TEM and EBSD investigation of a Re-doped β-NiAl coating on a Ni-based single crystal superalloy.

• The EBSD and TEM were used to study the microstructures of Re-doped β-NiAl coating. • Outer layer of Re-doped β-NiAl coating was composed of coarser β-NiAl grains and nanometer sized γ-Re precipitates. • Inner layer of Re-doped β-NiAl coating was consisted of tiny β-NiAl grains and submicron sized α-W phases. • γ-Re and α-W phases were distributed in both β-NiAl grain boundaries and different zones within the grains. To figure out the microstructure and precipitation phases of a Re doped β-NiAl coating, the electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM) were both used. Re-doped β-NiAl coating was composed of outer coarser β-NiAl grains with nanometer sized γ-Re precipitates, inner tiny β-NiAl grains with submicron sized α-W phases and bottom interdiffusion zone (IDZ, consisted of strip TCP and β-NiAl phases). Moreover, these γ-Re and α-W nanoparticle phases were not only aggregated at β-NiAl grain boundary but also appeared within the grains. [ABSTRACT FROM AUTHOR]