed directly underneath the Cr2O3 scale.•Al2O3 particles precipitated predominantly at grain boundaries.•Isolated chromia particles were present in the internal oxidation zone.•Nanosized γ phase precipitates enriched with Fe and Co were found within the Cr2O3 scale. The presented study was devoted to the characterization of a scale formed on the ATI 718Plus® superalloy. Novel complementary techniques were applied to precisely describe the structure, chemistry, morphology of the scale as well as the spatial distribution of phases formed during oxidation. The study revealed a discontinuous interlayer of the δ-Ni3Nb phase that had developed underneath the protective Cr2O3 scale. Al2O3 particles, which had precipitated predominantly at grain boundaries, and isolated chromia particles were present in the internal oxidation zone. Nanosized γ phase precipitates enriched with Fe and Co were embedded into the scale.