This study explores the influence of geometry and part size on defect distribution, melt pool size, and mechanical characteristics in laser beam powder bed fused (LB-PBF) AlSi10Mg. Five distinct geometries—hourglass, small rod, small block, large block, and large rod—were fabricated under identical process parameters. Fully reversed ultrasonic fatigue testing, operating at a frequency of 20 kHz, was conducted to assess the very high cycle fatigue properties. The findings indicated that part geometry had a major impact on the fatigue properties of the material in the very high cycle fatigue regime. Specimens machined from large rods and large blocks had the lowest porosity and highest fatigue resistance. Microstructural analysis indicated that hourglass, small rod, and small block specimens had shallower melt pools and overlap depths compared to other geometries. This observation suggests a higher cooling rate in specimens with smaller cross-sectional areas, leading to the increased presence of entrapped gas pores and a lack of fusion defects. Understanding the relationship between part geometry and fatigue properties in LB-PBF components offers insights for optimizing design and manufacturing processes in additive manufacturing applications.

中文翻译：

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激光束粉末床熔融 AlSi10Mg 的极高循环疲劳特性：零件几何形状的系统评估


本研究探讨了激光束粉末床熔融 (LB-PBF) AlSi10Mg 中几何形状和零件尺寸对缺陷分布、熔池尺寸和机械特性的影响。五种不同的几何形状——沙漏形、小棒形、小块形、大块形和大棒形——是在相同的工艺参数下制造的。在 20 kHz 频率下进行全反向超声波疲劳测试，以评估极高的循环疲劳性能。研究结果表明，零件几何形状对材料在极高循环疲劳状态下的疲劳性能有重大影响。由大棒和大块加工而成的样品具有最低的孔隙率和最高的抗疲劳性。微观结构分析表明，与其他几何形状相比，沙漏、小棒和小块样品的熔池和重叠深度更浅。这一观察结果表明，横截面积较小的样品的冷却速率较高，导致截留气孔的存在增加并且缺乏熔合缺陷。了解 LB-PBF 部件中的零件几何形状和疲劳特性之间的关系可以为优化增材制造应用中的设计和制造工艺提供见解。