Fatigue properties of parts built by Additive Manufacturing (AM) are strictly related to process-induced defects and complex surface morphology. Several studies have proved that surface valleys act as crack initiation sites, similarly to surface micro-notches. However, different roughness parameters have been considered in literature for the depth of the surface notches, together with the adoption of a shielding factor. The aim of this study is to understand how the surface complexity of L-PBF (Laser-Powder Bed Fusion) AlSi10Mg cylindrical specimens in as-built condition can affect the fatigue behaviour. In detail, CT (Computer Tomography) scans were adopted to characterize the surface quality and 2D FE (Finite Element) analyses were used to calculate the local stress intensity factor at the most critical valleys in the surface. The results of the FE analyses were compared with a shielding factor determined for regularly spaced notches. In spite of the significant scatter, the average geometric factor value for surface notches in L-PBF surfaces is correctly predicted by the traditional shielding factor.

增材制造 (AM) 制造的零件的疲劳特性与工艺引起的缺陷和复杂的表面形态密切相关。几项研究已经证明，表面谷作为裂纹起始点，类似于表面微缺口。然而，文献中已经考虑了不同的粗糙度参数来计算表面凹口的深度，并采用了屏蔽系数。本研究的目的是了解 L-PBF（激光-粉末床融合）AlSi10Mg 圆柱形试样在竣工条件下的表面复杂性如何影响疲劳行为。具体而言，采用 CT（计算机断层扫描）扫描来表征表面质量，并使用 2D FE（有限元）分析来计算表面最关键谷处的局部应力强度因子。有限元分析的结果与为规则间隔的缺口确定的屏蔽系数进行了比较。尽管存在显着的散射，L-PBF 表面中表面凹口的平均几何因子值可以通过传统的屏蔽因子正确预测。