Abstract To study the effect of the building directions on surface macro- / micro- structure and tribological properties of Inconel 625 samples manufactured by selective laser melting (SLM) technology, parts were fabricated in three different building directions (0°, 45°, 90°). The microstructure of SLM samples was characterized using optical microscope (OM) and scanning electron microscopy (SEM). Only the γ-Ni phase was detected in the X-ray diffraction (XRD) patterns of the SLM samples. The lattice constant of the γ-Ni phase in the SLM 45°sample was the lowest among these SLM samples. The value of the surface roughness of the SLM 45° specimen was the highest than other parts, while, the value of the surface roughness of the SLM 0° sample was the lowest. The surface microstructure of the SLM samples was primarily composed of columnar dendrites and equiaxed grains. Among these samples, the finest equiaxed grains (about 0.38−0.63 μm) was evenly distributed in the SLM 0° sample, while, the roughest equiaxed grains (approximately 0.73–1.26 μm) was formed in the SLM 45° sample. Furthermore, the SLM 0° specimen showed the highest microhardness value (332 HV0.2) and the best tribological performances, such as the lowest average coefficient of friction (COF = 0.31) and the wear rate (57.2 × 10−6 mm3 / (N m)).

中文翻译：

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构建方向对选择性激光熔化 Inconel 625 表面粗糙度、微观结构和摩擦学性能的影响

摘要 为了研究构建方向对选择性激光熔化 (SLM) 技术制造的 Inconel 625 样品的表面宏观/微观结构和摩擦学性能的影响，在三个不同的构建方向（0°、45°、90 °）。使用光学显微镜 (OM) 和扫描电子显微镜 (SEM) 表征 SLM 样品的微观结构。在 SLM 样品的 X 射线衍射 (XRD) 图中仅检测到 γ-Ni 相。SLM 45°样品中γ-Ni相的晶格常数在这些SLM样品中最低。SLM 45°试样的表面粗糙度值最高，而SLM 0°试样的表面粗糙度值最低。SLM 样品的表面微观结构主要由柱状枝晶和等轴晶粒组成。在这些样品中，最细的等轴晶粒（约0.38-0.63 μm）均匀分布在SLM 0°样品中，而最粗糙的等轴晶粒（约0.73-1.26 μm）形成于SLM 45°样品中。此外，SLM 0°试样显示出最高的显微硬度值（332 HV0.2）和最好的摩擦学性能，例如最低的平均摩擦系数（COF = 0.31）和磨损率（57.2 × 10−6 mm3 / ( N·m))。