Abstract Fatigue behaviour in High Cycle Fatigue (HCF) regime has been studied in a 17–4 PH steel produced by an Additive Manufacturing (AM) technique, Selective Laser Melting (SLM). The research was prompted by increasing demands of AM techniques for safety-critical engineering applications. One of the main challenges in as-built AM parts is surface roughness, which gives rise to early crack initiation due to stress concentration leading to fatigue failure. This classical problem has been treated empirically in the past, using mainly stress-based approaches. In this work, we studied the cyclic behaviour of materials at the notch root of typical notch sizes in three material types using the finite element analysis with appropriate material models. Two distinct deformation modes are found: Shakedown or ratchetting, dependent on the applied load level. Selected critical surface locations in a specimen produced by SLM were also examined and the results are found to be consistent with those from the idealised notches. The results shed light on the fatigue damage mechanisms in HCF regime, which may be useful in AM material design and life management.

中文翻译：

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从根本上了解表面条件对安全关键型 AM 应用的抗疲劳性的影响

摘要 研究了采用增材制造 (AM) 技术、选择性激光熔化 (SLM) 生产的 17-4 PH 钢在高周疲劳 (HCF) 状态下的疲劳行为。这项研究是由于对安全关键工程应用的增材制造技术日益增长的需求。AM 部件的主要挑战之一是表面粗糙度，由于应力集中导致疲劳失效，这会导致早期裂纹萌生。过去，这个经典问题主要使用基于压力的方法进行经验处理。在这项工作中，我们使用有限元分析和适当的材料模型研究了三种材料类型中典型缺口尺寸的缺口根部材料的循环行为。发现了两种不同的变形模式：摇晃或棘轮，取决于施加的负载水平。还检查了 SLM 生产的试样中选定的关键表面位置，发现结果与理想化槽口的结果一致。结果揭示了 HCF 状态下的疲劳损伤机制，这可能有助于 AM 材料设计和寿命管理。