In this study, fatigue crack growth (FCG) behavior of cemented carbide under the repeated thermal shock (RTS) was experimentally evaluated by using the thermal-shock experiment method developed by the authors. Tests were carried out using cemented carbide having two different WC crystal grain sizes. In addition, FCG behavior under rotating bending fatigue (RBF) test was investigated using the same cemented carbides. Then the FCG results obtained by the RTS test and the results of the RBF test obtained at stress ratio, R = -1, were compared with each other. Here, the stress ratio R is defined as, R = σmin/σmax; σmin and σmax are the minimum and the maximum stresses, respectively. From this comparison, it was found that the relation between the rate of fatigue crack growth (FCG) and the maximum stress intensity factor in the RTS tests was equivalent to the one obtained under the RBF tests at stress ratio of -1. From a practical point of view, this result is important as it indicates that it is not necessary to purposely perform RTS experiments. In this research, the effect of WC grain size on the short surface FCG behavior of the cemented carbide was also studied and discussed.
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机译：在这项研究中，使用作者开发的热冲击实验方法，对硬质合金在反复热冲击（RTS）下的疲劳裂纹扩展（FCG）行为进行了实验评估。使用具有两种不同WC晶粒尺寸的硬质合金进行测试。此外，使用相同的硬质合金研究了FCG在旋转弯曲疲劳（RBF）试验下的行为。然后，将通过RTS测试获得的FCG结果与在应力比R = -1下获得的RBF测试结果进行比较。在此，应力比 R 定义为 R = σ min /σ max ; σ min 和σ max 分别是最小应力和最大应力。从该比较中发现，在RTS测试中疲劳裂纹扩展速率（FCG）与最大应力强度因子之间的关系与在应力比为-1的RBF测试中获得的关系相同。从实际的角度来看，此结果很重要，因为它表明没有必要有目的地执行RTS实验。在这项研究中，还研究和讨论了WC晶粒尺寸对硬质合金短表面FCG行为的影响。
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