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本文通过力学分析和扫描电镜观察，研究了点接触条件下有表面滑动和无表面滑动摩擦时的接触疲劳裂纹萌生和扩张行为，指出了接触疲劳破坏的典型特征和一般特征．结果表明，在边界润滑条件下，接触疲劳裂纹萌生于表面，以Ⅱ型方式向纵深扩张，裂纹扩张走向与裂纹尖端处最大切应力走向一致．有表面滑动摩擦时，典型的裂纹扩张路径（或剥落坑形状）由呈Ｕ字形的四个阶段组成，无表面滑动摩擦时，扩张路径则由Ｖ字形的三阶段组成；一般的破坏以连续剥落的方式发展，它由相应条件的典型扩张各阶段随机组成．
In this paper, contact fatigue crack initiation and propagation behavior under the condition of surface sliding and no surface sliding friction under point contact is studied by mechanical analysis and scanning electron microscopy. The typical and general characteristics of contact fatigue failure are pointed out. The results show that under the condition of boundary lubrication, the contact fatigue crack initiates on the surface and expands in depth in a type Ⅱ mode. The crack propagation direction is consistent with the maximum shear stress at the crack tip. When there is surface sliding friction, the typical crack propagation path (or peel pit shape) consists of four phases in a U-shape. When there is no surface sliding friction, the expansion path consists of three V-shaped phases; The way of development, which consists of the corresponding conditions of the typical stages of expansion of random composition.