电子束物理气相沉积Ni-Cr-Al合金薄板微观组织研究

Microstructure of As-Deposited Ni-Cr-Al Alloy Thin Sheet by EBPVD

采用电子束物理气相沉积技术(EB-PVD)在温度为700℃的不锈钢基片上沉积厚度为0.2mm的Ni-Cr-Al高温合金薄板,然后将合金薄板与基片剥离。采用X射线衍射(XRD)、扫描电子显微镜(SEM)、原子力显微镜(AFM)和透射电子显微镜(TEM)等测试手段研究了Ni-Cr-Al合金薄板的微观组织。结果表明,沿厚度方向合金具有两种不同晶粒形貌的两层结构,在沉积材料的靠近基板侧观察到柱状晶区,同时表现出{111}织构,而在远离基板一侧晶粒形貌则为近等轴晶且无织构现象;合金表面晶粒细小均匀且呈岛状分布,每个"岛屿"由许多晶粒尺寸约为100 nm柱状晶粒组成;晶粒内部亚结构表现为孪晶。

Ni-Cr-Al alloy thin sheet with 0.2mm in thickness was deposited on a stainless substrate with 700℃ 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 100nm size. A high density of twins is visible Within the grains.