Abstract Selective laser melting (SLM), which is an additive manufacturing (AM) technology, has been widely used in industrial fields. The inherent defects resulting from the SLM process are inevitable. The effect of building directions on the static mechanical properties has been observed. However, certain critical functional components are under cyclic loads and extreme service conditions. The effect of inherent defects and building directions on the high cycle fatigue (HCF) performance of SLM alloys is not very clear. More testing data should be provided. Therefore, in the present work, the rotation bending fatigue (RBF) tests of SLM AlSi10Mg bar samples that included three building directions are carried out. These results indicate that most fatigue cracks initiated from the unmelted defects of the sample surfaces (or subsurface). The SLM building directions have an obvious impact on the AlSi10Mg alloy fatigue properties. The 0° samples exhibit a higher fatigue limit value than the 45° and 90° samples. Moreover, the crack propagation mechanism is revealed by fracture analysis. The negative effect of multiple-crack initiation on the RBF specimen fatigue lives under low cyclic loads is explained in detail. Finally, the evaluation method for the fracture toughness (KIC) by the fracture surfaces of the RBF samples is provided.

中文翻译：

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激光选区熔化制备AlSi10Mg合金的高周疲劳性能

摘要 选择性激光熔化（SLM）是一种增材制造（AM）技术，已广泛应用于工业领域。SLM 工艺产生的固有缺陷是不可避免的。已经观察到建筑方向对静态机械性能的影响。然而，某些关键功能部件处于循环负载和极端使用条件下。固有缺陷和构建方向对 SLM 合金高周疲劳 (HCF) 性能的影响还不是很清楚。应该提供更多的测试数据。因此，在目前的工作中，对包括三个构建方向的 SLM AlSi10Mg 棒材样品进行了旋转弯曲疲劳 (RBF) 测试。这些结果表明，大多数疲劳裂纹源于样品表面（或次表面）的未熔化缺陷。SLM构建方向对AlSi10Mg合金疲劳性能有明显影响。0° 样品表现出比 45° 和 90° 样品更高的疲劳极限值。此外，通过断裂分析揭示了裂纹扩展机制。详细解释了多裂纹萌生对低循环载荷下 RBF 试样疲劳寿命的负面影响。最后，提供了通过RBF样品的断裂面评估断裂韧性（KIC）的方法。详细解释了在低循环载荷下多重裂纹萌生对 RBF 试样疲劳寿命的负面影响。最后，提供了通过RBF样品的断裂面评估断裂韧性（KIC）的方法。详细解释了在低循环载荷下多重裂纹萌生对 RBF 试样疲劳寿命的负面影响。最后，提供了通过RBF样品的断裂面评估断裂韧性（KIC）的方法。