冲击和非冲击疲劳载荷下裂纹扩展的研究

对几种典型材料分别进行了四点弯曲冲击和非冲击疲劳裂纹扩展试验。结果表明，相同ΔK条件下，冲击和非冲击疲劳裂纹扩展速率之间存在三种类型的关系，这三种类型的关系与材料在两种载荷制度作用下的微观断裂机制紧密相联，统一了过去在冲击和非冲击疲劳裂纹扩展对比试验中的矛盾结果。

STUDY ON CRACK PROPAGATION IN IMPACT FATIGUE AND NON-IMPACT FATIGUE

Crack propagation in 4-point bending impact fatigue and non-impact fatigue tests were studied using a few typical alloys. It has been found that there are three different types of relations between crack propagation in impact fatigue and that in non-impact fatigue. These relations are strongly associated with the micro-fracture mechanisms under impact and non-impact fatigue loads. The contradictory test results ottained by different authors in the past on the comparative study of crack propagation in impact fatigue and non-impact fatigue can thus be unified.