奥-贝球铁疲劳损伤过程的在线跟踪分析

应用系统分析的方法，通过三点弯曲疲劳试验，跟踪监测了奥-贝球铁试样的疲劳损伤过程。实验结果表明，在循环加载过程中，奥-贝球铁中石墨球与基体组织间的界面首先发生疲劳损伤开裂，在多数情况下疲劳裂纹并不在界面开裂处萌生，进一步的疲劳损伤是由于界面的开裂不同程度影响了基体组织内的滑移等塑性变形，并在基体内萌生疲劳裂纹。试验表明奥-贝球铁中石墨球与基体组织间的界面具有一定的疲劳强度。

Fatigue Damage Detection on Line in Austempered Ductile Iron

A measurement of fatigue damage before crack initiation in austempered ductile iron under three-point-bending cyclic loading was carried out by using system analysis method. The parameter of fatigue damage is deduced. The test results show that separation at interface between graphite and matrix occurs firstly under cyclic loading, however, the separated interface do not always grow into fatigue cracks. In more cases, the separated interface can promote the formation of slip band and the initiation of fatigue cracks in the surrounding matrix.The development of the slip band into fatigue cracks is observed. The test results indicate the existence of fatigue strength of interface between graphite and matrix in austempered ductile iron.