Fatigue crack growth is the essential process in the total life of components and is unavoidable in most structures and machines. In this study, the effects of cementite particles on the fatigue properties of medium carbon steel were investigated. A quenching and tempering treatment was developed to obtain uniformly distributed cementite particles with dozens of nanometres. To evaluate the fatigue properties, fatigue strength, fatigue crack growth rate and dynamic mechanical behaviour were examined. It was found that the fatigue strength of the tempered steel is much higher than that of air cooling ferrite/pearlite steel because the cementite particles act as barriers and hinder crack propagation during cyclic loading. More importantly, the high sensitivity of the damping peak to prior fatigue may play an important role on the fatigue history of multiphase medium carbon steel.

中文翻译：

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多相中碳钢的疲劳行为：铁素体/珠光体与回火组织的比较

疲劳裂纹扩展是组件总寿命中必不可少的过程，在大多数结构和机器中都是不可避免的。在这项研究中，研究了渗碳体颗粒对中碳钢疲劳性能的影响。开发了淬火和回火处理以获得数十纳米的均匀分布的渗碳体颗粒。为了评估疲劳性能，检查了疲劳强度，疲劳裂纹扩展率和动态力学性能。结果发现，回火钢的疲劳强度比空冷铁氧体/珠光体钢高得多，这是因为渗碳体颗粒在循环载荷过程中起着屏障和阻碍裂纹扩展的作用。更重要的是，