Microstructure of as-deposited Ni-Cr-Al alloy thin sheet by EBPVD

Ni-Cr-Al alloy thin sheet with 0.2 mm in thickness was deposited on a stainless substrate with 700°C from a target of Ni-Cr-Al alloy by EB-PVD, and then was removed from the substrate. The thin sheet was characterized by scanning electronic microscopy (SEM), X-ray diffraction(XRD), atomic force microscopy (AFM) and transmission electron microscopy(TEM). It is found that the alloy consists of a two layer structure with different pattern along cross-section direction. Columnar crystals are formed on the substrate side, exhibiting a strong {111} texture, while the equiaxed crystals are dominant on the evaporation side with no textures. Fine and uniform crystals, growing island-likely, are observed on the surface of the as-deposited alloy sheet, and each island consists of a lot of columnar crystals with about 100 nm size. A high density of twins is visible within the grains.