The fatigue behavior of a C70250 alloy has been studied. The crack propagation behavior was investigated by performing fatigue crack propagation tests at load ratio R varying over the range 0.3-0.7. A considerable crack deflection and jagging was observed at low R-ratio. The study of the crack paths revealed that the closure effect is more relevant for R=0.3. In this case the crack path is characterized by considerable peak heights and deflection angles and the closure effect is mainly related to the fracture surface mismatch. The main crack propagation micro-mechanisms observed are transgranular with few areas characterized by intergranular fracture.

已经研究了 C70250 合金的疲劳行为。通过在 0.3-0.7 范围内变化的载荷比 R 下进行疲劳裂纹扩展测试来研究裂纹扩展行为。在低 R 比下观察到相当大的裂纹偏转和锯齿。裂纹路径的研究表明，闭合效应与 R=0.3 更相关。在这种情况下，裂纹路径的特点是相当大的峰高和偏转角，闭合效应主要与断裂面不匹配有关。观察到的主要裂纹扩展微观机制是穿晶的，很少有以晶间断裂为特征的区域。