应用多次重复冲击方法对小模数粉末热锻齿轮和18CrMnTi齿轮进行单齿冲击试验,得出冲击能量与破断寿命次数曲线。试验结果表明在中、低挡冲击能量下粉末热锻齿轮的寿命高于18CrMnTi齿轮。应用透射复型电子显微镜及扫描电子显微镜对试验断口进行观察,研究了它们的微观断裂机制及其与宏观规律之间的关系。 The multiple repeated impact method was used to test the single-tooth impact test of the small module powder hot forging gear and 18CrMnTi gear, and the curve of impact energy and the number of broken lifetimes was obtained. The experimental results show that the life of powder hot forging gear is higher than that of 18CrMnTi gear at medium and low impact energy. Transmission electron microscopy and scanning electron microscopy were used to observe the experimental fracture and their microscopic fracture mechanism and its relationship with macroscopic regularity were studied.